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OLD MAN
03-24-2010, 01:38 AM
I have severl large bits I am unable to use because of the large taper.I would like to turn them down to be more suable. If I heated the taper to a cherry read and allowed it overnight to cool would I be able to machine it.:)

Cavalry
03-24-2010, 03:56 AM
Yes, but you may have issues with it warping with an uneven heat. If you have a self cleaning oven these often will get hot enough to anneal. (just make sure there is no oil and momma-bear is gone). If you are limited to torch heating, I would chuck it in a drill press or something and heat while its turning then bury in kitty litter. Annealing is best when you can heat, hold, and then cool slowly.

How are you going to harden afterwards?

digger doug
03-24-2010, 07:06 AM
I'm going out on a limb here, but assuming you mean large drill bits,
and you want to turn down the morse tapered end.

You ussually don't need to do anything, just turn them.

I have done a couple of them, the ends are not hard.

You will definitely find where the hardening starts though,
when you turn them, ussually up into the flutes a little.

OLD MAN
03-24-2010, 07:33 AM
Did you put tin around the bit to protect it from the chuck?:)

digger doug
03-24-2010, 07:43 AM
We always used thick pieces of copper, about 1/16" thick,
was wrapped around each jaw (to hold it in place).

I think you could flatten some 1/2" copper tubing.

Randyjaco
03-24-2010, 08:05 PM
The shank of the bit is seldom hard. I turn them down on the lathe frequently. HSS tools will work in most case, but Carbide will just about guarantee success.

Randy

Silverback
03-24-2010, 10:05 PM
Yes, but you may have issues with it warping with an uneven heat. If you have a self cleaning oven these often will get hot enough to anneal. (just make sure there is no oil and momma-bear is gone). If you are limited to torch heating, I would chuck it in a drill press or something and heat while its turning then bury in kitty litter. Annealing is best when you can heat, hold, and then cool slowly.

now why the heck did I repeat the part about annealing in a self cleaning oven out loud in front of my wife. I'm already in trouble and I haven't even done it yet.

How are you going to harden afterwards?

that's what I was wondering

OLD MAN
03-25-2010, 12:12 AM
Problem solved, I ordered a new drill bit from Victor this morning. The windmill boys will pay half and the bit will be mine.:)

clive
05-05-2010, 03:46 AM
As already stated you can turn the shanks easily. We used to make long drills by turning down a step and drilling a hole in some shafting a bit smaller than the drill for clearance. then silver solder the two and you have a drill whatever length you like, we used to use them for drilling out the flail element on a 8ft. rotary mower, bushing up to tne next size when it was worn. Two drills, one 4ft then swap to the 8ft. one, piece of cake.
Clive

Ed ke6bnl
05-05-2010, 06:51 AM
The shank of the bit is seldom hard. I turn them down on the lathe frequently. HSS tools will work in most case, but Carbide will just about guarantee success.

Randy


I also have turned them down with no problem. Wrap the part with aluminum can for cutting edge protection Ed