DE razor geometry. A system for measuring aggressive razors.

[Ron R]

Square, Plumb and Level Your USB Microscope
(New & Improved with Frickin Optics and Laser Beams)
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I played around a bit this afternoon with the "optical leveling" idea I had a few days ago. The cheapest and easiest mirror I could think of was an old cd. It's easier to cut with regular scissors than actual glass, and easier to drill too. I'm not suggesting anybody else needs to do this in order to take pictures, I really just wanted to check if it would work. It actually does! I did a pretty good job lining things up by eye, but skew has a larger impact on photo accuracy than megapixels, so I wanted a way to be sure that I don't have any skew. This is a pretty quick and easy way to check. Using the optical leveler to double check for skew only adds a few seconds to the normal 60-90 seconds it takes me to line up a shot. Enough preamble, here's how it works.

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Step 1: Making a Optical Leveler: This part is pretty straightforward. Find yourself an old blank CD-ROM or a Barry Manilow cd. Make it look like PacMan with a pair of scissors. It should look like this.

Step 2: Drill a hole in your Optical Leveler: You'll want to select the smallest drill bit you have for this. Larger drill bits will tend to crack or deform the cd. I used a 1/16" bit. Don't use any pressure whatsoever. The weight of the drill is more than sufficient. Too much pressure will tend to crack or warp the cd. Once you've drilled your hole, hold it up to your face and use it as a mirror. Make sure the reflection of your face is crisp and undistorted like a mirror. My first try, I pushed too hard on the drill and my reflection was distorted. The second try was perfect. It should look like this:

Step 3: Level your USB microscope by eye: Take your time and look at the camera from multiple angles to try and make it perfectly 90 degrees to your backlit platform. I'm using an old ipad as platform because I know it's dead flat, and it has backlighting built in. No turn the your USB microscope on. Check and see how you did. If you did it perfectly, the 4 lights will be perfectly centered in your viewer/picture. Here is how I did:

Step 4: Now level it for real: Use the lights for a guide. When they are perfectly centered in your viewer, you are dead perfect level. Here is what this looks like:

Step 5: Level Your Razor to the Camera: Turn on your iPad for backlighting and put a piece of wax paper down to cut the glare. Put your razor on the wax paper and line up the razor in the viewer by eye. Try to put the camera and the razor on exactly the same plane with the apex of the blade in the center of the viewer/picture. The use of a wedge or two make it easy to dial this in. Ensure as best you can that there is no skew in the picture. Here is how I did. I'm pretty happy with this.

Step 6: Check for level with the Optical Leveler: Now place the optical leveler you made onto the face of the razor. Move the little hole over apex of the blade. Check with the lights to see whether the plane of the razor matches the plane of the razor. The lights will be perfectly centered in the viewer if you did it right. I came pretty close by eye, but you can see the lights are up and to the right:

Step 7: Now level it for real: Use the micro-adjuster knob on your $13 harbor freight indicator stand to center the lights and the apex of the blade in your viewer. That's better!

Step 8: Trade the Optical Leveler for a Ruler: Gently remove your optical leveler, and place your metal ruler on the face of the razor to add scale to the final picture. Do this with an absurd amount of care not to disturb the razor in the slightest.

Step 9: Take the shot: Take the picture with your USB camera

In actual practice, all of this takes about 60-90 seconds after you've done it a couple of times. Obviously you only need to make the optical leveler once. Adjusting by eye is pretty quick because you now that you just need to get in the ballpark. Leveling with the optical leveler is a little fiddly, but pretty quick because it's obvious when you get it right. I dim my USB lights pretty low, because all I care about is the profile, and it brings the USB lights into crisper focus when they're dim. Also, I trimmed my Optical Leveler a bit because I felt it was too wide and that made it harder to balance.

Brilliant + good explanation on how to achieve centering a razor .

 

[Old School TSD]

A Ferrari accelerates much faster than a porsche, though anyone in the know knows a Ferrari can't keep up with a porsche on the track. It can however significantly close the gap on the straight away.
What does all this mean though if your objective is to pick up women? Both will attract a certain type of woman. I prefer a woman that drives a stick, not one attracted by a label.
When I got divorced I dated a woman who wanted me to grow in a beard. I did so, and she loved it. Then I had to ditch her because I missed shaving!
I jest...I ditched her because I found a woman that suited me better. Her measurements had nothing to do with my selection, it was all of the intangibles that added up to a better fit.

 

[Esox]

A Ferrari accelerates much faster than a porsche, though anyone in the know knows a Ferrari can't keep up with a porsche on the track. It can however significantly close the gap on the straight away.
What does all this mean though if your objective is to pick up women? Both will attract a certain type of woman. I prefer a woman that drives a stick, not one attracted by a label.
When I got divorced I dated a woman who wanted me to grow in a beard. I did so, and she loved it. Then I had to ditch her because I missed shaving!
I jest...I ditched her because I found a woman that suited me better. Her measurements had nothing to do with my selection, it was all of the intangibles that added up to a better fit.

I understand your analogy but...Koenigsegg!

 

[Dovo1695]

This is a perfect study in how to use reflectors for fill light. Or maybe a cell phone in flashlight mode. This photo is called high key for a reason! It should be obvious, but the reflector or fill light needs to be aimed at an angle towards the dark area. By increasing the total illumination, the camera will reduce exposure thereby reducing the hotspot. Basically, redistribute the histogram from a mountain on the right to something closer to a hill in the middle.

I know nothing about photography. I don't know what any of that means.

As far as lighting goes, I wasn't too concerned about it. All I really cared about was removing skew as much as possible. I had to dim the USB lights to 10% power because that make the circles made by the led lights crisper. The whole operation depends on centering those lights in the picture as much as possible because this means there is no skew.

The other reason I did it was because I wanted as much contrast as possible between the razor profile and the background to have crisp reference lines for measuring. It doesn't make for a aesthetically pleasing picture to be sure, but it suits the purpose of taking accurate measurements pretty well. Only the 3mm x 3mm area defined by the shave plane is relevant to measurements.

If I had an extra $12,000 for a camera purpose built for measuring/evaluating parts with extreme precision, the image would look like this.

 

[Old School TSD]

I understand your analogy but...Koenigsegg!

Lol! I agree it's a far superior car, but if I'm putting the $ down myself I don't know if I'd buy one of those or the 3 Ferrari's, 7 Porsche's, 2 R8's, and the Lamborghini I could buy with the same $...

 

[Esox]

Lol! I agree it's a far superior car, but if I'm putting the $ down myself I don't know if I'd buy one of those or the 3 Ferrari's, 7 Porsche's, 2 R8's, and the Lamborghini I could buy with the same $...

Superior, perhaps, in the right hands. Funny how comparing razors is akin to comparing cars, and an analogy I've used often myself.

 

[Dovo1695]

Brilliant + good explanation on how to achieve centering a razor .

I think we're talking about the same thing, but just to clarify, this is about deskewing, not about centering. You can be perfectly centered and still have a massive amount of skew that renders the photo useless for measuring. Deskewing requires two things: to be centered on the apex of the blade, but also to have the plane of the camera precisely parallel to the plane of the razor profile. That's all the lights do. They're only used for adjusting the angle of the camera on the x and y axis, not the centering of the camera.

Here is an example. This shot is well centered, but it's so skewed that taking measurements is pointless. If I add the optical leveler, without moving the camera or the razor whatsoever, it tells me that the shot is completely skewed. The angle of the camera is all wrong. I'm skewed horrifically on both the x and y axis. It's perfectly centered though.

 

[APBinNCA]

I know nothing about photography. I don't know what any of that means.

No worries, the shot looks amazing compared to what we thought possible!
I just threw that in there for anybody reading later. You just take a piece of foam board and bounce the ambient light onto the subject if you start getting pixel level artifacts in the dark areas or too much reflection messing with the optics.

 

[Dovo1695]

Neither the final "deskewed" photo from the tutorial/demo nor the intentionally skewed photo above is ideal for measuring. Neither has ideal lighting, and a closer zoom would offer far more pixels in the target area. They do serve to highlight the measurement errors that skewing can cause. I used ImageJ to take the measurements for each picture. The deskewed photo has a blade exposure measurement of 0.05mm. The skewed photo has a blade measurement just barely over neutral that rounds up to 0.01mm.

Open them up in Image J or your application of choice and you'll see what I mean.

I intentionally skewed the photo, by moving the camera angle until the lights were down and to the right. This made it look like there was 0.04mm less blade exposure. I could move the camera angle the exact opposite way and make it appear that the blade exposure was 0.04mm bigger than it actually is. In that picture the lights would appear up and to the left on the Optical Leveler.

Put differently, I could skew the razor to look like it has 0.09mm or 0.01mm, when in reality it's 0.05mm. I'm probably not explaining it well, but the purpose of the "optical leveler" is to prevent this measurement error.

 

[Dovo1695]

I just realized how poorly I was describing what the leveler is supposed to do . As @Ron R was saying, we're just centering the apex and the lens in the picture, and ensuring they're perpendicular to one another.

The apex of the blade must be in the center of the picture, because this is a precondition of having the camera lens perpendicular to it. However, simply having the apex of the blade in the center of the picture doesn't mean the lens is currently perpendicular to it; the lens could be at an angle to the apex. When the "optical leveler" is placed on face of the razor, and the reflection of the LED's are in the center of the picture, it means that the lens is perpendicular to the center of the picture. When the apex of the blade is visible through the peep hole, and that hole is in the center of the 4 LED's, it means the camera lens is perfectly perpendicular to the apex.

That was probably an unnecessary explanation because it's a simple idea, but I may want to revisit the idea at some point in the future, and my prior explantions will likely baffle me.

 

[Ron R]

I just realized how poorly I was describing what the leveler is supposed to do . As @Ron R was saying, we're just centering the apex and the lens in the picture, and ensuring they're perpendicular to one another.

The apex of the blade must be in the center of the picture, because this is a precondition of having the camera lens perpendicular to it. However, simply having the apex of the blade in the center of the picture doesn't mean the lens is currently perpendicular to it; the lens could be at an angle to the apex. When the "optical leveler" is placed on face of the razor, and the reflection of the LED's are in the center of the picture, it means that the lens is perpendicular to the center of the picture. When the apex of the blade is visible through the peep hole, and that hole is in the center of the 4 LED's, it means the camera lens is perfectly perpendicular to the apex.

That was probably an unnecessary explanation because it's a simple idea, but I may want to revisit the idea at some point in the future, and my prior explantions will likely baffle me.

The more inaccuracy's you eliminate the better quality of photograph IMO, Lighting is another issue and you kind of glossed over that also. You have taken some nice macro photo's of what we like to see in such a finite blade. Folks must for sure have to realise that the very tip of the cutting edge of the blade we are talking in millionth's of inch and that is really hard to capture with a USB microscope IMO.
Nick you have really pushed the envelope with USB microscopes and have really learned a lot. Thanks
You could buy a new car for what this very accurate microscope would cost but sure takes the smallest things to a whole new level.
A coated razor blade edge with 50,000 magnification. This might show why stropping is important to straight razor or the old Gem blades.

Have some great shaves!

 

[Dovo1695]

The more inaccuracy's you eliminate the better quality of photograph IMO, Lighting is another issue and you kind of glossed over that also. You have taken some nice macro photo's of what we like to see in such a finite blade. Folks must for sure have to realise that the very tip of the cutting edge of the blade we are talking in millionth's of inch and that is really hard to capture with a USB microscope IMO.
Nick you have really pushed the envelope with USB microscopes and have really learned a lot. Thanks
You could buy a new car for what this very accurate microscope would cost but sure takes the smallest things to a whole new level.
A coated razor blade edge with 50,000 magnification. This might show why stropping is important to straight razor or the old Gem blades.
View attachment 1285540
Have some great shaves!

What I know about photography could fit in a thimble barely visible with a USB microscope. I'm just learning out loud.

The optical leveler was a fun experiment, but I don't think it's ideal for getting the best photograph possible from a USB camera. That's because it only works if you're 40mm above the plane of the razor profile, otherwise you can't see the dots. I think the taking pictures is like firing a rifle; the further away you are, the more small errors in shooting angle matter. Getting closer also means that you have more pixels in the 3mm x 2mm target area defined by the shave plane and gap. Putting the camera as close to the apex as possible yields a better picture for accurate measurements. The optical leveler prevents this. Still though, even failed experiments yield useful info.

My takeaways from the experiment are as follows:

• I can come pretty close to getting the camera perfectly perpendicular to the apex by eye without the "optical leveler"
• Being perfectly perpendicular is more important for accuracy than having more pixels
• The apex of the blade must be centered in the picture
• The camera must be perfectly perpendicular to the apex
• The further the camera is from the blade apex the more deviations from perpendicular affect accuracy
• The shallower the depth of field, the harder it is to evaluate whether you are perpendicular
• Backlighting makes it easier to evaluate whether you are perpendicular to the apex because it compensates for shallow depth of field by creating "shadows" that shouldn't be there whenever the angle is not perpendicular
• Using an Ipad as a platform gives you a level surface with built in backlighting
• Wax paper makes a great translucent light filter
• Setting the camera 50mm above the surface of the iPad with it turned off lets you easily adjust the camera to perpendicular before adding the razor and lining up the shot

 

[Ron R]

I know this is not perfect but it still gets a rough idea on the Legendary Micromatic open comb blade exposure.

Well I got my hobby USB Andonstar 500 microscope out recently on some other razor exposures measurements and learned a few things about how to convert some files to Jpg so I can explain better with photographs.
This razor was bought from a razor lot 2 years ago online at the big Auction house(_bay) and this Gem Micromatic or MMOC had a missing blade stop. So I thought it would be nice to file the missing stop down a little to see what kind of blade exposure we are looking at.
Never seen or heard of the Gem MMOC blade exposure expressed so this will give us a reasonable close ball park figure. As most know when tightening a MMOC it will tend to push the blade forward into the blade stops but when one blade stop is missing it skews it quite a bit. To over come this problem I aligned and crazy glued the blade corner and then snugged the top cap. I Did a Visual afterwards and it worked well for this photo exercise. You can get very close measurements with a photo and so here is what I think we have.
Blade is .009 inch thickness and exposure is 2/3 approximately of thickness or .005 to .006 inch or .140mm which is reasonable for a Mid range razor from my experiences using the Gillette adjustable razor blade exposure chart. The MMOC is considered a mid range> IMO so it kind of reasonable. Good thing this is a hobby and I'm retired and had this broken MMOC around.

Gillette Slim or Fatboy adjustable razor settings chart below.

Have some great shaves!

 

[APBinNCA]

Based on feel, I don't think my bullet tip has any less exposure. This goes a long ways towards explaining some things for me. Thanks for getting this measured!

 

[APBinNCA]

Thinking about this from the perspective of the Gillette adjustable, are we in the pre-stainless era? The reason I ask is that I can get a great shave out of the bullet tip with a new carbon blade and a lot of work. However, the modern stainless blades bite me as soon as I tip the blade in. If most shavers preferred 5, give or take, with a carbon blade, would it still be correct to call that medium aggressive with stainless? I consider my Henson medium, 0.05mm, a medium and so do others. That would make the Timeless 95 a medium minus like 3?

 

[Ron R]

Based on feel, I don't think my bullet tip has any less exposure. This goes a long ways towards explaining some things for me. Thanks for getting this measured!

You are correct if steep shaving with most Gem Micromatic variants but how Gem was able to tame a razor a little by changing the top cap configuration to alter blade exposure and where placement or thickness of blade stops are placed IMO.
Base plates are very similar but have different top caps to change exposure.

Have some great shaves!

 

[JPO]

I am getting better results using a mobile phone with a macro clip on lens.
Lupo 95 with astra blade.

 

[jeffmudrick]

I am getting better results using a mobile phone with a macro clip on lens.
Lupo 95 with astra blade.

View attachment 1285731

That's pretty sharp. I'm gonna have to drag out mine for the old Pixel 2.

Sent from my Google Chromebook Pixel (2015) using Tapatalk

 

[Ron R]

I am getting better results using a mobile phone with a macro clip on lens.
Lupo 95 with astra blade.

View attachment 1285731

Very nice photo, click on picture and "open with" click on paint in microsoft and add a few lines will give some details

 

[Dovo1695]

I was curious about lens distortion at the outer corners of my Plugable USB 2.0 razor. I figured the easiest way to check this would be to see how measurements changed across the widest object possible with know increments. I chose a 1mm graph paper for the experiment. I raised the mast height as high as it would go so that I had as many pixels as possible in the picture to maximize distortion.

My theory was that the 1mm squares would get smaller the further from the center I got. I first tested horizontal, vertical, and diagonal in the center of the picture, then I did the same at the two extreme corners. I was surprised to see that there was no change regardless of where I was on the grid. That really surprised me. It's definitely a good thing though. Here is what it looks like: