Thread: How Bevel is Affected by Taping

Originally Posted by icedog

Okay, this may not be news for some. I wanted to know how much the application of a single layer of electrical tape to the spine of a razor you are honing affects the angle of the bevel (as compared to no tape). So I took two measurements on the nine (9) razors I currently own:

1. blade width from the thickest part of the spine(which is what contacts the hone) to the edge
2. thickness of the spine

Then I used the following formula to calculate the theoretical bevel angle (I'm not smart enough to work these computers so I am showing a photo of the formula):

Where (still not smart enough, I insert yet another picture of a picture):

Note: I divided the spine width by two to get the actual bevel angle. Otherwise I would have calculated the included angle of both sides of the blade.

I then ran the calculations as above and added 0.007" (the typical tape thickness or TTT for those that dig abbreviating shit) to O to calculate the angle (theoretical) with tape.

Here's the data Oh my God I'm so stupid! I have to put in another picture):



Conclusions:

• Yes, taping the spine will affect the geometry of the bevel (but DUH Icedog! we already knew that!)
• The narrower the blade, the more it's bevel will be affected by taping.
• I need more big razors
• I really need to get back to work!

So what do you think about that?

Icedog, this is what I think: you're an animal! Kinda crazy too - to go through all that, but a great idea.

I also believe that as the spine wears down, coincidentally with the edge (under normal honing) that the angle remains constant for a correct shaving edge. Can you figure a formula for that? Eh?

Or how about this: (and maybe your above data aready has some of what I'm about to suggest)

Assuming a brand new straight razor, the spine has a certain thickness, blade certain width, equals a bevel of X. That bevel would be the intended thickness for shaving for that razor. Yes? Now add the tape. How far off is the bevel with the tape (I guess that is your Delta above), and how would that affect shaving?

Also a rate equation: under normal honing (define) how long will a straight razor blade last before the edge/spine wear will no longer produce a shaving edge?

All in fun, of course.




Scott