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Thread: A tapered drill bit.
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31st Aug 2020, 11:50 PM #1Senior Member
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A tapered drill bit.
Hi everyone, I have been tasked to make a quantity of file and rasp handles for a guy with a mild hand disability to a design that suits him. Fairly normal except that it takes me so long to drill the tapered holes in four stages for the tangs. I was wondering if anyone could suggest how to make a tapered drill bit to do this in one go, or is it not feasible?
As usual, all help appreciated.
Thanks,
Rgds,
Crocy.
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1st Sep 2020, 12:03 AM #2Member: Blue and white apron brigade
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You can buy these - look on ebay
Some old brace bits come in tapered form
Also look at how a step drill is made.
Dewalt sell a spiral step drill that clears better than the regular step drills. Not cheap though
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1st Sep 2020, 12:16 AM #3Most Valued Member
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Hi Crocy, I presume that the handles will be made from wood??
The way that I'd do the drilling part is to first drill a pilot hole then use the tapered drill to bring it to size. As you haven't mentioned the size of the bit, I again presume that it would be about 6 mm diameter, to make it a tapered bit. I'd put it in a drill press or a lathe, if one is available, and run a grinding wheel or a flap disc on the bit to create the taper.
Once you have made the taper, you need to be careful about the next part, and that is to grind away a bit of the land behind the cutting edge, so that it has clearance to prevent it binding.
I know it's a bit agricultural, but it's the only way that I can think of to make a tapered drill bit, without a tool and cutter grinder or fancy equipment.
The other alternative would be to make a piece of steel the same shape as the tang on the files, heat it red hot and push it into the wood, creating it's own taper.
HTH
KrynTo grow old is mandatory, growing up is optional.
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1st Sep 2020, 12:58 AM #4Most Valued Member
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You could also make a D bit style form tool and plunge that in. They have some odd relief dut its doable by hand.
Sent from my SM-G973F using Tapatalk
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1st Sep 2020, 02:35 AM #5Senior Member
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There are tapered wood screw bits up to 3/8" in diameter in long and short taper. Maybe they can be had in Australia. Check with traditional wood boat builders. The Jamestown regular bit info has a table with the dimensions of the various bits. You could take an old three cornered saw file and grind off the teeth, sharpen the edges to make a hand reamer.
https://woodshopbits.com/products/ta...=8861887725631
https://www.jamestowndistributors.co...uct.do?pid=473
https://www.jamestowndistributors.co...uct.do?pid=474
Pete
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1st Sep 2020, 06:41 AM #6
Hi Crocy, Kryn, Guys,
Kryn has it right ! In the old days the normal way to fit file handles was to drill a hole about the size of the small end of the file tang, and then heat the file tang up to red hot and push the red hot tang into the wood so that it burnt a hole the same shape as the tang. Don't twist it just push the handle onto the red hot tang. You might have to do this a couple of times.
Hold the file in a vise and heat the tang with a blow lamp. When you have got the handle on as far as you want. let it cool, dip the file tang in a drop of oil and fit the handle giving the end a tap with a mallet. At this point you can easily remove and refit the handle as you wish.
Old timers used to just bang the handle with the file in it on the bench to fasten it, then when changing a file, slide the file over the back of the vise to knock the handle off.Best Regards:
Baron J.
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1st Sep 2020, 08:00 AM #7Philomath in training
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I've always used the 'red hot file' method myself. It works.
Michael
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1st Sep 2020, 08:39 AM #8Most Valued Member
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Small diameter tapered reamer?
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1st Sep 2020, 09:31 AM #9Mechanical Butcher
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1st Sep 2020, 09:35 AM #10Most Valued Member
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BaronJ already did. Post #6.
Chris
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1st Sep 2020, 09:59 AM #11Most Valued Member
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red hot for me too..... but after a pilot hole of course.
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1st Sep 2020, 10:25 AM #12
I always pilot drill and step drill one size under so they stay on. I some times use a tapered reamer which can be used in a drill
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1st Sep 2020, 05:57 PM #13
Hi Guys,
A bit of trivia...
I have it on good authority that the Chanters for Bagpipes, which have a tapered hole through them, were normally drilled using a three cornered Bayonet !Best Regards:
Baron J.
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1st Sep 2020, 08:00 PM #14Senior Member
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Thanks for all the replies, I tried Kryns suggestion. I looked at how a spade bit is made and grabbed a bit of 12mm 4140, milled it to 4mm , then milled the angle. Ground the edge relief on the bench grinder and then used an almost worn out 100mm cutoff disc in the angle grinder to provide some cutting edges.
First try it really struggled, so I drilled a 4mm pilot hole and it was ok. A bit agricultural, but I got my tapered holes to match the tangs.
As usual on this forum, lots of nice people willing to help.
Thanks,
Rgds,
Crocy.
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1st Sep 2020, 10:02 PM #15Most Valued Member
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Thanks for letting us know how you got on with the job.
KrynTo grow old is mandatory, growing up is optional.
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