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The Folding Knife (& Switchblade) Forum The materials, techniques and the designing of folding knives. |
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#1
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Heat treat before grinding?
I've always ground my blades pretty close to finished sized before heat treating, but now that I'm focusing on learning how to make folders, I'm using much thinner cross sections of steel. Grinding before heat treat, then grinding again afterward is posing some logistical problems for me, and I end up taking of a tad more material than I really want.
Questions is, for steels like ATS-34 and O-1 in thicknesses of 1/16 and 3/32, is it practical to grind the bevels in after heat treating? Wear on belts aside, that is. I do plan to do spring/tang fitup prior to heat treat still. __________________ Kurt Huhn pipecrafter@pipecrafter.com http://www.pipecrafter.com |
#2
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Kurt, what kind of "logistical" problem do you have with grinding before and after?
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#3
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When I do a clean-up grind after heat treat, I always take a little bit more off than I want, because I tend to go a little closer to final shape prior to heat treat than I should. In 1/16" stock this is embarrassingly easy to do. So what I end up doing is hand sanding after heat treat which takes quite a bit of time.
My thought was: if I grind the profiles to shape; including the lock/spring/tang fitup; heat treat the profiled blades; THEN grind the bevels in, I might be able to spend less time on hand sanding. Foolhardiness? __________________ Kurt Huhn pipecrafter@pipecrafter.com http://www.pipecrafter.com |
#4
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If it works, it's right for you. There are 101 ways to do anything.
I make two blades at once, back to back, so I have a handle while I grind the blades prior to HT. I grind the flats to 220, saw the blades apart, finish profiling the tang, HT, then after HT, just touch the flats to a 220 belt enough to clean up the black, then 320 or 400 belt, then hand sand. I don't actually remove any more material than it takes to clean up the HT. Last edited by Don Robinson; 04-10-2010 at 09:37 PM. |
#5
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Ah, so in other words - practice. That's funny because that's the first thing I tell aspiring pipe makers...
I basically do what you just described (aside from making them back to back), so I'm guessing my trouble might be in my technique. I need to have a lighter touch on the belt it seems. Thanks Don! __________________ Kurt Huhn pipecrafter@pipecrafter.com http://www.pipecrafter.com |
#6
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I know a few makers who grind the profile, HT and then grind the bevels. It works good for them, ceramic belts, lower RPM's, and lots of dunking in a nearby bucket of water. I have yet to do it this way, just a bit paranoid of ruining the HT. When they are done grinding, they hand finish and its done.
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#7
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I have ground all my blades after HT for the last 12 years or so, regardless of how thick the steel is. On really thick blades I may rough grind the bevels but up to 3/16" are ground completely after HT. I started doing this because of warping that I was getting on thin fillet knives when I ground them before the HT.
I do not find belt wear to be excessive, I use one fresh 60 grit ceramic belt per large blade and the belt is still useful for less demanding work afterwards. I would expect to grind several of the blades you are making with one belt. Grind bare handed and there is no chance of damaging the HT since your fingers will complain before you reach 200 degrees..... |
#8
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I heat treat all my folder blades before grinding the bevels. The only exception is when I need to bend the blades to pass other blades in a multi-blade folding knife.
Like it was already said keep everything cool and you will have no problems. Ceramic belts are good and it is tempting to use lower RPM's but the belts wear better and last longer if you use high RPM's and high pressure. I do slow things down as I go through the grits but that's just personal preference. Good luck! Kirby |
#9
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I tend to HT before grinding on blades that are 1/8" thick or less.....especially on something like kitchen cutlery. I will generally profile the blade, then heat treat, then grind the bevels. The up side is that things tend not to warp....any warp in a blade that's 1/8" or less, and has had the bevel ground, usually means starting over because there just isn't enough material to save it. The down side is that you really do have to pay close attention to what your doing!
__________________ WWW.CAFFREYKNIVES.NET Caffreyknives@gmail.com "Every CHOICE has a CONSEQUENCE, and all your CONSEQUENCES are a result of your CHOICES." |
#10
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Well then, it seems I'm the only one who grinds before HT.
My blades never warp because I leave enough of the full thickness spine before HT. That keeps the blades flat during quench because they are placed between heavy steel plates to quench. I remove the foil before quenching. If I have only one blade, as is usual, I balance the blade on the plate by placing a piece of scrap on the other end of the plates. That way I always know the plates are parallel and touching the spine all the way. Different strokes. |
#11
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Thank you all! This is great info - and kind of confirms what I was thinking. I think I'll give it a try next folder and see how it turns out.
Thanks again! __________________ Kurt Huhn pipecrafter@pipecrafter.com http://www.pipecrafter.com |
#12
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Yeah, I started in Alaska grinding after heat treat of blades 1/8 or less. Works fine for me.
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Tags |
ats-34, cutlery, folder, folding knife, heat treat, knife, knives |
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