Why the Bevel’s Angle is Important

[Cwtan12]

I don't like tape. Having said that for normal use you can hone a new razor with tape and will not affect the edge geometry enough to make a difference in a lifetime.

I came across the width of some used razors on sale were very narrow compared to an unused ones. For example a worn looked like a 5.5/8 when a NOS or an unused one of a same model is a 6/8.

If the spine thickness is always the same because the shoulders are always protected with something during honing, I think the bevel angle should be a lot bigger when a 6/8 razor becomes a 5.5/8.

For me, using tape is not much unlike wearing gloves when I am working on something. I most always prefer not to wear them, but sometimes they are necessary.

Under what circumstances tapes are necessary during honing?

Even though I have been shaving and honing using straight razors for years, I don't have much knowledge because until a few months ago, I was experimenting alone without knowing I could ask and find more information from forums like B&B.

 

[Mr.Tee]

If the bevel is too acute to hold an edge, taping it will increace the angle. Or, some fellas just dont want the spine wear on a fancy razor or any razor for that matter. Many diffrent reasons for many different folks. For some reason this topic agitates a lot of people. If you haven’t already, read Gamma’s most recent post, there is a lot of good info there.

 

[Mr.Tee]

Oh, by the way... Experimenting on your own is the best way to learn IMHO.

 

[steveclarkus]

If the bevel is too acute to hold an edge, taping it will increace the angle. Or, some fellas just dont want the spine wear on a fancy razor or any razor for that matter. Many diffrent reasons for many different folks. For some reason this topic agitates a lot of people. If you haven’t already, read Gamma’s most recent post, there is a lot of good info there.

Kind of like not wanting any nail head marks on your new hammer.

 

[Slash McCoy]

Kind of like not wanting any nail head marks on your new hammer.

Well, to be fair, most hammer faces are neither etched nor gold plated.

 

[steveclarkus]

Well, to be fair, most hammer faces are neither etched nor gold plated.

Well, to be fair - I suppose. I'm just jealous because I don't have any pretty razors or hammers. I do have a new Dremel and a half dozen GD66's though.

 

[lightfoot]

After reading Keith’s post I got out a blade that’s been struggling to take an edge. The rough angle is around 14.9. So on went 2 layers of tape & out came the 400 Atoma. After some work and some tape swapping the bevel finally started to narrow down. It’s already cutting arm hair better off the 400 than it was prior to the angle adjustment. But I’m not even close to being done yet. I think taking it from a 5/8 down to 9/16 will hopefully get me in the 16-17 degree range. We’ll have to see. I could rehone it from where I’m at but I think I would only get a few shaves out of the deal. I need to narrow the blade a bit more to get better longevity out of the razor I think.

 

[psfred]

I think this procedure may rescue the maligned Pakistani razors. Just for kicks I got a couple a few years back and have tried to hone one up. Takes forever, and they are very thin, so I suspect they are not intended to be honed on the spine. With some practice, I'm betting free-handing them is the ticket if you want the edge to hold any length of time. Pretty rough too, so a lot of metal has to come off to get a decent bevel.

I'll tape one up someday and see what happens with a fairly normal edge angle rather than the 12 degrees or so (or less) from using the spine as a guide. Very wide too. And quite possibly too soft to hold a real edge. A nice winter day project when I can't get out.

 

[lightfoot]

I think this procedure may rescue the maligned Pakistani razors. Just for kicks I got a couple a few years back and have tried to hone one up. Takes forever, and they are very thin, so I suspect they are not intended to be honed on the spine. With some practice, I'm betting free-handing them is the ticket if you want the edge to hold any length of time. Pretty rough too, so a lot of metal has to come off to get a decent bevel.

I'll tape one up someday and see what happens with a fairly normal edge angle rather than the 12 degrees or so (or less) from using the spine as a guide. Very wide too. And quite possibly too soft to hold a real edge. A nice winter day project when I can't get out.

Please keep us posted on your progress. I tried this on the razor I’d mentioned and it didn’t help at all. That razor had never shaved well to begin with so as a last attempt I increased the angle to see what would happen. Well, what ultimately happened to this razor is something that should have happened a long time ago. I pitched it!

 

[eKretz]

Good post for the most part but one part I don't agree with:

But at the end of the day, width of the edge is the common denominator that must be factored in first and most heavily. Edge width is controlled by bevel angle and only bevel angle.

I agree that edge - or more correctly, apex - width is the most important factor in the effective sharpness of a blade (for the purposes of a "push cut" like when shaving at least), but it has nothing to do with bevel angle. A blade with a 30° bevel can have just as narrow an apex as one with a 10° bevel - in some cases the more obtuse blade might support a narrower apex, but only if the more acute blade can not support its narrow apex without the edge failing. In any case, the more acute the bevel angle the easier hair will cut, but this has to be balanced with edge longevity, like Gamma noted.

Steel is extremely flexible and fragile on the scale we're talking about here - apex width on an extremely sharp blade can be as narrow as 0.1 - 0.15 microns. Hardened steel that is the thickness of a piece of paper is not a whole lot less flexible than that paper - and paper thickness is about .004" on average (100 microns!) so you can imagine how flexible and fragile the steel is at ~1/4000 of that thickness. A fine quality straight razor is just about .004" - .006" thick just behind the bevel for reference.

Also, Feather blades do not have an apex formed of polymer. The blades are simply coated with some material that massively reduces friction, allowing the blade to cut more readily. I spent quite some time spider-crawling the web and old razor blade makers' patents fishing for this info - many of the coatings are composed of teflon mixed with other proprietary ingredients. Most modern blade makers do not share this info as it is considered as a protected trade secret.

 

[bluesman 7]

Also, Feather blades do not have an apex formed of polymer. The blades are simply coated with some material that massively reduces friction, allowing the blade to cut more readily.

If the apex is coated I would postulate that the cutting edge is polymer. Maybe only a molecule thick but......

 

[buca3152]

That's just what we need! Something to coat our blades with one molecule thick. I'm sure we can find a sprayer at harbor freight that can do the job. Lol. Then maybe we could blame the coating and or the spraying technique instead of the angle.

 

[psfred]

Coatings a few atoms thick are quite common. It's called sputter coating (which isn't really what's going on, but that's what it's called). And there is at least one manufacturer who electro-forms diamond-like carbon coatings on blades to restore the apex rather than just coating the honed steel edge. Should make them a bit sharper, but the main reason the diamond-like carbon is there is the reduce abrasion wear. It also reduces edge friction in the same way platinum or chromium coating does.

 

[eKretz]

As far as I'm aware the apex on a Feather is coated but it isn't a sputtered or PVD coating. It's more like a solid lubricant really. It can be wiped away. You can see this pretty easily by attempting an HHT with a new blade. It won't blend. Won't even violin. Wipe the blade clean with acetone or shave with it once or twice and it will HHT like crazy. Most sputtered or PVD coatings are pretty obvious as they discolor the steel. Usually you can see a shade of color or a sort of rainbow shimmer. Those are definitely a different story.

 

[ambrose]

wow amazing read!

 

[Gamma]

wow amazing read!

Holy Blast from the Past Batman.......
JOSE!

 

[Disburden]

Back in the old days when coticule.be was around we used to talk about bevel angles. If you have a really old razor with a ton of wear on the spine, using the calculator is a great way to check your angle.

Hey Jose!!!!

 

[steveclarkus]

My most comfortable razor is a GD66. I find the W series OK and I have a Crabtree & Evelyn Soiigen that had a bent spine that required a lot of honing which resulted in a 12 degree edge - very uncomfortable. I’m in the “if it feels good do it, if it doesn’t, don’t camp”. Excellent post.

I’ve recently acquired a few vintage blades - Sheffield, Soligen and American - the GD 66 is no longer my most comfortable blade.

 

[Lord Fatboy]

Nice one @Gamma , will this info be going on tomonag dot com?

 

[Neurotopia]

Jose sent an email a couple months ago, sounds like he may be thinking of makings strops again. Is that the case??