Thread: Edge life vrs razor geometry

Is the geometry of the razor ;12-17 degrees likely to impact edge lifespan on razors that go through a past on cloth step? Would you use tape on a razor at the lower end of this range?

Originally Posted by mattnat

Is the geometry of the razor ;12-17 degrees likely to impact edge lifespan on razors that go through a past on cloth step? Would you use tape on a razor at the lower end of this range?

Yes. A razor that is around 12 degrees will not hold up to much.
I would definitely tape such a candidate.
16-17 is fine and should keep an edge decent enough.
It has more to do with the quality of steel and heat treatment.

I restore a lot of well honed razors. Even though some might be restored to near new condition, the hone wear is still there. I always tape the spine to its original thickness. Which can be tricky at times, depending on actual wear.

But I use tape on every razor. Most razors with light to moderate, even hone wear, require only one layer. Two or more for others. Just on a average

Perfect, would you just use the max width of the tang as starting width?
Does kapcom tape resist Wear better than 3m electric?

I’ve had no issues with 3M and thus haven’t tried the Kapton tape. The other thing that seriously can effect the life span of an edge is how much time you spend honing above 8K. The theory behind that is that above 8K seriously thins the area directly behind the apex, and eventually leads to the apex breaking down. Also to avoid this you can micro bevel. The nuances of getting a very sharp edge with great lifespan is wildly debated and requires much experimentation.

Originally Posted by mattnat

Perfect, would you just use the max width of the tang as starting width?
Does kapcom tape resist Wear better than 3m electric?

Yes. Typically there's no hone wear at the shoulder of the spine. That's what I go by.

But you'll get the idea of how much tape and were to put on, just by working with different razors all the time.

General rules of thumb with Tape

Target angle of SRs is 16-17° going back hundreds of years

a 6/8 razor using 1 layer of 3M 700 tape increases the Bevel angle .67° (less than 1 degree) smaller razor more change...

Spine Wear 0-1mm use 1 layer of 3M 700
Spine Wear 1-2mm use 2 layers
Spine Wear 2-3mm Use 3 layers

After 3 layers it can get kinda squishy while honing so make sure the razor is worth the trouble

You CANNOT add steel to the spine (Yes there is a thread on here where I added a new Brass Frameback Spine to a razor) so even if you re-grind the razor you CANNOT change the final geometry with out making the blade smaller.. Math Sucks sometimes

Bevel angle the easy way

Spine thickness/active width X 57.3 degrees = _X_ degrees. remember "Active" width is from edge to where the spine touches the hone

The Magic Marker test is your friend, color the edge of an unknown razor, hone 2-3 strokes see what the hone is touching and what the bevel looks like...

Originally Posted by outback

I restore a lot of well honed razors. Even though some might be restored to near new condition, the hone wear is still there. I always tape the spine to its original thickness. Which can be tricky at times, depending on actual wear.

But I use tape on every razor. Most razors with light to moderate, even hone wear, require only one layer. Two or more for others. Just on a average

I'm skeptical on taping spines. Since if the spine is taped and thus won't worn out with the edge, then the angle get larger and large eventually.

Originally Posted by mrjin

I'm skeptical on taping spines. Since if the spine is taped and thus won't worn out with the edge, then the angle get larger and large eventually.

I’ve seen hundreds of razors with worn spines but never seen a razor with excessive hone wear to the bevel over time because the spine was taped.

Originally Posted by mrjin

I'm skeptical on taping spines. Since if the spine is taped and thus won't worn out with the edge, then the angle get larger and large eventually.

Eventually being the operative word, I don't think you're likely to ever see that.

Hone wear can happen very fast, I got a Gold Dollar to play with and those things have some big ol spines so i honed it without tape with the intent of wearing the spine, omg it happens fast on 1K.

Trust the guys that really know what their talking about, if they say tape you should listen, they will only say it so many times.