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Joined: May 2003
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A question for any of the EC who also happen to own welders.
Has anyone ever tried to hardface and re-sharpen a new surface to old drill bits? (Augers) I have about 20 old augers and a few self-feed hole augers that no longer have enough metal to re-sharpen. Wondering if anyone has ever done it, or if it worked out well?
Mark Heller "Well - I oughta....." -Jackie Gleason
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Joined: Jul 2002
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I don't know about repair, but if you want a new bit to really last a long time try checking these guy's out. [http://www.diversifiedcryogenics.com/]
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Joined: Jul 2002
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Mark, Just a long shot, but wouldn't the heat from the fusion ruin the temper on the drill?. Or even worse, bend the shaft from heat stresses?. Just my $0.02 worth. Alan Belson would be your man on this one, he knows about things metallic.
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Joined: May 2003
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Cryo dont sound cheap, might be able to buy 5 new bits for the cost of re-tempering one.
As far as re-tempering during the weld - once the new metal is on, I can temper that new metal by a few quick dunks in the sink and be harder than the original metal. Twisting - good point, but doubt I'll notice it. I'm gonna give a few a shot this week end - I'll let you know......
Mark Heller "Well - I oughta....." -Jackie Gleason
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Joined: Jan 2005
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"Hardfacing" is both effective, and a time-proved technique. The only real 'downside' is that you need to be able to grind a new point- without grinding through the new metal.
I believe that three things have made 'hardfacing' a thing of the past: the availability of cobalt steel (and coatings like TiN), the availability of carbide bits, and the affordability of bits.
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Joined: Jul 2002
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Has anyone figured the cost of the actual hard-facing rods?. You cannot use standard rutile rods to do this job. Also, to build a surface up on a drill bit would take real skill.
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Joined: May 2003
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Take TRUE hardfacing out of the equation, I'm looking to put some matierial back on there so they don't have to be tossed out. Nothing left to sharpen on most of them. Even mild wire would be harder than the steel that's not there anymore- really... And maybe harder that the steel that is still there? I just have so many bits that are past sharpening, and at 25-30 bucks each - thats money... And might take a few minutes each....
Mark Heller "Well - I oughta....." -Jackie Gleason
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Joined: May 2005
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I had a short and stressful production job over 20 years ago TIG welding an assortment of cutting tools which were reground. Obviously there was no issue with hardness or temper, but I believe they had ovens. Anyway, like all metalurgy, there's a method to their madness.
Dave
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Joined: Sep 2006
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e57 in all respect, what you are calling tempering ain't. The steel would have to be annealed first, which is heating the metal to about 1500 degrees, then slowly cooling in ashes or vermiculite; then, it is heated back to what is called critical temp. again, only a little higher this time, about 50 degrees above where the steel looses magnetic attraction, then it is quenched in a suitable medium such as oil, brine or water; then it must be tempered; that is, heated to about 400-450 deg. and allowed to slowly cool. Then you can file a new cutting edge. The problem is complicated by the 10,000 degree welding temp. causes there to be places on the new metal where it's so hard that a carbide milling cutter will shatter, so the idea of just welding a small amount of new steel on the end of a tool steel auger is, in reality, quite a difficult process. I wish I had a plan because I also have a mess of bits that are too worn to re sharpen again.
[This message has been edited by Almost Fried (edited 10-21-2006).]
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Joined: Jul 2002
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There are some cyro places that are kinda cheap. The prices were low enough at some I checked out to make me wonder if the bit gets any treatment at all, or is the treatment being applied to the payee instead? I got interested in this stuff a few years back after discussions with a motorhead neighbor who sends brake rotors and all sorts of stuff to the mainland to get treated. I looked into starting up a treatment shop right here, cause there isn't one in this state, but found the startup costs to be too high for our low population to make it work.
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