Thread: Bevel

To make sure I have the correct understanding...

A bevel is the change when the blade assumes a angle from the normal plane allowing each side to intersect into a point (edge).

The wider, or higher the spine the greater the angle and the shorter the bevel.

If I use tape when creating a bevel I should use tape for every stone in the progression UNLESS I use a greater amount of pressure while setting the bevel on one stone than I will use on the stones later in the progression. The greater the pressure, the taller (wider) the bevel.

If I were to use the exact same pressure on every stone, the tape should remain on for all stones, or off for all stones.

X-Factor: If using tape and I allow it to wear while setting the bevel, this also needs to be taken into consideration when progressing.

And I thought this was going to be complicated

All correct!

I frequently change the tape while on 1K and 4K because of tape wear.

I generally avoid pressure by dropping down a grit level (down numerically, that is).

Well yes, that is mostly correct. Other things being equal, it is the ratio of spine height to blade width that effects the bevel angle - if you are interested in the trigonometry of the geometry there are plenty of threads to search out. A search on "razor angle" or "bevel angle" should find you a few interesting reads.

Tape basically increases the (spine height)/(blade width) ratio, thus increasing the bevel angle (and narrowing the bevel, other things being equal). If you use it on lower grit stones you should continue to use it as you progress up the grits. However, if you do not use it on lower grits you can use it on higher grits to create a "good" double bevel. "Good" secondary bevels are sub-bevels with a greater angle than the primary bevel or, if you prefer, a narrower sub-bevel.

It is always a good idea to refresh the tape if it wears through and you can see metal. However, the effect of tape on the angle is so minimal that any elasticity in the tape, or wearing of it (without wearing through to show metal) is, IMO, negligible and not worth worrying about. It has not impacted upon me yet - put it that way.

You should not be using so much pressure on any stone that it is deforming the geometry of the blade. Yes, perhaps more pressure is used at the bevel setting stage, but this pressure should never be enough to bend a razor to the point where the bevel angle is impacted. Think of it more as torquing the blade so the side of the bevel hits the stone evenly.

James.

I only change the tape when it wears through, like Jim said. However, I do find different tapes wear at different rates; the last one I got was pretty cheap and it wore really quickly...

I couldn't see the point in not using tape for a later progression stone and using more pressure, it sounds a bit iffy to me and will result in some spine wear. The main reason I use tape is to reduce spine wear, and because most razors I get have been honed using tape (generally I ask the seller) and I can't be stuffed re-setting the bevel all the time.

That makes a whole lot of sense to me.

It seems that the ability to actually see and "read" the bevel through all stages of the progression will allow me to eventually produce the optimum edge for shaving and longevity between honing sessions.

Learning to read the bevel correctly is going to take time.

Some of that is more complicated than it would seem.
1. You seem to have a good enough understanding of what a bevel is on a razor.
But just to be sure, the cutting edge of a razor is the intersection of two planes with the relationship of the width of the spine and the distance from the edge to the spine, determining the angle. The bevel is either of those planes.

2. The width of a bevel is influenced by the thickness of the razor near the cutting edge, the width of the spine, and the distance from the edge to the spine.

3 & 4. In many of glens posts he has noted how little effort it takes him to change a razor from one layer of tape to no tape. but for me it seems to take longer. After all everything is a spring. Changing the top layer of tape between stones is generally advised. Adding an extra layer of tape when going to a finisher is often mentioned.

5. If the tape wears unevenly the spine may have some bend in it and adding a layer of tape over that worn layer is a good idea.

6. You thought right, but it is not all that hard if you take small steps.

Jonathan

PS Slow Draw Beat by FOUR

I'm extremely interested in learning to hone correctly. I do best at learning when I can assimilate all of the various pieces into one big picture in my mind. Not just what parts do, but how they function together. The abundance of information and knowledge here is amazing, as well as the willingness and good spirit that everyone seems to follow like an SOP.

What makes it more interesting is that there seems to be quite a few ways to skin the cat.

Now if I could only acquire hand/ eye coordination...

Glen (gssixgun) taught me to hone via his YouTube videos - thanks Glen
Might I suggest that you watch all of them and have a go.

Oh, hone correctly? You should have said! It is an algorithm:

Code:

for (i in 1 to Hone_types){
   set test = 0;
   while (test !=1){
      edge = Rub razor on stone[i];
      test = assess[i](edge);
   }
}

Hone_types is a counter for the stone progression you will use (stone[1] is a 1K bevel setter, stone[2] is a norton 4K, etc, for example);
assess[i] is an array of assessment tools, which depend on the stone used. Generally for i>4 assess[i] are similar.

The tricky bits are the rubbing and the assessment. Apart from that honing is a doddle!

James.

Sometimes putting things into real numbers help you realize that sooner or later you have to rub steel on rocks of some sort evenly until the two sides of the bevel meet into one very feaking sharp edge that hopefully is smooth on the face too..


After quite a few people took the time to do quite a bit of measuring, we found razors that were shaving with bevel angles ranging from about 12 degrees to about 25 degrees.. these were shaving just fine

Then more measuring,, and you come up with and angle change for a 6/8 razor with one layer on 3M #700 Electrical tape of about .60 degrees.. This gives a huge margin of error to play with..

More measuring and testing found that the mean angle for razors by a large margin was about 16 degrees

More testing and measuring found that Taping a spine does in practice change the original angle but it changes it at such a small degree that it will take lifetimes to effect the edge..

Bad honing technique effects the bevel angle much more then taping a spine will, because of excessive spine wear


What did all that testing prove, Tape if you want, don't tape if you want, but if you use tape change it often and apply it evenly