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Big Twist Drills

Ultradog MN

Cast Iron
Joined
Jun 14, 2020
I got these at an auction.
Cheap!
1 3/16" #4 MT
1 1/2" straight shank
1 11/16" straight shank.
All US made.
What to do with them?
My lathe uses #3 MT
Should I sell them on fleabay then buy something I could use or turn #3 Morse tapers on them?
Don't know that I need that big of bits for my lathe either but I could? use them that way.
What say you guys?

20211202_151216.jpg
 
The larger size Jacobs super chucks go to 1". Turn a 1" shank on them if you think you must use them in your lathe.

3MT is not much of a driving force for those drills though. You'll twist 3MT right off if you have the power to use those drills.
 
Just turn the shanks down to whatever your tailstock chuck can handle. Your drilling won't be aggressive with a large diameter drill and a small shank due to limited grip, but I've had no trouble using a 1 3/16 drill with a 1/2" shank. Just don't hurry.

Its rare for a drill shank to be hard. If you have any issues it will be with the MT4.
 
Just turn the shanks down to whatever your tailstock chuck can handle. Your drilling won't be aggressive with a large diameter drill and a small shank due to limited grip, but I've had no trouble using a 1 3/16 drill with a 1/2" shank. Just don't hurry.

Its rare for a drill shank to be hard. If you have any issues it will be with the MT4.

Mill 3 flats in the shank...so you can see if the tailstock is really attached well lol
 
The larger size Jacobs super chucks go to 1". Turn a 1" shank on them if you think you must use them in your lathe.

3MT is not much of a driving force for those drills though. You'll twist 3MT right off if you have the power to use those drills.

Lathe is 5 HP.
Maybe not put a tang on them?

Just turn the shanks down to whatever your tailstock chuck can handle.

Its rare for a drill shank to be hard. If you have any issues it will be with the MT4.

I tested the shanks with a file. They are not hard and would cut ok.
 
On oversize drills do not use the tang to drive. Put a lathe dog on the drill and brace it against a boring bar in the tool post.
 








 
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