Thread: Zowada Website - double bevel info. updated

Originally Posted by Ashley

I had to go back to the DMT 1200 so I thought that I'd have a go at doing the double bevel. I seem to have the razor popping hairs better than before so it is looking good. I'll test shave tomorrow and see how it goes.

Ash.

Ok, I think I like this technique. I'm no master honer, but I can get a blade sharp enough to shave. I'm also new to straight shaving (about 3 weeks now)

I had to do this twice, the first time I don't think I spent enought time restoring the edge from the chips and polishing it out before I did the second bevel. The test shave was ok, but no better than I normally get.

I went back to the hones and started again, this time it spent alot of time polishing on the Belgium Blue then the yellow. Once I was happy with the polish on the bevel, I added the extra tape and did 20 laps. Stropped it about 100 times and shaved with it this morning. I'm pretty happy with it!

I think I like the feel of a layer of tape on the spine when I'm honing, I can't expain it, but it feels smoother and I think I get a little better control of the blade. I'll be using 1 layer of tape on the spine from now on then going to 3 layers to add the second bevel.

Just thought that I would update you all.

Oh, and Tim, thank you again for this technique and you make wonderful looking razors, If only I could justify one.. *must.. suppress... RAD...*

Ash.

Originally Posted by toolarts

James,

The reason is because the number of strokes you hone depends on the AREA of the bevel you are working on.

The number of strokes goes up as a square of the dimensions, so if you double the width of the bevel, you can easily multiply by 4 the number of strokes needed.

By taping, you tip the razor up and are contacting a much smaller area of the bevel, which means the honing goes orders of magnitude faster.

Interesting. So am I to understand that technically this could drastically reduce the time needed to hone to a sharp edge an old wedge with a huge bevel? Like I could hone it traditionally until I get to a certain point, then add two pieces of tape and finish it in less time than normal? Would you do this for most of the honing on a wedge if the bevel is so drastically wide? i.e. you would just be trying to create a smaller bevel which would be easier to hone? Or would it be the same as described on Tim's page? Like only a few strokes after you finished with your finest hone? Sounds like a great system either way.

I feel "all a buzz" with this post, because it seems like a breakthrough in straight razor honing is starting here. Also, it's totally cool and reassuring to me that the age old technique of putting a micro bevel on a cutting tool (e.g. wood chisels, plane irons) also seems to be able to apply to razors.

When I joined SRP last year and started looking at posts, I really wondered why there was no talk of micro bevels or if there was, it seemed the little I did find on it was that you do NOT want a micro bevel on a razor's edge (with no real explanation why from what I recall).

I am going to try this, but not quite yet. For the first time, tonight I got one of my razors sticky sharp and passing the HHT on the Belgian blue and pretty much passing it on the yellow coticule. I can't wait to shave with it tomorrow!

Anyway, with this micro bevel stuff, seems we can learn from our woodworker brothers.

We'll all have to report our findings on how TOUCH UPS go with a micro bevel. Woodworkers do one of two things: 1) remove the micro-bevel by dropping back down to a lower "back bevel" angle, then put a new micro bevel on. 2) Or just do a few passes at the same micro bevel angle and see if that is sufficient. Option 2 gradually increases the micro bevel which eventually requires going back to option 1.

Originally Posted by Philadelph

Interesting. So am I to understand that technically this could drastically reduce the time needed to hone to a sharp edge an old wedge with a huge bevel? Like I could hone it traditionally until I get to a certain point, then add two pieces of tape and finish it in less time than normal? Would you do this for most of the honing on a wedge if the bevel is so drastically wide? i.e. you would just be trying to create a smaller bevel which would be easier to hone? Or would it be the same as described on Tim's page? Like only a few strokes after you finished with your finest hone? Sounds like a great system either way.

No it will not drastically reduce the amount of time that it takes to hone a razor. You must get the first bevel very sharp (at least 8K sharpness) and before adding the second layer of tape; getting the first bevel sharp can still take a long time.

Originally Posted by Philadelph

Interesting. So am I to understand that technically this could drastically reduce the time needed to hone to a sharp edge an old wedge with a huge bevel? .

Yep!

You DO have to hone that bevel--it has to be somewhat close, and you can't have any big gaping chips.

But I found that the real problem with these big fat wedges is that final bit of polishing necessary to get an edge shaving smoothly.

Instead of having to remove metal all along that fat bevel, you just remove a little metal right at the tip. It goes extremely fast. I had been working on this wedge with it's nearly 1/4" bevel for days and making no progress.

Then I taped it, and a few strokes on the 8K and a few more on the coticle and WOW! done!

For the first time, I can see improvement at 100K under the microscope!

But, the downside is that you may have to strop with the tape on, and stropping with tape on the bevel sucks.

I think with a single layer of tape, you can probably remove the tape and still get a decent stropping, but my impression from my work here is that two layers is thick enough to lift the edge a little too far away from the strop.

Perhaps I just need to adjust my stropping technique a little, I'm not sure yet.

Maybe Tim or someone else has some experience with this.

I may fall back to one layer of tape and see how that works. It should be similar, just not as dramatic. Probably have to get a lot closer to a sharp edge first for one layer of tape.

Originally Posted by toolarts

I had been working on this wedge with it's nearly 1/4" bevel for days and making no progress.

Then I taped it, and a few strokes on the 8K and a few more on the coticle and WOW! done!

For the first time, I can see improvement at 100K under the microscope!

That is what I was asking for. I have the same problem currently. This bevel is large and the wedge, fat. I have been working on it for a WHILE but still it is not ready. I was thinking that exactly what happened for you might happen for me. Obviously it is not a given, but theoretically, it seems like it should work.

Honing these big wedges is interesting.

There is physics and mathematics to the honing process--and it is based on area.

I'm pretty sure this means that going to lower grit or increasing the area has a POWER OF 2 affect on the number of strokes.

I am still working on this, but it seems to exhibit itself a couple of ways.

1. As the bevel gets wider you are squaring the number of strokes needed.
2. If you go from one grit to a grit twice as fine, you are squaring the number of strokes needed.

Of course, this is not exact, and there are mutlipliers and differences between aggressive and less aggressive stones, but I think the principle holds.

Going from 1200 grit to 12000 grit without intermediate grits can easily take thousands of strokes, whereas progressing from 1200 to 2400 to 4000 to 8000 to 1000 to 12000 can only take hundreds.

And a bevel that is 8 times as wide can easily take 64 times as many strokes. Think about that. If it takes 40 strokes, you are talking about 3000 strokes.
It takes me about 2 seconds to do a stroke (1 X pattern). Thats over an hour and half, and if you count re-wetting the stone, and probably lapping it in between, this is really 2 hours.

And if it was 80 strokes for a normal bevel, you could easily be talking 6 or 7 hours of stroking a big wide bevel for the same effect.

So, if you tape, you drop that fat bevel back down to the size of a standard hollow ground razor with the factory grind, and you can now use a a few dozen strokes on barber hones to get it shaving.

Anyway, that is the explanation I came to for myself. Try it out, it's pretty easy.

I will concur with this technique on the big wedges, the second bevel really speeds up those last few steps. I've been shaving with a handful of those old fat arse wedges for a few months and the double bevel seems to aid in edge retention, since the angle isn't as acute, it is a bit more stout and will resist dulling a bit more.

I disagree that the edge is sharper using the traditional method though. the edge can only be as sharp as the finest grit used, and the angle difference is not any more than the variation in the thickness of all vintage razors. the angle of a thin backed extra hollow ground razor and a WIDE backed wedge is much greater than the difference created by the tape. so the only side affect that I have been able to detect is a greatly reduced honing time and a slight increase in edge retention (could just be in my head, but the result is surely not negative).

P.S. Tim, KUDOS on those close up shots of different honed edges!!!!! It's great to actually SEE what all the famous hones are doing to the edge in question. But your razors/knives could use some refining...

Originally Posted by Tim Zowada

...
Thanks for your patience with my weird ideas.
...

The idea isn't at all weird. Putting a double bevel on knives is a decades (centuries?) old idea. Still under debate today.

Since the reduced angle doesn't go to the edge, it'll have no effect on the actual cut itself. It might reduce "drag"? One of the knife arguments was that the reduced angle behind the cutting bevel would reduce "drag resistance" when going through meat. I'm hoping my razors won't need that particular advantage.

Two reasons to use it. (IMO)

• Some think a double bevel cuts better.
• You want to touch up an already established bevel, but want to do it quicker by using a steeper angle, without polishing the entire existing bevel.

I tested double-bevels on some fine knives decades ago and came to the conclusion that it was far more trouble than it was worth. It does make touching up an existing edge much faster though.

As far as the angle difference and cutting ability goes; if I put one layer of electrical tape on my 1/8" spine Double Duck, I get a cutting angle virtually identical to my 9/64" spine vintage C-Mon wedge w/o tape (total included angle variation w/in 0.15 degree). Edges so close as to make no practical difference...

Ok, well I'm definitely going to give double bevels a try. One thing I'm curious about is what to do when it comes time to touch up the razor – whether to put three pieces of tape on and hit just the secondary bevel, and if so, how many touch-ups before you have to reset the primary bevel, etc.

I'm also wondering about pasted hangers. I have a linen with chrome oxide that I'm pretty attached to, I do ten or so strokes on every few shaves...I hate the idea of having to put tape on the razor just to give it a few licks on a hanger.