Recommendation? Kamisori questions

J

Justin W

Joined
Jul 30, 2019
Messages
202
I am planning to make a batch of Kamisori, mostly because a bar of steel will probably support 4 profiles and I have no other desire to use steel that thick for anything else atm. So, I can mess a few up, and still have a few to play with.

So here are the questions.
1. Is AEB-L a good steel for this purpose, or is warping too much of an issue?
2. Is it stupid to grind at all pre ht?
3. Planning 62-63 RC unless that is stupid?
4. Planning 0.196" stock. Right hand grind with a 6.5" dia hollow Ura side (0.8" total width grind) and a 2.5" dia hollow Omote side (0.6" width grind, leaving 0.2" at the spine). Approximate angle is 18 deg. Sound like a good profile?
4. Is this a really bad idea to grind without speed control? I don't mind hand sanding a bit to final dimensions, but this could be significant given the edge will be about 10-15 thou or less for considerable length near the edge.

Thanks for any help!
 
Justin W said:
I am planning to make a batch of Kamisori, mostly because a bar of steel will probably support 4 profiles and I have no other desire to use steel that thick for anything else atm. So, I can mess a few up, and still have a few to play with.

So here are the questions.
1. Is AEB-L a good steel for this purpose, or is warping too much of an issue?
2. Is it stupid to grind at all pre ht?
3. Planning 62-63 RC unless that is stupid?
4. Planning 0.196" stock. Right hand grind with a 6.5" dia hollow Ura side (0.8" total width grind) and a 2.5" dia hollow Omote side (0.6" width grind, leaving 0.2" at the spine). Approximate angle is 18 deg. Sound like a good profile?
4. Is this a really bad idea to grind without speed control? I don't mind hand sanding a bit to final dimensions, but this could be significant given the edge will be about 10-15 thou or less for considerable length near the edge.

Thanks for any help!
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Aeb-l at that hardness should work great. That steel was developed for razors. I’d grind all post ht, aebl grinds really easy and you’ll be able to control warping more during the grind. I don’t find that aebl warps badly, or atleast with a carbide peening hammer it’s very easy to correct. When I do chisel grinds I typically pre warp my blade but something that short with grinding the ura on the back side shouldn’t be to troublesome to just start with a straight piece and grind both sides. As for the other questions I’d say try it and see how it shaves, if I was making a straight razor I’d be shooting for .002-.005 thou before sharpening which might be challenging with a fixed speed, just use fresh belts especially getting close to thickness and high grit belts.
 
Justin W said:
4. Is this a really bad idea to grind without speed control? I don't mind hand sanding a bit to final dimensions, but this could be significant given the edge will be about 10-15 thou or less for considerable length near the edge.
Click to expand...
Take your time and don't go to too fine a grit. Coarser grits seem to keep more of the heat in the removed material, finer grits seem to put more heat into the blade. You may have to hand sand from 120 grit upwards
Or get a mist coolant system
 
Justin W said:
I am planning to make a batch of Kamisori, mostly because a bar of steel will probably support 4 profiles and I have no other desire to use steel that thick for anything else atm. So, I can mess a few up, and still have a few to play with.

So here are the questions.
1. Is AEB-L a good steel for this purpose, or is warping too much of an issue?
2. Is it stupid to grind at all pre ht?
3. Planning 62-63 RC unless that is stupid?
4. Planning 0.196" stock. Right hand grind with a 6.5" dia hollow Ura side (0.8" total width grind) and a 2.5" dia hollow Omote side (0.6" width grind, leaving 0.2" at the spine). Approximate angle is 18 deg. Sound like a good profile?
4. Is this a really bad idea to grind without speed control? I don't mind hand sanding a bit to final dimensions, but this could be significant given the edge will be about 10-15 thou or less for considerable length near the edge.

Thanks for any help!
Click to expand...
Definitely do the grinding post ht.

Also, for a razor i think you can get away with pretty much maxing out the hardness. It shouldnt see any situations where toughness will be an issue, and it needs to be able to support a very thin edge.

Also. Doing the last bit by hand isnt a bad idea.

I do that with my kitchen knives, because i usually take them down to about 5 thousandths, or under, and it gets too sketchy not having speed control.
 
when i was making then i didnt make them single bevel because of making the shave more tricky one side of the face vs the other. classicly the single bevel razors were used by people shaving others not a person shaving themselves. when you get close to the finish grind tape the spine and start setting the bevel that way as you finish grind you can chase the hone mark to keep it even and thin
 
butcher_block said:
when i was making then i didnt make them single bevel because of making the shave more tricky one side of the face vs the other. classicly the single bevel razors were used by people shaving others not a person shaving themselves. when you get close to the finish grind tape the spine and start setting the bevel that way as you finish grind you can chase the hone mark to keep it even and thin
Click to expand...
This is a going to be given to a barber, so the single bevel nature of it should be appropriate. However, since this one will have an Ura, it isn't exactly single bevel, but closer to an asymmetrical double hollow. I don't think it can be defined like a western wedge, quarter, half, full hollow. I think it will be close to a half hollow, but time will tell.

I currently do 36g ceramic, 60g ceramic, A300 (80g), A160 (120g) on the grinder. I may skip the last belt based on feel. Then I start hand sanding with a 150g EDM stone before going to paper. So far, this process works well for me without having to do a lifetime hand sanding.
 
Justin W said:
This is a going to be given to a barber, so the single bevel nature of it should be appropriate. However, since this one will have an Ura, it isn't exactly single bevel, but closer to an asymmetrical double hollow. I don't think it can be defined like a western wedge, quarter, half, full hollow. I think it will be close to a half hollow, but time will tell.

I currently do 36g ceramic, 60g ceramic, A300 (80g), A160 (120g) on the grinder. I may skip the last belt based on feel. Then I start hand sanding with a 150g EDM stone before going to paper. So far, this process works well for me without having to do a lifetime hand sanding.
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I will say. At least normally, the kamisori has an ura on one side, and the other is almost like a single bevel blade with a hira, and a kihira.

Thats not do say you can't make one with two asymmetrical hollow ground sides though. It could maybe make honing a bit different than a normal kamisori
 
the ura is on all single bevel knives and razors more less just to make the flat less a problem to hone. why polish the whole back of the blade if you can just hit the edges. and not change geometry. the amount of grind can not be gauged like western styles but thats fine cause most single bevels are in the "wedge"/heavy grind" nothing close to full hollow or singing hollow. many ground on 48" size range grinding wheels (much lie single bevel kitchen knives are)
 
Finally grinding one of these. This example is a double hollow using ~6 inch diameter wheel on both sides. It is turning out well so far and it is about as thin at the edge as I want to take it on my grinder at about 15 thou. That little dip in the plunge at the tip is due to the stock being a little thinner there, it was the end of the bar not the middle.

Should I hollow the Omote side further using a 2.5 inch diameter wheel? Or just start hand sanding?

https://imgur.com/Yr3bWXg
 
I’d likely start hand sanding as is, 15 thou at the edge is going to be very thick for a razor so I’d start with a really coarse paper or stones to thin the hollow on the bevel side further and try to thin it out. I’d likely shoot for only a few thou before sharpening.
 
Joshua Fisher said:
I’d likely start hand sanding as is, 15 thou at the edge is going to be very thick for a razor so I’d start with a really coarse paper or stones to thin the hollow on the bevel side further and try to thin it out. I’d likely shoot for only a few thou before sharpening.
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I did some hand sanding today and got it down to 10 thou in my progression to 400 grit. I am/was tempted to hone it and see how it cuts. Guess I'll do one more round and see if I can get it under 5 thou first. It feels like it should perform well already at 10 thou, and it has a perfect 400 grit finish on it.

Does anyone have a good source for rattan? I tried some leather cord, and did not like it much.
 
I would think 10 thou is thick for a razor also. I mean my kitchen knives I shoot for 5 thousandths at the thickest. 10 thousandths is like edc knife thickness (a bit on the thick side for something not made by a production company).
 
Try chair and caning sites for rattan.
If you know a custom fishing rod builder, he may have some or give you a source.
 
Blankblank said:
I would think 10 thou is thick for a razor also. I mean my kitchen knives I shoot for 5 thousandths at the thickest. 10 thousandths is like edc knife thickness (a bit on the thick side for something not made by a production company).
Click to expand...

By my math, this thing will be about 17 degrees inclusive angle when honed. The double hollow makes it feel like the edge just disappears between my fingers. I'll bring it down further and try to get it under 5 thou. In use, the tbe will increase over time as edge material gets honed away and the edge angle will increase too. I guess that is just a fact with razors.

I found some rattan on ebay. Its pretty cheap, but I hope the quality is good enough. I'll get about 30 ft of it, so it should have at least one nice section in there, lol.
 
I may be wrong, but I thought Japanese razors had a zero edge...
Am I wrong about that?
 
A.McPherson said:
I may be wrong, but I thought Japanese razors had a zero edge...
Am I wrong about that?
Click to expand...
Yes, traditionally they are wedges. This is kind of a mix between a eastern wedge and a western symmetrical double hollow. Imagine a Yanagi knife with a hollow Ura AND a hollow Omote. The edge is easier to hone since you don't have to polish the full Omote surface (only the edge and spine touch, like a western).

I see your point though, maybe it doesn't need to be thinned since it is supposed to perform like a wedge anyway. I'm not going all the way to zero tbe because that might make the edge profile not straight, and in order to fix it I would need to hone a bunch of material off in order to get a good bevel. Better to leave some thickness than not enough.
 
Cool. I just wasnt understanding what you were going for!

I've always wanted to try making a razor... I might get to it someday! So many projects so little time!
 
Justin W said:
By my math, this thing will be about 17 degrees inclusive angle when honed. The double hollow makes it feel like the edge just disappears between my fingers. I'll bring it down further and try to get it under 5 thou. In use, the tbe will increase over time as edge material gets honed away and the edge angle will increase too. I guess that is just a fact with razors.

I found some rattan on ebay. Its pretty cheap, but I hope the quality is good enough. I'll get about 30 ft of it, so it should have at least one nice section in there, lol.
Click to expand...
Yeah. Thats a good reason to get it as thin as possible when its first made. To help prolong the life before its super thick.

Of course hollow grinds help with that.
 
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