integral forged bolster

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if you have an integral bolster with stick tang, how do you access the back side of the bolster to get it flat for some mating piece

fileguide? some fixture for grinding or use files?

thanks
 
I just grind the sides of the bolster flat and parallel to each other so I can clamp my file guide to the sides in order to flatten the back of it with a file. I try to get it close with the grinder before filing. After that's finished you can finish rounding and shaping the bolster to the handle.

I have seen a file guide meant for integral bolsters before with (I think) a square cut out in the center in order to clamp onto the round bolster, perhaps it was from Riverside Machine, not sure though. I've personally never used one.

ETA: I keep the sides of the bolster flat through heat treating and then soften up the back a back portion of bolster with a torch just as I would with the shouders of a regular hidden tang (if it needs it) and then re-attach the file guide and go over it again with a file to make sure it's flat. Using layout dye or a magic marker on the back can help you see your progress. FWIW, I've recently started using EDM stones after "hogging" with a file to help insure the shoulders on my hidden tangs are flat, although it may be over the top it has helped me out.

Edited again for clarity

~Paul
My Youtube Channel
... (It's been a few years since my last upload)
 
Last edited:
I just realized I wasn't all that clear in the way I described my process above, so hopefully it more makes sense now after editing.


~Paul
My Youtube Channel
... (It's been a few years since my last upload)
 
One of the Dutch guys, either Erik Markman or Toni Oostendorp, posted a WIP showing how they use a file guide for the bolsters of what they call "semi integrals" like you are talking about.
 
I was going to make something up similar to that for doing it in the mill. Square block that you could index in the vise like a collet block. Do fronts and backs. Would allow you to do square or radius using the flat or side of the endmill.
 
I've lost it somewhere between the Hospital stays and the mini-stroke, but for the few I've made, I had flattened down an appropriate sized piece of black pipe after heating it up to forging temp, and ended up with a squashed nearly flat piece of pipe I could slip over the tang, and clamp it into the place I wanted to file to. Simplistic but it worked well for me
 
I had to do a search using the internet wayback machine as I noticed they don't have it listed of their site anymore, but here is a picture of the integral file guide that Riverside Machine used to sell, if it helps at all. Same idea as Erik's jig, just basically a file guide with a half round on one inside face to grab the bolster and a hardened steel plate on top.


fileguide.jpg



I know it has 3 points of contact with the half round on only one of the insides, but I would think that having a half round on each side (or actually maybe even a right triangle on each side to form a square) to make a complete circle in the center would be better than having it on one of the sides, which in my mind seems like it would help secure it even more by giving it 4 points of contact, but I'm not sure as I've never used one. Anyway, just another idea.



~Paul
My Youtube Channel
... (It's been a few years since my last upload)
 
Andreotti, that's exactly what I was thinking of regarding the square cut out in the center which would provide the 4 points of contact, nice to see it that it works.

Erik, I just meant that the Riverside's jig was the same idea as yours in that is has hardened plate on the top that covers all sides of the bolster. I'm curious, have you ever have the blade slip down while filing the bolster in your setup?

~Paul
My Youtube Channel

... (It's been a few years since my last upload)
 
coldsteelburns said:
Andreotti, that's exactly what I was thinking of regarding the square cut out in the center which would provide the 4 points of contact, nice to see it that it works.

Erik, I just meant that the Riverside's jig was the same idea as yours in that is has hardened plate on the top that covers all sides of the bolster. I'm curious, have you ever have the blade slip down while filing the bolster in your setup?

~Paul
My Youtube Channel
... (It's been a few years since my last upload)
Click to expand...
No, never happened. When the bolts ate tight I can not even move it with a hammer.
 
I find when putting a fileguide on the bolster it is sometimes hard to keep it square to the spine. I shape and taper the bolster before filing the back. The edge of the bolster that goes against the handle does not get rounded this way.

For a normal fileguide you need perfectly square and flat sides this works on whatever taper I put in the bolster.
 
In Brasil, we make a lot of integral bolster knives. The most of our file guides are prismatic, for normal blades and integrals. In USA, i don´t see much like this. I think you can make yours.
Sorry about my English.
Best Regards.

a.
 
There´s a sequence of esculpted bolster of a integral knife, made by a brasilian knifemaker.

https://lh3.googleusercontent.com/3...Ofd8m4KQBYoWKsUZybYMpqdzzwGv-Bmm=w429-h761-no
https://lh3.googleusercontent.com/y...X-byiK9wLAeRyDDDDJXitNAQnrcOhwOr=w429-h761-no
https://lh3.googleusercontent.com/b...IM2JRIJwG37k_VOKa7l-yfDb7N5wMXyy=w429-h761-no
https://lh3.googleusercontent.com/6...9mKXvNZq0D-ChLz3-5fZM_vDVBiNesif=w429-h761-no
https://lh3.googleusercontent.com/v...-tbOxi2_qVCpQ7HrYDG2XRIyFrwBtcH=w1152-h648-no
https://lh3.googleusercontent.com/o...VS_GhrKyeZxl9L72RawGhXJbeJ2FHA4=w1152-h648-no
https://lh3.googleusercontent.com/_...3NTmfw9k3aHkF8wEML2D0X4WeuVzP-XB=w429-h761-no
https://lh3.googleusercontent.com/P...9DDb7qd_tpeDDYq3sjOGobJAJnLNHHIk=w429-h761-no
https://lh3.googleusercontent.com/1...n-juEwHl9d0x7BzISqli4daDLsi4pU0v=w429-h761-no
https://lh3.googleusercontent.com/u...U-EtrdDho7uj8NpA5iB2lSNTrSukWtVK=w694-h390-no
 
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