Spine Thinning?

[Slash McCoy]

I have measured the bevel angle at mid edge length of a few of my SR's. They are:

S.K. Colling Custom = 16.5°​

Ralf Aust 6/8 = 16.3°​

*Gold Dollar W59 = 15.8° & 17.5° (modified)​

*Gold Dollar 208 = 19.5°​

Revisor 6-0035 = 16.9°​

G. Butler Shakespeare = 17.4°​

Puma 1⅝ = 16.8°​

Cadman Bengall 5/8 = 16.1°, 17.1°, 17.5° & 17.4°​

Cadman Bengall 6/8 = 16.0°, 16.9° 15.7°​

*Titan T.H.60 = 18.8° & 19.6°​

*Titan T.H.63 = 18.8°​

*Titan T.H.64 = 19.1°​

*Titan T.H.70 = 18.6°, 19.0°, 18.0°, 19.7°, 18.4°, 19.7° & 18.6°​

Obviously the Asian (*) market is preferring more obtuse bevel angles by about 2°. I'm not sure if @Slash McCoy has some figures for other Gold Dollar models.

All of my SR's have been honed up and are maintained to my high standard of shave-ready. I have found that the Asian made SR's shave just as well as the European made SR's. The Asian made require just a little more pressure tangential to the skin to slice through the whiskers. This is noticed particularly in the fool's pass, my standard edge test that is performed daily. They all shave comfortably and just as closely. I would say that bevel angle is more important if the edge is not as keen as it should be.

Pretty sure I have never seen any GD with a 19.5° bevel angle. Nearly all are considerably less than 19 degrees and as I recall most 208's were just over 18°. The only thing I have personally seen being seriously sold as a razor with a bevel angle of 19.5° was the ZY430 Pro.

 

[Herrenberg]

@Herrenberg, that would have required some work with the much harder steel. Did you measure the resultant bevel angle and how did it shave compared to the old bevel angle?

Thanks for the goad about this razor.

I broke it out again, and took a stubby 8 oz round hammer to the area around the pin. I liked this much better than the long-handled 4 oz hammer I was using before -- I could be gentle and patient, while still getting a sense that something was happening.

The scales do not flop any more, and that made all the difference. I really enjoyed the shave. A very keen edge, and that quality you only get from a rigid blade, where it feels as though you have perfect control, and you get great feedback through your fingers from the hairs cutting. Now I like this razor, again, a lot.

The thinning really helped it feel much more like my other razors. The spine doesn't seem so obtrusive and intrusive any more.

I measure the current bevel angle at 15.18 degrees. I guess I took the spine thinning further than I remembered. But it's all to the good. This razor is going into the regular rotation now, and it's out of the problem group and into the "things I like to shave with" group.

 

[rbscebu]

I got a dual sided 400/1000 off Amazon for lapping. I wish I had seen you mention the bevel angle of the Titans as I have SEVERAL coming and I am not sure how I feel about this news. I am having enough trouble with a razor that has a 17.5 degree bevel. At least I have weeks or months before they show up.

I don't know which model Titans you have coming. This morning I shaved with a Titan ACRM-2 T.H.60. Properly honed and still with the original bevel angle, this SR is very comfortable and forgiving to shave with but has never been as close as my keenest edges. So much so that I have probably been shaving with it using a little too much pressure against the skin.

For this morning's shave, I really concentrated on using the lightest of pressure against the skin. The result was a shave closeness as good as my keenest of edges yet was more comfortable (even with the fool's pass) and still as forgiving.

I think that you shouldn't be worried about their bevel angle. When in doubt, just lighten up. It won't feel like you are cutting whiskers but you are and very close to the skin.

 

[APBinNCA]

I don't know which model Titans you have coming. This morning I shaved with a Titan ACRM-2 T.H.60. Properly honed and still with the original bevel angle, this SR is very comfortable and forgiving to shave with but has never been as close as my keenest edges. So much so that I have probably been shaving with it using a little too much pressure against the skin.

For this morning's shave, I really concentrated on using the lightest of pressure against the skin. The result was a shave closeness as good as my keenest of edges yet was more comfortable (even with the fool's pass) and still as forgiving.

I think that you shouldn't be worried about their bevel angle. When in doubt, just lighten up. It won't feel like you are cutting whiskers but you are and very close to the skin.

Well that razor was a disaster further discussed on another thread, it's fixed now. I am actually back to being fine with whatever angle they come, I will let you do the thinning job first...

They are actually already in Ca and I should have them within days. I think I got a few 60s that you recommended and one 64, I don't even know. I will just touch them up with films and see how they shave.

 

[rbscebu]

This Primus was a square point with a chip near the toe when I got it.
I used the diamond honing block.
I did it dry.
I held the blade like I was scribbling with a pencil so it never got hot.

https://www.badgerandblade.com/forum/attachments/dscn0930b-jpg.1098421/

I have yet another ⅝ T.R. Cadman "Bengall" coming my way within a week or two. This will free up one of my ¾ Cadman "Bengall" SR's. I am considering converting the ¾ Bengall from a Dutch point to an American point, using my diamond plates. If I like the result, I might even convert my other 7 Bengalls to American points.

 

[Slash McCoy]

I have yet another ⅝ T.R. Cadman "Bengall" coming my way within a week or two. This will free up one of my ¾ Cadman "Bengall" SR's. I am considering converting the ¾ Bengall from a Dutch point to an American point, using my diamond plates. If I like the result, I might even convert my other 7 Bengalls to American points.

Ah well then. So you are finally over all that French Metric foolishness, then?

 

[steveclarkus]

Ah well then. So you are finally over all that French Metric foolishness, then?

Wonder how long a metric minute lasts.

 

[Bevel]

I speak metric and imperial so don't really mind which is used. I tend to think "people" in imperial such as 6 foot 2 and 16 stone but use metric for smaller measurements, not really sure why. Metric has some basis in nature though such as a meter being linked to the speed of light so it's hard to argue against it.
Why is 9mm used for guns but imperial for most other things?

If I like the result, I might even convert my other 7 Bengalls to American points.

It would seem a shame to convert historical items to something they weren't meant to be. Kinda like painting shades on the Mona Lisa (ok, not quite that bad) I'd just buy American points from now on if I liked them that much.

 

[rbscebu]

.... I'd just buy American points from now on if I liked them that much.

Unfortunately it is very rare to find an original American point Bengall in the Antipodes.

 

[rbscebu]

I now have everything together. The SR for this project is a Titan ACRM-2 T.H.60 with a steel hardness of about 60 RHC.

​

The spine is currently 6.02mm thick. To get the existing bevel angle down to about 17°, I will need to thin the spine down to 5.20mm. That will mean taking 0.4mm off each side of the spine. This will be done by taking 0.4mm off one side of the spine first and then taking another 0.4mm off the other side of the spine. I have a good vernier caliper for the measurements and I know how to use it.

My tools for this metal removal consist of four 150mm x 50mm diamond plates; 300 grit, 400 grit and 600 grit.

​

My first question that comes to mind is, how do I rub the blade against the diamond plate? I could do it like honing, move the spine up and down the plate lengthways with the spine at about right angles to the plate. Another way would be to have the spine parallel to the plate and move the spine up and down the plate lengthways.

Doing it like honing would make it a little more difficult to get a constant spine thickness along the length of the spine. The other way presents a problem with the blade's shoulders getting in the way.

What are your thoughts on this problem?

 

[Legion]

Ah well then. So you are finally over all that French Metric foolishness, then?

When Bengalls were made the British Empire had not yet seen the light. They say 3/4 on the box. Which actually makes more sense than 6/8, if you think about it.

 

[Bevel]

DrMatt did a video on this at one point for different reasons but the same principles apply.

Before you do anything do a wobble test and write it down, show-side flat, back-side heal wobbles, heal 1/3rd needs reduction etc.
As I said earlier tape the edge with about 4 layers and reduce to 3, 2 and 1 as you close in on the final destination.

The one thing you really need to watch out for is throwing the spine out of alignment with the edge, if you do that you're going to have all sorts of problems fixing it so make sure the taped edge is what dictates the areas of the spine being thinned. This may not be that obvious with 4 layers but will get fine tuned as you reduce to one. Hopefully after that it can be honed as normal.

Again I've said this before but I'd look to use a 3" hone as doing this in sections can only lead to problems and a 3" reduces variables. Think about this before you start.

This would be easier on a straight edge but that razor has a very slight smile so the tape may not reveal the true plane of the edge. You may need to have the exact center touch the tape but when you pinch the tape flat the rest of the edge won't be on the tape, if that makes sense, so if you're doing one side at a time you might want to bend the tape up to conform to the smile and get it off the hone.

Looking forward to seeing how this goes, just take it slowly to begin with.

 

[rbscebu]

Thank you @Bevel. You have given me something to think about. Before I progress, I will report back here on how I intend to approach the project.

The SR I will be working on has an edge length of 68mm and a spine length of 73mm. My 400 and 1k whetstones have a width of only 60mm. If using these whetstones to thin the spine, I don't think that they will present a great problem being slightly narrower than the edge/spine is long.

I am fortunate that the SR only cost me about USD 20 including shipping so no great loss if it is ruined. Doing is the best way to learn.

 

[rbscebu]

Ok, here are my thoughts on thinning this spine.

I did a wobble test on my lapping tile. This SR appears to be free of all distortion. The edge smile is about 0.5mm which it a bit less than I unconsciously produce when normally honing a SR from new.

With taping the edge, I am thinking of applying 5 layers of yellow tape and one layer of black tape. Then I will proceed as follows:

1. Using a 400 grit 60mm wide whetstone, grind 0.1mm first off one side of the spine and the 0.1mm of the other side.
2. Remove the black tape and one layer of yellow tape. Then apply one layer of black tape and grind a further 0.1mm off each side of the spine using the 400 grit whetstone.
3. Repeat step 2.
4. Repeat step 2.
5. Now with 0.4mm removed from each side of the spine, use my 150mm x 50mm diamond plates to round out the spine above the final spine-wear areas.
6. Remove the last of the tape and hone the blade up as normal.

What do you think, am I on the right track?

 

[Bevel]

Sounds like a logically thought out plan. I also think it's wise to go with the 400 grit 3" hone just to eliminate a variable. To be honest with 400 I don't think it'll take that long to do with pressure.

Spend a lot of time on the first 0.1mm to go to dial in how long it takes, time it, and measure regularly.
Once you know, the other side, and the rest, should be much easier and predictable.

Taking 0.1mm of one side and then the other sounds like a good way to keep the two sides even. Where the shoulder meets the tang area is one part you'll need to pay special attention to. I don't know the razor but think about if the spine is to become thinner than the tang how you're going to handle it.
No real reason I can think of not to continue with the 400 grit for step 5?

After step 1, 3 and 4 look down the razor (like in the 3rd pic you posted) just to make sure all's going to plan.
Also check if you're hone remains flat after each stage and lap if required.

Best of luck and take lots of pics to show your progress.

 

[rbscebu]

Thank you @Bevel and will do. Unfortunately a 75mm wide 400 grit whetstone is not really available to me. I am stuck with the 60mm wide stone.

I will probably start this project this afternoon after I have finished my work for the day. Photos as I go.

 

[Slash McCoy]

Ok, here are my thoughts on thinning this spine.

I did a wobble test on my lapping tile. This SR appears to be free of all distortion. The edge smile is about 0.5mm which it a bit less than I unconsciously produce when normally honing a SR from new.

With taping the edge, I am thinking of applying 5 layers of yellow tape and one layer of black tape. Then I will proceed as follows:

1. Using a 400 grit 60mm wide whetstone, grind 0.1mm first off one side of the spine and the 0.1mm of the other side.
2. Remove the black tape and one layer of yellow tape. Then apply one layer of black tape and grind a further 0.1mm off each side of the spine using the 400 grit whetstone.
3. Repeat step 2.
4. Repeat step 2.
5. Now with 0.4mm removed from each side of the spine, use my 150mm x 50mm diamond plates to round out the spine above the final spine-wear areas.
6. Remove the last of the tape and hone the blade up as normal.

What do you think, am I on the right track?

That should work. You can also use sandpaper pinched over the spine, and run the razor in and out through the pinched sandpaper, to restore the flattened spine to roundness. It takes a while, but softly softly, catchee monkey.

 

[Slash McCoy]

Sounds like a logically thought out plan. I also think it's wise to go with the 400 grit 3" hone just to eliminate a variable. To be honest with 400 I don't think it'll take that long to do with pressure.

Spend a lot of time on the first 0.1mm to go to dial in how long it takes, time it, and measure regularly.
Once you know, the other side, and the rest, should be much easier and predictable.

Taking 0.1mm of one side and then the other sounds like a good way to keep the two sides even. Where the shoulder meets the tang area is one part you'll need to pay special attention to. I don't know the razor but think about if the spine is to become thinner than the tang how you're going to handle it.
No real reason I can think of not to continue with the 400 grit for step 5?

After step 1, 3 and 4 look down the razor (like in the 3rd pic you posted) just to make sure all's going to plan.
Also check if you're hone remains flat after each stage and lap if required.

Best of luck and take lots of pics to show your progress.

When I was doing this a lot, I would thin the tang with the belt grinder for the heavy lifting, then use pinched sandpaper to eliminate the look of having been ground on the belt. This results in sort of a negative shoulder, and makes for crazy easy honing thenceforth. I modded quite a few GD66 that way and they were game changers, with a 16 to 17 degree bevel angle, and negative shoulder. Also don't forget to thin the blade at the top bit of the edge bevel. A very thin bevel facet makes a light touch on the hone extremely effective and fast. The more meat you have to remove when honing, the more chances to make a mistake.

A reprofiled heel is the final golden touch when modding a thick spined razor. Then if you like, you can pretty it up with a felt wheel, diamond paste, and a Dremel. Don't forget your eye protection. Just remember that the pretty doesn't shave. The edge does. Pretty is very nice, but it is optional.

When you pass along a GD that has had all that treatment, it never fails to amaze the new owner, no matter how he hones it.

 

[rbscebu]

The start.

Taped the edge with 5 layers of yellow and one layer of black. Next was to measure the spine thickness. I did this at the toe, middle and heel getting results of;

​

Toe = 6.28mm​

Mid = 6.14mm​

Heel =6.08mm​

​

I decided that I would reduce the spine thickness down to 5.4mm along the full length of the spine. Using a lapped 400 grit x 60mm wide whetstone, I got stuck into the grinding. I honed with the blade at an angle so that the full length of the spine and most of the shank was on the whetstone surface.

About 150 laps on each side saw about 0.1mm come off the spine. I paid more attention to the toe end as that needed more steel removed. The new measurements were;

Toe = 6.11mm​

Mid = 6.04mm​

Heel = 6.02mm​

​

Removed the black tape and one yellow, then fitted a new black tape.

It took another 500 laps on each side to remove the next 0.1mm, again paying more attention to the toe end. Measurements came out at;

Toe = 5.93mm​

Mid = 5.90mm​

Heel = 5.91mm​

​

Removed the black and one yellow again and fitted a new black.

Now things started going pear shape. After another 1,000 laps on each side, there was almost no change in the measured thickness. This was going to take forever!

I stopped and had a good think about what was happening. I then realised that I was just measuring the widest parts of the spine cross-section. I needed to round the spine as I was honing so as to measure what I was taking off.

I then decided to give the diamond plates a go. First the 300 grit. I used this with a lot of pressure, rounding the spine as I went. I also found that the more I ground the steel off, the more attention I needed to pay at the heel end, particularly the shoulder and shank areas.

After I don't know how much grinding, I got the spine thickness down to 5.5mm along its full length (with a lot of work at the heel end). I then moved to the 400 grit and 600 grit diamond plates to tidy things up a bit. The measurements are now;

Toe = 5.42mm​

Mid = 5.38mm​

Heel = 5.44mm​

​

Here it what I have now:

​

I will now move back to the whetstones and start to tidy things up.

 

[rbscebu]

It only took a few laps on the 400 grit whetstone to remove the scratches from the diamond plates. I then finished the tidying up using a 1k whetstone. The finish is now just like the original, except I now have a thinner spine.

I measured to new theoretical bevel angle and it comes in at 17.3° along the full length. This might be an interesting SR to shave with.

A Sharpie test shows me the normal with these SRs. Rear side is good and face side was honed with the spine lifted. No problem as long as you are aware of it.

Now to set the bevel, refine and finish the edge. If all goes well, I'll be shaving with this SR tomorrow morning.