This is something of a prequel to Finishing of Gillette Razors and Razor Blades (1956) that I posted on Friday. This time I have a pair of articles from Machinery and Production Engineering, vol. 31, no. 97 (1927, p76-80, p97-100). These originally appeared one week apart in late October 1927. Together they tell us about the Gillette UK Slough factory and its manufacturing practices ca. 1927, during the New Improved era.
Unknown to Gillette or the reporter, this was just before the upheavals of the NEW era. The style is pretty dry and technical, but reveals quite a bit about Gillette operations at the time. Jump to the end for a bit about blade gap, for example.
There is always a risk of inaccuracies, so use your critical thinking skills. Nomenclature can also be different than what we use. For example the author talks about "new improved", "standard", and "pocket edition". Based on the descriptions I think the "pocket edition" was an Old Type. The "standard" meant a long-threaded New Improved, what we sometimes call a two-piece: something like the "New Standard" package. The "new improved" seems to mean a short-thread three-piece: a Tuckaway or similar.
I apologize for any typos and for the lack of illustrations: there is a list of captions at the end. You may notice a number of "???-inch" notations, in places where the text was illegible to my eyes. I hope the gist of each process is still clear.
List of Figures
Unknown to Gillette or the reporter, this was just before the upheavals of the NEW era. The style is pretty dry and technical, but reveals quite a bit about Gillette operations at the time. Jump to the end for a bit about blade gap, for example.
There is always a risk of inaccuracies, so use your critical thinking skills. Nomenclature can also be different than what we use. For example the author talks about "new improved", "standard", and "pocket edition". Based on the descriptions I think the "pocket edition" was an Old Type. The "standard" meant a long-threaded New Improved, what we sometimes call a two-piece: something like the "New Standard" package. The "new improved" seems to mean a short-thread three-piece: a Tuckaway or similar.
I apologize for any typos and for the lack of illustrations: there is a list of captions at the end. You may notice a number of "???-inch" notations, in places where the text was illegible to my eyes. I hope the gist of each process is still clear.
The Manufacture of Safety Razors I
October 20, 1927
The Practice of the Gillette Works, Ltd., Slough
The Gillette Works, Ltd., Slough, are concerned only with the production of safety razors, the blades being made in Canada from Sheffield steel. The daily output from the factory is 12,000 razors, which gives a time factor per razor of approximately 2 1/2 seconds. The brass from which the razors are made is supplied by the Delta Metal Co. and by McKechnie Bros., Ltd. It is of approximately 66/33 composition and has to conform to a rigorous specification in order that it may stand up to the high speeds employed in the turning and tapping operations. The weekly consumption of brass is five tons.
The factory is well arranged and admirably lighted by means of extensive sky lights in the roof, and the comfort of the employees, of whom some 90 per cent are girls, has been studied in that wherever possible they are provided with comfortable chairs with backs.
In all, three models of razors are made in the factory, and these are known respectively as the new improved, standard, and pocket edition. It is with the production of the two last named that the present article is concerned, and attention is here called to the heading block in order that the difference in the constructional details of the two models may be appreciated. At A the pocket edition is shown assembled, while its component parts are indicated at B, C, and D. The cap B is common to both models with the exception of the fact that in the case of the standard razor a longer threaded centre pin is fitted. Another common component is the knurled outer tube of the handle.
In the case of the pocket edition the ball top E, and the handle extension F, remain as separate components until the final assembly, when they are pressed into position in the ends of the tube after plating. The extension F is drilled and tapped to receive the threaded centre pin of the cap B. The guard D, which it will be noticed in this case remains as a separate part, is counterbored, as seen in the figure, to receive the end of the handle extension on assembly.
The standard model shown at G in the figure also comprises three parts, the cap L, the guard and handle assembly H, and the inner tube K. The handle extension is drilled to clear the threaded centre pin on the cap and is secured to the guard by spinning before assembly with the outer tube. The inner tube K is turned on the greater part of its length to conform with the inside diameter of the outer tube, while the end is tapped to receive the threaded centre pin of the cap.
Operations on the Cap
The material from which the caps are formed is received in the form of extruded brass rod of the correct crescent section. The lower limit on the length of the rods as received is 16.5 inches, the upper limit being 16.5625 inches. The stock is slit to length on a Birkett No. 00 milling machine, as shown in Fig. 1. The automatic feed on this machine has been dispensed with as being altogether too slow for the purpose of slitting. The fixture A is grooved to accommodate the stock, the end of which is seen at B. The stock is fed by hand against a stop and the fixture is traversed by hand beneath the saw by means of the hand lever shown. The work is clamped for cutting by the spring steel pads C, but as the slide is moved back at the end of the cut the curved ends of the pads ride up an inclined surface on the block D, thereby freeing the work, which can be fed forward for the next cut.
The spring steel strip E has a curved pad on its lower side. This pad slides over the work during cutting, and immediately the piece is freed by the saw it is thrown out at the side of the machine. One cut is taken to square the end of the stock, so that in all, eleven cuts are necessary to produce ten pieces. The 3 1/2-inch diameter by 0.056-inch thick saw runs at 2,400 revolutions per minute, and a production of 12,000 pieces in 8 1/2 hours is maintained. The length of the pieces from this operation is 1.5725 ± 0.001-inch.
It is interesting to record that this method of slitting to length is shortly to be superseded. A special machine for the purpose is under construction at the Gillette works. This machine will consist essentially of a rotating drum grooved longitudinally on the periphery to receive the stock, which will be held in position by curved spring clamps. The stock will pass under a gang of saws carried on an arbor, so that all the pieces will be cut from each strip simultaneously. Lateral grooves on the surface of the drum will provide clearance for the saws. This machine will give a minimum production of 10,000 pieces per hour. The pieces are next washed first in hot caustic soda solution, and finally in hot water to remove all swarf and grease. After being dried on a steam-heated hot plate, they are arranged in packs of 10, for the convenience of the operator at the next operation, and inspected.
The next operation on the caps, namely, that of punching three holes to take the locating studs and centre pin, is performed on the No. 20 Bliss press shown in Fig. 2. The press is fed by a magazine, and the punching operation is conducted at the rate of 140 pieces per minute. The magazine feed is actuated through the bracket A, Fig. 3, attached to the ram of the press, and thence through the vertical rods B to the bell-crank lever C. This lever operates the horizontal feed slide D through a connecting link.
The work is located endwise during punching by a spring-controlled latch. To free the work the latch is depressed by the pin A, Fig. 2. The mechanism is so adjusted that the latch is not depressed until the pieces of work in the feed slide are under pressure from the upper cushioning springs on the vertical rods B, Fig. 3. The result is that as soon as the latch is depressed the punched work jumps free, and the latch returns to its original position before there is any tendency for the next piece of work in the feed slide to pass over it.
The work is located sideways between an adjustable stop at B, Fig. 2, and a spring-loaded plunger, since it is necessary that the position of the holes should be held within close limits. The lateral position and centre distance of the holes is checked on the "go" and "not go" gauge, seen at C in the figure, while the distance between the end holes and the end of the work is determined by means of the "go" and "not go" gauge D. The centre distance of the end holes is 1.000 inch ± 0.0005-inch.
After punching, the three holes are countersunk on the Gillette Safety Razor special machine shown in Fig. 4. This machine is automatic in action. The three spindles carrying 60-degree countersinks are reciprocatcd by a cam, while the feed slide A is actuated by a track cam carried on a spindle to the rear of the machine. The spindles run at 2,880 revolutions per minute, and a production of 24,000 pieces per 8 1/2 hours is maintained.
A second washing operation is here introduced, and the caps are then ready for assembly with the studs.
It is convenient here to describe the method by which the studs and centre pins are produced. The studs are made from 1/16-inch brass rod, supplied in 12-ft. lengths, on a No. 00 Brown & Sharpe automatic. A circular form tool on the rear slide parts off the finished work, and at the same time forms the curved end of the next stud, while a tool in the front slide turns the rivet end. The finished stud is then fed forward against a stop, whereupon it is parted off by the rear slide tool while the forming of the next stud is in progress. The spindle speed of the machine is 5,000 revolutions per minute, and a production of 60 pieces per minute is obtained. The limits on the length of the pin are ± 0.001-inch, while on the rivet end, which has a taper of 0.004-inch on a length of 0.13-inch, there is a tolerance on the diameter of 0.001-inch.
The centre pins are turned on a No. 00 Brown & Sharpe form and cut-off machine.
After washing, the studs and centre pins pass to the cap assembly bench. The two studs are first assembled with the cap on a small bench press, the studs being a good press fit in the holes. This work is performed by girls, each of whom assemble the studs in 6,000 caps in 8 1/2 hours.
Before the assembly of the centre pins the studs are riveted on a Townsend bench riveting machine. The studs are located in holes beneath the riveting punch. A chisel-ended punch is employed which is rotated by spur gearing. The punch is reciprocated by its upper end engaging with a number of rollers which are carried in twelve holes equally spaced round the periphery of a vertically-mounted disc. The holes are larger in diameter than the rollers, which are thrown outwards by centrifugal force and deliver blows to the work as they pass over the punch. The disc is run at a speed of approximately 1,300 revolutions per minute, so that blows are delivered to the work at the rate of 15,600 per minute. On this machine 24,000 studs are riveted in 8 1/2 hours.
The centre pins, whether for the pocket edition or standard razor, are assembled in presses similar to that used for assembling the studs, and riveted.
The next operation on the cap assembly is that of threading the centre pin. This is performed on a threading machine made by the Harrison Machine Tool Co. and shown in Fig. 5.
The work is dropped into position in a shaped slot in the block A and rests on the projection B, Fig. 6. The spindle C, Fig. 5, is moved forward by hand to bring the work up to the threading die. Pressure of the work on the die pauses the die spindle, and consequently the double-coned pulley clutch D which is keyed to it, to retire. This brings the clutch D into engagement with the inside taper surface of the rear pulley E, and consequently the drive to the die is taken from the pulley E in the correct direction for threading the die on to the work. To disengage the work from the die it is merely necessary to draw back the spindle C. This withdraws the pulley D from engagement with the pulley E and causes it to engage with the pulley F rotating in the opposite direction so that the die is unscrewed from the work.
Fig. 6 shows the arrangement whereby the finished work is ejected. As the spindle is drawn back with the work clear of the die the curved end of the rod G engages with the spindle bearing support. This causes the rod G to pivot about the point H. The rod K and projection B on which the work rests are thereby withdrawn and the finished work drops out. The output for this operation is 7,500 pieces per 8 1/2 hour day.
To remove the slight burr left by the riveting operation a milling operation is introduced. This is performed on the Brown & Sharpe No. 0 plain milling machine shown in Fig. 7 and 8. Two milling cutters, concave ground to suit the profile of the work, are carried on the arbor. The jig used for this operation holds 18 pieces. The loading arrangements are shown in Fig. 7. The clamping pads are raised by the hand levers shown in the figure, and the work is located by studs and centre pins engaging in holes in the jig. The slide is pushed back under the cutters by hand and the automatic feed is then engaged for the forward traverse. As each pair of caps passes under the cutters they are clamped in position by spring pressure owing to the rollers, seen in Fig. 8, being depressed as they pass under the projecting plate A. It will be observed from Fig. 7 that the clamp securing the first 10 pieces can be raised for unloading and loading while the remaining pieces are passing under the cutters. This operation is completed on 8,500 pieces in 8 1/2 hours.
The No. 19 Bliss press shown in Fig. 9 is used to trim the edges of the cap. The work is located on the die by means of the end studs and centre pin. Before the press can be tripped by the lever A it is necessary that the lever B shall be depressed: as an additional safeguard a Broughton guard is provided. It will be noticed that the press is inclined, the finished pieces sliding off the die plate into the collecting box. The production from this operation is 7,500 pieces in 8 1/2 hours. To remove the burrs set up by the press in the last operation two filing operations are introduced. At the first of these the cap is located in three holes and pressed down by hand while two small curved files are reciprooated beneath the ends. This operation is conducted at the rate of 10,000 pieces in 8 1/2 hours.
The second filing operation is performed on the filing machine shown in Fig. 10, which is a Gillette Safety Razor special machine. The work is placed in position, as shown, locating in three holes, and is pressed down by hand on two files which reciprocate beneath the edges. Pressure on the bar A causes the vertical rack seen in the figure to rotate the spindles carrying the files through spur gears meshing with it. The files are thus constrained to move up round the sides of the work so that the upper corners are rounded off. On this machine 7,000 pieces are dealt with in 8 1/2 hours.
After inspection, the caps pass to the machine, shown in Fig. 11, where the ends are polished. This operation is common to both caps and guards. A rotating drum carries the work between two emery-faced buffs. Guards and caps are loaded on the drum alternately by two girls standing at either side of the machine. The guards are located on short pegs, and the caps in holes in the drum, and the work is secured by a spring clamp as it passes between the buffs. The drum makes one revolution in 30 seconds, during which time 32 pieces, or 16 of each sort, are completed.
The end polishing concludes the machine shop operations on the caps, which then pass to the polishing and platingshops. The component and principal dimensions are indicated in Fig. 12, the cap shown being that for the standard model.
Operations on the Guard
The guard, which is also formed from extruded stock of appropriate cross section, is slit to length on the milling machine shown in Fig. 1. A second fixture is substituted to accommodate the altered section of the stock, which is in 12-inch lengths, from which seven pieces are cut in eight strokes, otherwise the operation is identical. After being washed the parts then pass to the machine shown in Fig. 13, which was made especially for the Gillette Works by the Liberty Machine Tool Co. The operation here involved is that of rolling the trade mark on the underside of the guard. The work is fed from the magazine by a cam-operated feed slide. The motion of the feed slide causes the spindle A which carries the roller stencil to oscillate through the agency of the spring-tensioned chain seen in the figure. Thus the trade mark is rolled on the work during the forward movement of the feed slide, and during the return stroke the roller returns to its initial position. On the forward stroke the work passes under the rounded end of a pivoting hook-ended latch B. This latch drops behind the work at the end of the stroke, and as the slide recedes the work is prevented from being carried back, and drops into a chute in the machine bed. This operation is performed on 24,000 pieces in 8 1/2 hours. The holes in the guard are pierced on the Bliss press shown in Fig. 2, this operation being the same as that of piercing the caps, with the exception that the holes are a clearance fit for the studs and centre pin on the cap.
To accommodate the handle extension on assembly the centre hole in the guard is counterbored on the lower concave side. Before this operation the pierced guards are inspected, and then pass to a machine identical with that shown in Fig. 4. A small end mill is carried on the central spindle, and an extension of the spindle pilots in the hole to ensure the concentricity of the counterbore. The output from this operation is the same as that for the countersinking of the caps. After counterboring the parts are again washed. The teeth on the guard are cut on the Gillette Safety Razor sawing machine shown in Fig. 14. The guards for the saws and gearing have here been removed for purposes of illustration. The two arbors are geared together, each arbor carrying a gang of 13 saws. The saws, separated by spacing collars, are 2.375 inches in diameter, 0.081-inch thick, and run at 2,400 revolutions per minute. The work seen in position in the figure is located by studs entering the two end holes. As the ram rides up to the saws the work is gripped by the two hook clamps A and is thus held under the tension of the springs B.
Two small rods pass through the ram and project from the face of the work-locating nest when the ram is at the bottom of its stroke, and thus serve to eject the work, which drops down the chute seen to the front of the ram. This operation is conducted at the rate of 1,000 pieces per hour. It is found necessary to re-grind the cutters for between 80,000 and 100,000 pieces.
A third washing operation is here interposed and, after inspection, the guards pass to the end polishing operation already described and illustrated in Fig. 11. The guard, with the principal dimensions, is show in Fig. 15.
The Manufacture of Safety Razors II
October 27, 1927
The Practice of the Gillette Works, Ltd., Slough
Operations on the Handle
The turning, drilling, and threading operations on the handle are conducted on two groups of four and five Brown & Sharpe automatic machines, each group being in charge of one operator. Circular-form tools without top rake are used in the production of the handle extension for both razors and of the ball top for the pocket edition. The various sizes of brass rod used are supplied in 10 and 12-ft. lengths.
Forming the Handle Extension
The handle extension is formed from ???-inch diameter brass rod on a No. 0 Brown & Sharpe high-speed automatic. The stock is fed to a stop, when it is engaged by a combination centring and countersinking tool in the first turret station. Since only three tools are required in the six station turret, spring stop double indexing is employed to bring tools in the third and fifth stations respectively in line with the work.
The second operation consists of drilling through the extension with a No. 19 drill held in the third turret station and simultaneously forming with a circular tool held in the rear slide. The turret is then indexed to the fifth station and the hole tapped 32 U.S.F. The spindle reverses and the work is parted off by a tool in the front slide. The spindle runs at 2,700 revolutions per minute, and the production time is five seconds per piece. This component is shown at W in Fig. 16. The extension for the standard razor differs somewhat from that shown in the figure, being drilled through ???-inch and formed with a small boss at the upper end for assembly with the guard by spinning.
Forming the Ball Top
The ball top for the pocket edition razor is formed on a No. 0 Brown & Sharpe high-speed turret form lathe. Three sets of tools, consisting of rotary stops and 76 tooth knurls, are held in the turret. A combination tool in the front slide parts off the finished work and rough forms the next piece. The work is then knurled from the turret, finish formed by a tool in the rear slide, fed to the rotary stop in the turret and parted off from the front slide. The object of using rotary stops on the turret is to prevent blemishing the end of the finished work.
The spindle runs at 3,600 revolutions per minute, and the work is produced from ???-inch rod at the rate of one piece in 3 1/2 seconds. The component is shown at X in Fig. 16. It will be noticed that both ball top and extension are tapered 0.003-inch in 0.156-inch for assembly with the outer tube of the handle.
Operations on the Outer Tube
The outer tubes for the handle are made from drawn brass shells owing to the impossibility of gripping tube of such light section in a chuck without crumpling. The shells are fed into a hopper mounted on the feed-slide bracket of a No. 0 Brown & Sharpe automatic. The feed-slide latch has been removed and the lugs machined off, while the end of the feed slide has been drilled and tapped to receive the threaded end of the rod A, Fig. 17. This rod actuates the plunger B, which feeds the work from the hopper into a pilot tube passing through the spindle. The work is fed to a stop on the front slide. A double-swing knurl on the turret is then brought forward until the knurls are opposite the correct point on the handle, while a pilot rod between the knurls enters the tube to support it during the knurling operation, and then drops away for the knurls to open. A second rise on the rear-slide cam brings a parting-off tool up to the work. The time for this operation is five seconds per piece. The component is shown at Y in Fig. 16.
The ends of the outer tube are countersunk to facilitate assembly. The operation is performed on the Gillette Safety Razor special machine shown in Fig. 18. The work is fed from a hopper by positive agitation into stations in an indexing drum. The agitation is effected through a slight reciprocating motion of a vertical rod, the end of which is seen at A. Each station is indexed between the two countersinking tools seen in the figure by a plunger to the rear of the machine, which engages in holes in the work-carrying drum. The end of the clamping member is seen at B, and this is carried on an arm oscillating on the shaft C. As each station is indexed between the countersinking tools, the member B moves forward to secure the work against rotation. The machine is entirely automatic in action and maintains a production of 10,000 pieces in 8 1/2 hours.
Operations on the Inner Tube for the Standard Razor
The inner tube of the handle for the standard razor is made from 1/3 1/2-inch rod, and two distinct operations are involved.
The first operation is conducted on a Brown & Sharpe No. 0 high-speed screwing machine. The stock is fed to length without a stop, and is then turned to the finished diameter on the stem + 0.001-inch by a tool in the first turret station, the spindle speed being 2,700 revolutions per minute and the feed 0.008-inch. The turret is then indexed to the second station, and the stem is brought to size by a rolling operation conducted at a feed of 0.012-inch. With the turret in the third position, the end of the stem is finished to length, radiused, and centred by a combination tool. At the fourth turret position the head is knurled. At the fifth position the stem is drilled with a No. 19 drill for tapping, and simultaneously two grooves in the knurled head are formed by a tool in the rear slide, fed to the rotary stop in the turret and parted off from the front slide. The production time for this operation is 14 1/2 seconds per piece.
For the second operation on the inner tube, which is performed on the No. 0 Brown & Sharpe turret forming machine shown in Fig. 19, the work is turned end for end. A magazine feed is employed for this operation, and the work is located on curved pads on the front cross slide, whence it is carried forward and inserted in the chuck by a rod held in the first turret station. The turret is then indexed to bring a ???-inch drill in line with the work, as shown in the figure. This drill opens up the tube to a depth of 0.5-inch, and is followed by drills in the third and fourth turret stations, which carry the depth of the hole to 1.25 inches and to the finished depth respectively. The end of the tube is radiused and finished to length by a combination tool carried in the fifth turret station. The time for the second operation on this component, which is shown at Z in Fig. 16, is 10 1/2 seconds.
Polishing Operations on Caps and Guards
The polishing shop for the caps and guards comprises in all 32 5-h.p. motors of the type shown in Fig. 20, running at 3,000 revolutions per minute. Each motor drives two spindles, which can be adapted to take either one or two buffs. The arrangement shown in the figure is for the polishing of the guards. The under side of the guard is first rough and finish polished on the hard and soft stitched buffs shown on the right-hand spindle. For this operation, the work is held on three short studs on a wooden block. In 8 1/2 hours, 1,000 guards are rough and finish polished on the underside by one operator.
The guards are held in the fixture shown at A in the figure for the polishing of the teeth and ends. One of the handles carries two prongs, on which 28 guards are loaded at a time and held in position by the second handle, which is provided with holes in which the ends of the prongs register. One soft unstitched buff is used for this operation, and the output from each operator is 2,700 guards in 8% hours.
The grinding of the outside radius on the guards is performed on rough and finishing emery dressed felt bobs, similar to those shown in Fig. 21. This outside radius grinding is a highly-skilled operation, since on the perfection and uniformity of the radius the shaving qualities of the razor largely depend. The work is again located on three short studs on a wooden block, as seen at A, and the output by each operator is 3,000 finished parts per 8 1/2-hour day. The bobs used are 8 inches in diameter and two inches wide, to accommodate the width of the work.
The caps are first cut down on the outside on two grades of emery-dressed felt bobs, the work being held on a block of wood with the studs and centre pin locating in holes. The bobs and work-holding arrangements for this operation are shown in Fig. 21. Each operator rough polishes 2,000 caps per day.
Before the final polishing operation the caps are dipped in acid. They are then polished on stitched and soft buffs at the rate of 1,200 per day for the two operations.
On leaving the polishing shop the caps are packed in rack boxes, as seen to the left in Fig. 22, so that the polish is preserved. The guards are packed in layers in flat boxes, with sheets of soft paper interposed between the layers.
Wiring Cap and Guards for Plating
The caps and guards received from the polishing shop are attached to their copper wires, as shown in Fig. 22. Each wire carries five parts, and these are fixed to the wire by a special loop knot, so that on pulling the wire, all pieces except the last one are released. To avoid blemishes on the plated product, the parts must be wired so that they do not touch. The wires are arranged in groups of 20, or 100 pieces, for removal to the plating shop. 6,000 pieces are wired per day by each operator, the work being highly skilled.
Operations in the Plating Shop
On passing to the plating shop, the caps and guards are dipped in hot caustic solution, and are finally scoured with lime to ensure that they are chemically clean. Each wire is then hung separately in the tank, where the parts remain for 15 minutes. They are then dried in a steam-heated oven and unwired.
The handle parts are received in the plating shop direct from the machines, and the treatment of all parts is identical. Fig. 23 shows the method of cleaning the parts. They are placed in large perforated buckets, the one seen in the right of the illustration being in the loading position. When filled, the lid is secured by a clamp and wing nuts. The bucket is then tilted by means of the handles A, and is held in the inclined position by rings which are slid down over the ends of the handles, as seen to the left of the illustration.
In the inclined position the buckets are rotated in the hot caustic solution through worm gearing which is driven by belt from the small electric motor seen in the figure. The agitation of the parts caused by the rotary motion ensures that they are thoroughly cleaned.
Following the washing operation the parts are dipped in an acid vat which is arranged beneath a window with a fan above it to draw off the fumes. Between 3,000 and 4,000 parts are plated at one time in the plating barrel shown in Fig. 24. For the purpose of loading the barrel the supporting shaft A is rotated through worm gearing by means of a crank handle applied to the squared shaft end B. This serves to raise the barrel from the tank to the position shown in the figure. Continued application of the crank handle causes the barrel to swing right over to the rear of the tank where the finished parts are discharged into the chute C. The barrel shaft is rotated by means of the chain seen to the left of the figure.
The sides of the barrel are made of perforated vulcanite. The anodes take the form of flat strips passing beneath the barrel, which is arrested at a definite depth by the stop D. The current passes through the work to the end spokes and hub by which the barrel is secured to its shaft, and thence through the supporting arms. The deposit of silver on the spokes can be clearly seen in the figure.
The parts remain in the rotating barrel for from 40 to 50 minutes before the operation is completed. An alternative and more efficient method of plating the handle parts is also employed. By this method they are rotated in an open-mouthed perforated bucket carried on an inclined shaft and rotated by worm gearing. The open mouth of the bucket avoids the high resistance offered to the current by the perforated vulcanite barrel employed in the alternative method, and in this case only 20 minutes are required to complete the plating operation.
After plating, the knurled portion of the handle outer tube is brushed. For this operation three tubes at a time are threaded on a rod and held against a rotating brass wire brush.
The final plating shop operation on the handle parts is that of burnishing. For this operation the parts are placed in a burnishing barrel as shown in Fig. 25, with a quantity of steel balls of appropriate size, and a soap and water solution. For the outer tube 3/4-inch steel balls are used. 8,000 pieces are loaded into the barrel at one time and the operation is completed in from 1 1/2 to 2 hours. For the handle extensions, of which some 16,000 to 20,000 are burnished in 1 1/2 hours, ???-inch balls are used to conform approximately with the radius of the curved portion. In order that no part of the ball top shall escape the burnishing action these parts are mixed with both ???-inch and ???-inch balls. After burnishing the parts are separated from the balls by sieving. This operation is seen in progress in Fig. 25.
Two main current leads for the plating tanks pass round the walls of the plating shop. Thus the current can be tapped off at any desired point, and any rearrangement of the shop can be carried out with the minimum of trouble and expense.
The daily consumption of silver in the plating shop is some 72,000 grains, or 7.2 lb. avoirdupois.
For the cap and guard of the pocket edition razor nickel plating is employed. Silver plating is, however, used on the handles of both models. The reason for this is that nickel plating is not amenable to polishing by the burnishing method, while an attempt to polish these parts on buffs would result in the knurled portion taking up dirt from the buffs which would be difficult to remove.
After removal from the burnishing barrel the handle parts are dried in steam-heated ovens, and then pass to the final handle assembly. The extensions and ball tops are assembled with the handle in a small bench press, each operator maintaining an output of 3,000 assembled handles per day. The plated caps and guards return to the polishing shop for the final colouring process on soft leather buffs. All silver-plated parts are lacquered before going to the final inspection and assembly. Eight handles are lacquered at one time, being screwed to small projections on a horizontal rod. The parts are dipped in the lacquer and then brushed down to remove drops and bubbles. The lacquered parts are dried for from four to five minutes in steam-heated ovens.
The parts of the razor, cap, guard, and handle are assembled for final inspection before the razors are packed in boxes.
As an example of the rigid system of inspection which is in force, the case of the new improved razor may be cited. Each of these razors is numbered and each is tested for blade exposure when assembled with a perfect blade. Readings are taken with a dial gauge by rolling the feeler of the gauge from the guard tooth over the edge of the blade and on to the cap. The blade exposure thus determined must lie between the limits of 0.002-inch and 0.004-inch. Readings are taken at the ends and in the middle of each side, and are charted against the number of the razor before it leaves the factory.
October 20, 1927
The Practice of the Gillette Works, Ltd., Slough
The Gillette Works, Ltd., Slough, are concerned only with the production of safety razors, the blades being made in Canada from Sheffield steel. The daily output from the factory is 12,000 razors, which gives a time factor per razor of approximately 2 1/2 seconds. The brass from which the razors are made is supplied by the Delta Metal Co. and by McKechnie Bros., Ltd. It is of approximately 66/33 composition and has to conform to a rigorous specification in order that it may stand up to the high speeds employed in the turning and tapping operations. The weekly consumption of brass is five tons.
The factory is well arranged and admirably lighted by means of extensive sky lights in the roof, and the comfort of the employees, of whom some 90 per cent are girls, has been studied in that wherever possible they are provided with comfortable chairs with backs.
In all, three models of razors are made in the factory, and these are known respectively as the new improved, standard, and pocket edition. It is with the production of the two last named that the present article is concerned, and attention is here called to the heading block in order that the difference in the constructional details of the two models may be appreciated. At A the pocket edition is shown assembled, while its component parts are indicated at B, C, and D. The cap B is common to both models with the exception of the fact that in the case of the standard razor a longer threaded centre pin is fitted. Another common component is the knurled outer tube of the handle.
In the case of the pocket edition the ball top E, and the handle extension F, remain as separate components until the final assembly, when they are pressed into position in the ends of the tube after plating. The extension F is drilled and tapped to receive the threaded centre pin of the cap B. The guard D, which it will be noticed in this case remains as a separate part, is counterbored, as seen in the figure, to receive the end of the handle extension on assembly.
The standard model shown at G in the figure also comprises three parts, the cap L, the guard and handle assembly H, and the inner tube K. The handle extension is drilled to clear the threaded centre pin on the cap and is secured to the guard by spinning before assembly with the outer tube. The inner tube K is turned on the greater part of its length to conform with the inside diameter of the outer tube, while the end is tapped to receive the threaded centre pin of the cap.
Operations on the Cap
The material from which the caps are formed is received in the form of extruded brass rod of the correct crescent section. The lower limit on the length of the rods as received is 16.5 inches, the upper limit being 16.5625 inches. The stock is slit to length on a Birkett No. 00 milling machine, as shown in Fig. 1. The automatic feed on this machine has been dispensed with as being altogether too slow for the purpose of slitting. The fixture A is grooved to accommodate the stock, the end of which is seen at B. The stock is fed by hand against a stop and the fixture is traversed by hand beneath the saw by means of the hand lever shown. The work is clamped for cutting by the spring steel pads C, but as the slide is moved back at the end of the cut the curved ends of the pads ride up an inclined surface on the block D, thereby freeing the work, which can be fed forward for the next cut.
The spring steel strip E has a curved pad on its lower side. This pad slides over the work during cutting, and immediately the piece is freed by the saw it is thrown out at the side of the machine. One cut is taken to square the end of the stock, so that in all, eleven cuts are necessary to produce ten pieces. The 3 1/2-inch diameter by 0.056-inch thick saw runs at 2,400 revolutions per minute, and a production of 12,000 pieces in 8 1/2 hours is maintained. The length of the pieces from this operation is 1.5725 ± 0.001-inch.
It is interesting to record that this method of slitting to length is shortly to be superseded. A special machine for the purpose is under construction at the Gillette works. This machine will consist essentially of a rotating drum grooved longitudinally on the periphery to receive the stock, which will be held in position by curved spring clamps. The stock will pass under a gang of saws carried on an arbor, so that all the pieces will be cut from each strip simultaneously. Lateral grooves on the surface of the drum will provide clearance for the saws. This machine will give a minimum production of 10,000 pieces per hour. The pieces are next washed first in hot caustic soda solution, and finally in hot water to remove all swarf and grease. After being dried on a steam-heated hot plate, they are arranged in packs of 10, for the convenience of the operator at the next operation, and inspected.
The next operation on the caps, namely, that of punching three holes to take the locating studs and centre pin, is performed on the No. 20 Bliss press shown in Fig. 2. The press is fed by a magazine, and the punching operation is conducted at the rate of 140 pieces per minute. The magazine feed is actuated through the bracket A, Fig. 3, attached to the ram of the press, and thence through the vertical rods B to the bell-crank lever C. This lever operates the horizontal feed slide D through a connecting link.
The work is located endwise during punching by a spring-controlled latch. To free the work the latch is depressed by the pin A, Fig. 2. The mechanism is so adjusted that the latch is not depressed until the pieces of work in the feed slide are under pressure from the upper cushioning springs on the vertical rods B, Fig. 3. The result is that as soon as the latch is depressed the punched work jumps free, and the latch returns to its original position before there is any tendency for the next piece of work in the feed slide to pass over it.
The work is located sideways between an adjustable stop at B, Fig. 2, and a spring-loaded plunger, since it is necessary that the position of the holes should be held within close limits. The lateral position and centre distance of the holes is checked on the "go" and "not go" gauge, seen at C in the figure, while the distance between the end holes and the end of the work is determined by means of the "go" and "not go" gauge D. The centre distance of the end holes is 1.000 inch ± 0.0005-inch.
After punching, the three holes are countersunk on the Gillette Safety Razor special machine shown in Fig. 4. This machine is automatic in action. The three spindles carrying 60-degree countersinks are reciprocatcd by a cam, while the feed slide A is actuated by a track cam carried on a spindle to the rear of the machine. The spindles run at 2,880 revolutions per minute, and a production of 24,000 pieces per 8 1/2 hours is maintained.
A second washing operation is here introduced, and the caps are then ready for assembly with the studs.
It is convenient here to describe the method by which the studs and centre pins are produced. The studs are made from 1/16-inch brass rod, supplied in 12-ft. lengths, on a No. 00 Brown & Sharpe automatic. A circular form tool on the rear slide parts off the finished work, and at the same time forms the curved end of the next stud, while a tool in the front slide turns the rivet end. The finished stud is then fed forward against a stop, whereupon it is parted off by the rear slide tool while the forming of the next stud is in progress. The spindle speed of the machine is 5,000 revolutions per minute, and a production of 60 pieces per minute is obtained. The limits on the length of the pin are ± 0.001-inch, while on the rivet end, which has a taper of 0.004-inch on a length of 0.13-inch, there is a tolerance on the diameter of 0.001-inch.
The centre pins are turned on a No. 00 Brown & Sharpe form and cut-off machine.
After washing, the studs and centre pins pass to the cap assembly bench. The two studs are first assembled with the cap on a small bench press, the studs being a good press fit in the holes. This work is performed by girls, each of whom assemble the studs in 6,000 caps in 8 1/2 hours.
Before the assembly of the centre pins the studs are riveted on a Townsend bench riveting machine. The studs are located in holes beneath the riveting punch. A chisel-ended punch is employed which is rotated by spur gearing. The punch is reciprocated by its upper end engaging with a number of rollers which are carried in twelve holes equally spaced round the periphery of a vertically-mounted disc. The holes are larger in diameter than the rollers, which are thrown outwards by centrifugal force and deliver blows to the work as they pass over the punch. The disc is run at a speed of approximately 1,300 revolutions per minute, so that blows are delivered to the work at the rate of 15,600 per minute. On this machine 24,000 studs are riveted in 8 1/2 hours.
The centre pins, whether for the pocket edition or standard razor, are assembled in presses similar to that used for assembling the studs, and riveted.
The next operation on the cap assembly is that of threading the centre pin. This is performed on a threading machine made by the Harrison Machine Tool Co. and shown in Fig. 5.
The work is dropped into position in a shaped slot in the block A and rests on the projection B, Fig. 6. The spindle C, Fig. 5, is moved forward by hand to bring the work up to the threading die. Pressure of the work on the die pauses the die spindle, and consequently the double-coned pulley clutch D which is keyed to it, to retire. This brings the clutch D into engagement with the inside taper surface of the rear pulley E, and consequently the drive to the die is taken from the pulley E in the correct direction for threading the die on to the work. To disengage the work from the die it is merely necessary to draw back the spindle C. This withdraws the pulley D from engagement with the pulley E and causes it to engage with the pulley F rotating in the opposite direction so that the die is unscrewed from the work.
Fig. 6 shows the arrangement whereby the finished work is ejected. As the spindle is drawn back with the work clear of the die the curved end of the rod G engages with the spindle bearing support. This causes the rod G to pivot about the point H. The rod K and projection B on which the work rests are thereby withdrawn and the finished work drops out. The output for this operation is 7,500 pieces per 8 1/2 hour day.
To remove the slight burr left by the riveting operation a milling operation is introduced. This is performed on the Brown & Sharpe No. 0 plain milling machine shown in Fig. 7 and 8. Two milling cutters, concave ground to suit the profile of the work, are carried on the arbor. The jig used for this operation holds 18 pieces. The loading arrangements are shown in Fig. 7. The clamping pads are raised by the hand levers shown in the figure, and the work is located by studs and centre pins engaging in holes in the jig. The slide is pushed back under the cutters by hand and the automatic feed is then engaged for the forward traverse. As each pair of caps passes under the cutters they are clamped in position by spring pressure owing to the rollers, seen in Fig. 8, being depressed as they pass under the projecting plate A. It will be observed from Fig. 7 that the clamp securing the first 10 pieces can be raised for unloading and loading while the remaining pieces are passing under the cutters. This operation is completed on 8,500 pieces in 8 1/2 hours.
The No. 19 Bliss press shown in Fig. 9 is used to trim the edges of the cap. The work is located on the die by means of the end studs and centre pin. Before the press can be tripped by the lever A it is necessary that the lever B shall be depressed: as an additional safeguard a Broughton guard is provided. It will be noticed that the press is inclined, the finished pieces sliding off the die plate into the collecting box. The production from this operation is 7,500 pieces in 8 1/2 hours. To remove the burrs set up by the press in the last operation two filing operations are introduced. At the first of these the cap is located in three holes and pressed down by hand while two small curved files are reciprooated beneath the ends. This operation is conducted at the rate of 10,000 pieces in 8 1/2 hours.
The second filing operation is performed on the filing machine shown in Fig. 10, which is a Gillette Safety Razor special machine. The work is placed in position, as shown, locating in three holes, and is pressed down by hand on two files which reciprocate beneath the edges. Pressure on the bar A causes the vertical rack seen in the figure to rotate the spindles carrying the files through spur gears meshing with it. The files are thus constrained to move up round the sides of the work so that the upper corners are rounded off. On this machine 7,000 pieces are dealt with in 8 1/2 hours.
After inspection, the caps pass to the machine, shown in Fig. 11, where the ends are polished. This operation is common to both caps and guards. A rotating drum carries the work between two emery-faced buffs. Guards and caps are loaded on the drum alternately by two girls standing at either side of the machine. The guards are located on short pegs, and the caps in holes in the drum, and the work is secured by a spring clamp as it passes between the buffs. The drum makes one revolution in 30 seconds, during which time 32 pieces, or 16 of each sort, are completed.
The end polishing concludes the machine shop operations on the caps, which then pass to the polishing and platingshops. The component and principal dimensions are indicated in Fig. 12, the cap shown being that for the standard model.
Operations on the Guard
The guard, which is also formed from extruded stock of appropriate cross section, is slit to length on the milling machine shown in Fig. 1. A second fixture is substituted to accommodate the altered section of the stock, which is in 12-inch lengths, from which seven pieces are cut in eight strokes, otherwise the operation is identical. After being washed the parts then pass to the machine shown in Fig. 13, which was made especially for the Gillette Works by the Liberty Machine Tool Co. The operation here involved is that of rolling the trade mark on the underside of the guard. The work is fed from the magazine by a cam-operated feed slide. The motion of the feed slide causes the spindle A which carries the roller stencil to oscillate through the agency of the spring-tensioned chain seen in the figure. Thus the trade mark is rolled on the work during the forward movement of the feed slide, and during the return stroke the roller returns to its initial position. On the forward stroke the work passes under the rounded end of a pivoting hook-ended latch B. This latch drops behind the work at the end of the stroke, and as the slide recedes the work is prevented from being carried back, and drops into a chute in the machine bed. This operation is performed on 24,000 pieces in 8 1/2 hours. The holes in the guard are pierced on the Bliss press shown in Fig. 2, this operation being the same as that of piercing the caps, with the exception that the holes are a clearance fit for the studs and centre pin on the cap.
To accommodate the handle extension on assembly the centre hole in the guard is counterbored on the lower concave side. Before this operation the pierced guards are inspected, and then pass to a machine identical with that shown in Fig. 4. A small end mill is carried on the central spindle, and an extension of the spindle pilots in the hole to ensure the concentricity of the counterbore. The output from this operation is the same as that for the countersinking of the caps. After counterboring the parts are again washed. The teeth on the guard are cut on the Gillette Safety Razor sawing machine shown in Fig. 14. The guards for the saws and gearing have here been removed for purposes of illustration. The two arbors are geared together, each arbor carrying a gang of 13 saws. The saws, separated by spacing collars, are 2.375 inches in diameter, 0.081-inch thick, and run at 2,400 revolutions per minute. The work seen in position in the figure is located by studs entering the two end holes. As the ram rides up to the saws the work is gripped by the two hook clamps A and is thus held under the tension of the springs B.
Two small rods pass through the ram and project from the face of the work-locating nest when the ram is at the bottom of its stroke, and thus serve to eject the work, which drops down the chute seen to the front of the ram. This operation is conducted at the rate of 1,000 pieces per hour. It is found necessary to re-grind the cutters for between 80,000 and 100,000 pieces.
A third washing operation is here interposed and, after inspection, the guards pass to the end polishing operation already described and illustrated in Fig. 11. The guard, with the principal dimensions, is show in Fig. 15.
The Manufacture of Safety Razors II
October 27, 1927
The Practice of the Gillette Works, Ltd., Slough
Operations on the Handle
The turning, drilling, and threading operations on the handle are conducted on two groups of four and five Brown & Sharpe automatic machines, each group being in charge of one operator. Circular-form tools without top rake are used in the production of the handle extension for both razors and of the ball top for the pocket edition. The various sizes of brass rod used are supplied in 10 and 12-ft. lengths.
Forming the Handle Extension
The handle extension is formed from ???-inch diameter brass rod on a No. 0 Brown & Sharpe high-speed automatic. The stock is fed to a stop, when it is engaged by a combination centring and countersinking tool in the first turret station. Since only three tools are required in the six station turret, spring stop double indexing is employed to bring tools in the third and fifth stations respectively in line with the work.
The second operation consists of drilling through the extension with a No. 19 drill held in the third turret station and simultaneously forming with a circular tool held in the rear slide. The turret is then indexed to the fifth station and the hole tapped 32 U.S.F. The spindle reverses and the work is parted off by a tool in the front slide. The spindle runs at 2,700 revolutions per minute, and the production time is five seconds per piece. This component is shown at W in Fig. 16. The extension for the standard razor differs somewhat from that shown in the figure, being drilled through ???-inch and formed with a small boss at the upper end for assembly with the guard by spinning.
Forming the Ball Top
The ball top for the pocket edition razor is formed on a No. 0 Brown & Sharpe high-speed turret form lathe. Three sets of tools, consisting of rotary stops and 76 tooth knurls, are held in the turret. A combination tool in the front slide parts off the finished work and rough forms the next piece. The work is then knurled from the turret, finish formed by a tool in the rear slide, fed to the rotary stop in the turret and parted off from the front slide. The object of using rotary stops on the turret is to prevent blemishing the end of the finished work.
The spindle runs at 3,600 revolutions per minute, and the work is produced from ???-inch rod at the rate of one piece in 3 1/2 seconds. The component is shown at X in Fig. 16. It will be noticed that both ball top and extension are tapered 0.003-inch in 0.156-inch for assembly with the outer tube of the handle.
Operations on the Outer Tube
The outer tubes for the handle are made from drawn brass shells owing to the impossibility of gripping tube of such light section in a chuck without crumpling. The shells are fed into a hopper mounted on the feed-slide bracket of a No. 0 Brown & Sharpe automatic. The feed-slide latch has been removed and the lugs machined off, while the end of the feed slide has been drilled and tapped to receive the threaded end of the rod A, Fig. 17. This rod actuates the plunger B, which feeds the work from the hopper into a pilot tube passing through the spindle. The work is fed to a stop on the front slide. A double-swing knurl on the turret is then brought forward until the knurls are opposite the correct point on the handle, while a pilot rod between the knurls enters the tube to support it during the knurling operation, and then drops away for the knurls to open. A second rise on the rear-slide cam brings a parting-off tool up to the work. The time for this operation is five seconds per piece. The component is shown at Y in Fig. 16.
The ends of the outer tube are countersunk to facilitate assembly. The operation is performed on the Gillette Safety Razor special machine shown in Fig. 18. The work is fed from a hopper by positive agitation into stations in an indexing drum. The agitation is effected through a slight reciprocating motion of a vertical rod, the end of which is seen at A. Each station is indexed between the two countersinking tools seen in the figure by a plunger to the rear of the machine, which engages in holes in the work-carrying drum. The end of the clamping member is seen at B, and this is carried on an arm oscillating on the shaft C. As each station is indexed between the countersinking tools, the member B moves forward to secure the work against rotation. The machine is entirely automatic in action and maintains a production of 10,000 pieces in 8 1/2 hours.
Operations on the Inner Tube for the Standard Razor
The inner tube of the handle for the standard razor is made from 1/3 1/2-inch rod, and two distinct operations are involved.
The first operation is conducted on a Brown & Sharpe No. 0 high-speed screwing machine. The stock is fed to length without a stop, and is then turned to the finished diameter on the stem + 0.001-inch by a tool in the first turret station, the spindle speed being 2,700 revolutions per minute and the feed 0.008-inch. The turret is then indexed to the second station, and the stem is brought to size by a rolling operation conducted at a feed of 0.012-inch. With the turret in the third position, the end of the stem is finished to length, radiused, and centred by a combination tool. At the fourth turret position the head is knurled. At the fifth position the stem is drilled with a No. 19 drill for tapping, and simultaneously two grooves in the knurled head are formed by a tool in the rear slide, fed to the rotary stop in the turret and parted off from the front slide. The production time for this operation is 14 1/2 seconds per piece.
For the second operation on the inner tube, which is performed on the No. 0 Brown & Sharpe turret forming machine shown in Fig. 19, the work is turned end for end. A magazine feed is employed for this operation, and the work is located on curved pads on the front cross slide, whence it is carried forward and inserted in the chuck by a rod held in the first turret station. The turret is then indexed to bring a ???-inch drill in line with the work, as shown in the figure. This drill opens up the tube to a depth of 0.5-inch, and is followed by drills in the third and fourth turret stations, which carry the depth of the hole to 1.25 inches and to the finished depth respectively. The end of the tube is radiused and finished to length by a combination tool carried in the fifth turret station. The time for the second operation on this component, which is shown at Z in Fig. 16, is 10 1/2 seconds.
Polishing Operations on Caps and Guards
The polishing shop for the caps and guards comprises in all 32 5-h.p. motors of the type shown in Fig. 20, running at 3,000 revolutions per minute. Each motor drives two spindles, which can be adapted to take either one or two buffs. The arrangement shown in the figure is for the polishing of the guards. The under side of the guard is first rough and finish polished on the hard and soft stitched buffs shown on the right-hand spindle. For this operation, the work is held on three short studs on a wooden block. In 8 1/2 hours, 1,000 guards are rough and finish polished on the underside by one operator.
The guards are held in the fixture shown at A in the figure for the polishing of the teeth and ends. One of the handles carries two prongs, on which 28 guards are loaded at a time and held in position by the second handle, which is provided with holes in which the ends of the prongs register. One soft unstitched buff is used for this operation, and the output from each operator is 2,700 guards in 8% hours.
The grinding of the outside radius on the guards is performed on rough and finishing emery dressed felt bobs, similar to those shown in Fig. 21. This outside radius grinding is a highly-skilled operation, since on the perfection and uniformity of the radius the shaving qualities of the razor largely depend. The work is again located on three short studs on a wooden block, as seen at A, and the output by each operator is 3,000 finished parts per 8 1/2-hour day. The bobs used are 8 inches in diameter and two inches wide, to accommodate the width of the work.
The caps are first cut down on the outside on two grades of emery-dressed felt bobs, the work being held on a block of wood with the studs and centre pin locating in holes. The bobs and work-holding arrangements for this operation are shown in Fig. 21. Each operator rough polishes 2,000 caps per day.
Before the final polishing operation the caps are dipped in acid. They are then polished on stitched and soft buffs at the rate of 1,200 per day for the two operations.
On leaving the polishing shop the caps are packed in rack boxes, as seen to the left in Fig. 22, so that the polish is preserved. The guards are packed in layers in flat boxes, with sheets of soft paper interposed between the layers.
Wiring Cap and Guards for Plating
The caps and guards received from the polishing shop are attached to their copper wires, as shown in Fig. 22. Each wire carries five parts, and these are fixed to the wire by a special loop knot, so that on pulling the wire, all pieces except the last one are released. To avoid blemishes on the plated product, the parts must be wired so that they do not touch. The wires are arranged in groups of 20, or 100 pieces, for removal to the plating shop. 6,000 pieces are wired per day by each operator, the work being highly skilled.
Operations in the Plating Shop
On passing to the plating shop, the caps and guards are dipped in hot caustic solution, and are finally scoured with lime to ensure that they are chemically clean. Each wire is then hung separately in the tank, where the parts remain for 15 minutes. They are then dried in a steam-heated oven and unwired.
The handle parts are received in the plating shop direct from the machines, and the treatment of all parts is identical. Fig. 23 shows the method of cleaning the parts. They are placed in large perforated buckets, the one seen in the right of the illustration being in the loading position. When filled, the lid is secured by a clamp and wing nuts. The bucket is then tilted by means of the handles A, and is held in the inclined position by rings which are slid down over the ends of the handles, as seen to the left of the illustration.
In the inclined position the buckets are rotated in the hot caustic solution through worm gearing which is driven by belt from the small electric motor seen in the figure. The agitation of the parts caused by the rotary motion ensures that they are thoroughly cleaned.
Following the washing operation the parts are dipped in an acid vat which is arranged beneath a window with a fan above it to draw off the fumes. Between 3,000 and 4,000 parts are plated at one time in the plating barrel shown in Fig. 24. For the purpose of loading the barrel the supporting shaft A is rotated through worm gearing by means of a crank handle applied to the squared shaft end B. This serves to raise the barrel from the tank to the position shown in the figure. Continued application of the crank handle causes the barrel to swing right over to the rear of the tank where the finished parts are discharged into the chute C. The barrel shaft is rotated by means of the chain seen to the left of the figure.
The sides of the barrel are made of perforated vulcanite. The anodes take the form of flat strips passing beneath the barrel, which is arrested at a definite depth by the stop D. The current passes through the work to the end spokes and hub by which the barrel is secured to its shaft, and thence through the supporting arms. The deposit of silver on the spokes can be clearly seen in the figure.
The parts remain in the rotating barrel for from 40 to 50 minutes before the operation is completed. An alternative and more efficient method of plating the handle parts is also employed. By this method they are rotated in an open-mouthed perforated bucket carried on an inclined shaft and rotated by worm gearing. The open mouth of the bucket avoids the high resistance offered to the current by the perforated vulcanite barrel employed in the alternative method, and in this case only 20 minutes are required to complete the plating operation.
After plating, the knurled portion of the handle outer tube is brushed. For this operation three tubes at a time are threaded on a rod and held against a rotating brass wire brush.
The final plating shop operation on the handle parts is that of burnishing. For this operation the parts are placed in a burnishing barrel as shown in Fig. 25, with a quantity of steel balls of appropriate size, and a soap and water solution. For the outer tube 3/4-inch steel balls are used. 8,000 pieces are loaded into the barrel at one time and the operation is completed in from 1 1/2 to 2 hours. For the handle extensions, of which some 16,000 to 20,000 are burnished in 1 1/2 hours, ???-inch balls are used to conform approximately with the radius of the curved portion. In order that no part of the ball top shall escape the burnishing action these parts are mixed with both ???-inch and ???-inch balls. After burnishing the parts are separated from the balls by sieving. This operation is seen in progress in Fig. 25.
Two main current leads for the plating tanks pass round the walls of the plating shop. Thus the current can be tapped off at any desired point, and any rearrangement of the shop can be carried out with the minimum of trouble and expense.
The daily consumption of silver in the plating shop is some 72,000 grains, or 7.2 lb. avoirdupois.
For the cap and guard of the pocket edition razor nickel plating is employed. Silver plating is, however, used on the handles of both models. The reason for this is that nickel plating is not amenable to polishing by the burnishing method, while an attempt to polish these parts on buffs would result in the knurled portion taking up dirt from the buffs which would be difficult to remove.
After removal from the burnishing barrel the handle parts are dried in steam-heated ovens, and then pass to the final handle assembly. The extensions and ball tops are assembled with the handle in a small bench press, each operator maintaining an output of 3,000 assembled handles per day. The plated caps and guards return to the polishing shop for the final colouring process on soft leather buffs. All silver-plated parts are lacquered before going to the final inspection and assembly. Eight handles are lacquered at one time, being screwed to small projections on a horizontal rod. The parts are dipped in the lacquer and then brushed down to remove drops and bubbles. The lacquered parts are dried for from four to five minutes in steam-heated ovens.
The parts of the razor, cap, guard, and handle are assembled for final inspection before the razors are packed in boxes.
As an example of the rigid system of inspection which is in force, the case of the new improved razor may be cited. Each of these razors is numbered and each is tested for blade exposure when assembled with a perfect blade. Readings are taken with a dial gauge by rolling the feeler of the gauge from the guard tooth over the edge of the blade and on to the cap. The blade exposure thus determined must lie between the limits of 0.002-inch and 0.004-inch. Readings are taken at the ends and in the middle of each side, and are charted against the number of the razor before it leaves the factory.
List of Figures
- Fig. 1. Slitting Caps to length on a Milling Machine
- Fig. 2. Punching Holes in Caps on No. 20 Bliss Press
- Fig. 3. General Arrangement of Magazine Feed in a Bliss Press
- Fig. 4. Countersinking Holes in Caps on Gillette Safety Razor Special Machine
- Fig. 5. Threading Machine used for Threading Centre Pins
- Fig. 6. Details of Ejector Mechanism used on Threading Machine
- Fig. 7. Jig used in Brown & Sharpe No. 0 Plain Milling Machine for Snagging Rivet Ends
- Fig. 8. Milling Jig showing Locking Rollers
- Fig. 9. Trimming Edges of Caps in the No. 19 Bliss Press
- Fig. 10. Removing Burrs set up by Press Operation on Gillette Safety Razor Special Machine
- Fig. 11. Polishing Ends of Caps and Guards on Gillette Safety Razor Special Machine
- Fig. 12. Cap for Standard Model Gillette Safety Razor
- Fig. 13. Rolling Trade Mark on Guard
- Fig. 14. Sawing Teeth on Guard on Gillette Safety Razor Special Machine
- Fig. 15 Guard for Gillette Safety Razor showing Principal Dimensions
- Fig. 16. Handle Parts for Standard and Pocket Edition Razors
- Fig. 17. Arrangement for feeding Outer Tube Shells on a No. 0 Brown & Sharpe Automatic
- Fig. 18. Countersinking Outer Tube, Gillette Safety Razor Special Machine
- Fig. 19. Second Operation on Inner Tube for Standard Razor, No. 0 Brown & Sharpe Turret Forming Machine
- Fig. 20. Polishing Motor with Spindles set up for Polishing Under Side and Teeth of Guards
- Fig. 21. Bobs and Work-holding Arrangements for Rough Polishing Caps
- Fig. 22. Caps and Guards wired for Still Plating
- Fig. 23. Method of Cleaning Handle Parts before Plating
- Fig. 24. Plating Barrel used for Handle Parts
- Fig. 25. Burnishing Barrel in which Parts are Polished by the Action of Steel Balls and Soap Solution
