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Post by Tim Bayliss on Oct 25, 2005 14:08:04 GMT
Folks,
I have a drunken threaded hole in one of my Dickson type spare QC tool holders. The other day I decided to drill it out and re-tap it. The standard HSS drill made a horrible noise and didn't touch it (nor did a test file) - obviously it's been hardened, and quite well I'd say.
I don't want to try to anneal it due to stresses, etc., and anyway it may be some of the new stuff that can't be annealed.
I've never used solid carbide drills, would they do it? Or has anybody out there other ideas.
Thanks in anticipation,
Tim
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Uzzy
Hi-poster
Posts: 153
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Post by Uzzy on Oct 25, 2005 15:29:58 GMT
Don't know if this will be of anyuse but I remember years back at the shows Drills that would drill anything Files included.
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lancelot
Part of the e-furniture
Posts: 471
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Post by lancelot on Oct 25, 2005 16:02:18 GMT
Hello Jim,
judging from what you say about hardness of the material, cobalt or even a pure tungsten drill [would cost a bomb] might do the trick, but then ,depending on the size of hole you are drilling out,you need to go at least twice as big to enable a plug to be fitted and drilled and tapped back to original size,and end up being vertical!!.
If I had the option,I would seek out a local technical college or engineering company, that would have a SPARK EROSION MACHINE...in short , this machine will bore out [electronically] any calculated hole size,in the hardest of materials, to any given depth, vertical or otherwise, enabling a plug to be freeze fitted, drilled and tapped back to original. I think it might be a good project for an engineering student at college.
All the best of luck,
John.
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Post by steammadman on Oct 25, 2005 17:26:29 GMT
hello tim,
it's just as cheap to scrap it and either buy a new one,
or do as i did a few years ago make some.
i made mine out of steel ( en 26?) , i think or something like that,
a bit harder than mild steel any how, mine have lasted me about 5 years or so ,
and still going strong!!.
like a typical yorkshire man , niver spend tha money on owt tha can mek!!!.
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JohnP
Hi-poster
Posts: 186
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Post by JohnP on Oct 25, 2005 19:28:08 GMT
I think the drills are called "Frhei" or maybe an anagram of that. I ordered some for work last year when we were drilling some inconel. The drills were about £37 for a set and looked very much like ordinary masonry drills BUT they did work very well. They work up to red heat so keep your mouth closed when using them!
The instructions did say that they prefer to drill in one pass rather than progressive opening of the hole.
Cheers,
JohnP
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Post by Tim Bayliss on Oct 26, 2005 8:01:06 GMT
Thanks for the info lads,
I think Steammadman makes a valid point about costs. I believe I can get a replacement unit for about 20 quid which kind of puts things into perspective.
I've seen the drills JohnP and Uzzy mentioned, not used them myself but worked with a guy who had & he said they do what they're supposed to alright.
There aren't any proper engineering colleges in this vacinity - Ireland is training all the young uns for IT, bank and legal jobs! so not much chance there.
I may put it on long-finger for a while, it's not going anywhere!
Regards,
Tim
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Post by steammadman on Oct 27, 2005 9:14:11 GMT
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Post by rtownsend on Oct 28, 2005 11:49:14 GMT
Tim
The drills they use for drilling files are stellite drills. You run them as fast as the drilling machine will go and they actually melt a hole through the material they are drilling. The drawback is that the "skin" of the drilled hole is exceptionally hard and a tap won't even look at it. So I agree with steammadman and you should cut your losses and get a new one
Regards
Reg
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