File thumb slots on spine

Milt

Milt

Joined
Nov 16, 2008
Messages
260
I could use some help in getting the thumb slots on the spine evenly spaced and at a right angle to the spine. How does one layout the file guide lines? I have used both a triangular file and a flat file used on edge.


Milt
 
Someone here once told me to use a thread file. The one I own is square; one end has 12/14/18/24 spacings, the other end has 11/13/16/20. As far as I know, this file is meant to clean out existing threads, not to cut hardened steel. But I've found it very helpful for starting thumb-notches prior to HT, cutting grooves in pins for epoxy to grab onto, etc.

A small machinist's square is indispensable in the shop. I got mine at Menard's, and although it's likely not perfect, I use it a LOT and wouldn't want to be without it. This is only one example where it comes in REAL handy.
 
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Do you file the thumb slots before HT or after. I would think after to keep the chances of cracking down during hardening. Am I correct in this?
 
Before. The blade is too hard to file after HT.

Milt
 
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Brownells checkering file and before heat treating. After heat treating it can be touched up with a 3 sided diamond file. Dont worry it wont crack in the HT.
 
to lay them out and square ,Dye-kem the spine I use a file guide and fine tooth hacksaw blade to start the cut then a pair of dividers to mark the spacing I want , move the file guide cut , then mark for next cut and so on . May be the long way to do it but if I try freehand I always end up crooked .
 
Thanx, I wish I had done that on my last knife. I guess I'll have to try it on my next one. Midway has checkering files for $32. Do you think 20 lines per inch is the best?
 
For a thumb serration get the least LPI they sell unless you want it to be very aggressive. I use the 20 LPI for just about everything.
 
Brownells sells a 20, 25, 30 and even 40 I believe checkering file, I find the 20 to be a little course and the thirty to be about right albeit alittle fine.
Therefore if I were in the market for another checkering file I would probably just buy the 25LPI file and call it good.
Chris
 
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