Heat trreating O-1 for file guide?

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PaMtnBkr

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Dec 31, 2009
Messages
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Hi Folks,
I am in process of making some file guides from 1/2"x1/2" O-1 steel and will be heat treating after they are fabbed up. My question is, what would you suggest for heat treat since these are substantially thicker than most blades? Also, I assume I will want to temper them back a bit so they do not snap when I clamp them down on a blade? I will be attempting to do this heat treat in my gas forge which has a muffle on it. Any suggestions? Thanks, Don
Yes, I know, "buy Bruce Bumps guides!" I will one day, but I like making my own stuff in the meantime!
 
I did my first one in 1/4"x3.8" O1. O1 is deep hardening, so it should be fine with a proper volume of quenchant. I tempered mine at 300f for 2hx2, and it worked well for nearly a year. A friend was over grinding a blade and he clamped it unevenly and cracked it. I used it for nearly a year without problems, so it was user error, not a steel problem. I already ordered a Bump guide, so I am fine now.
 
I used some 1/4" W2 for the file guide I made. I did the same as Willie. I like the fact that the W2 is shallow hardening, so they should be really really tough. They bend like crazy when I tighten them up (I made it a little longer than necessary I think), so when I torque the two cap screws down, I always say a prayer they don't crack. When I made my first file guide....I didn't temper it at all. What an idiot move that was. SSSSSSSNAP!!!
 
Make sure you use pins and not just bolts to keep it square. With the bolts I was always out a few thousandths from side to side.
 
Two thoughts, what happens if you just use a piece of steel, then use a file with a safe edge (edge ground off).

Or alternatively use a vise to hold the knife vertically (some mill vises will do that). Then idex in some chienses 1/2 x 1/2 HSS bits, those things are cheap, and hard. Makes sense to buy one if you are doing a lot of knives of course.
 
I got my Bump guide today, and its PERFECT in every direction. Worth every penny. I just couldn't afford it last year. On the one I made, I used three holes for bolts. On bolt on one end, and 2 bolts on the other end about 1/2" apart. It came in handy for different width blades.

Re: the mild steel: its better than nothing, but won't help you much on a grinder. I have seen people use plumbing strapping clamped to the blade. Its better than nothing. Carbide and precision milling are the best. Most of us have steel scraps all over, which allows a cheap "beginner" hardened guide.
 
Willie nailed exactly what I was thinking in a few posts above. One thing is for sure about the home made setup like mine,...that just has one socket head cap screw on each end.....they don't line up PERFECT PERFECT. The pins in addition.....absolutely. I can see how Bruce's set up is perfectly square every time you torque it down.
 
With my O-1 file guide,I use one side against the grinder and one side for filing only .The side that goes against the grinder needs truing up all the time. The file side hasn't needed any touch up at all yet.
 
Eric, do you have a plunge on one side only??????

The whole object of a guide it to have perfectly parallel guides on both sides of the blade to get perfect plunge lines.....all the time.
 
Thank you Stacy! I am using hardened guide pins and bolts so alignment should be good. I appreciate the info. Don
 
I am only a hobby maker so for me a Bruce Bump guide would be a dream tool! One day! In the meantime, I enjoy garage shop time and bought a small length of O-1 and still have some left over for other tools or maybe a small blade down the road or a ???
 
Perhaps I should have said edge instead of side .Both edges of my guide are parallel and I mostly use one set of "edges"against the belt and one set of edges to file against when adjusting the shoulders of a hidden tang or something .I have mostly given up on using a file to rectify plunges ,instead I use a method vaguely similar to Nick Wheelers method.I have a 4"x4"x8" block of hard rubber with a small radius along one edge .I put a piece of PSA backed sandpaper on it with the paper going over the radiused edge .
also I use shoulder bolts and ream the holes in the guides to match.
 
Not entirely off topic...
Has anyone come up with a good design that will work on a blade without a riccasso? I keep looking at handscrews, but what modifications would be needed to keep perfect alignment? I'd be making them out of steel of course, with carbide facing....
 
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