View Full Version : Brace (bit brace) Chucks

09-11-2005, 09:13 PM
I have a lot of old,(100 yr) tapered square tang drive bits, and would like to use them without cutting the tang off.

Does anybody know of an adapter made for a big drill motor?

I made a couple of "adapters" from dead braces found in deplorable condition, by removing the chuck from the dead brace.

Problems encountered - -
1. Essentially square thread in chuck, quite worn, even new the chuck sleeve-nut is NOT self centering.

2. The jaws snafu. Found orderable new ones, and find they aint even close to equalizing.

I imagine I could make a new male thread measuring on the unworn part of the old male thread, and making it oversize so i could play the cut and try QC. So I think I can make the sleeve nut turn reasonably true.

Making the jaws seems to be the difficulty.
Which brings to mind a bit of sideways thinking is in order.

I know the bit tangs seem to have three more or less standard sizes.
I might be able to swage a square tapered socket starting from a tapered hole to accept a square tang and rig some kind of retainer, that keeps the tang wedged into the socket.

I could do that in three different sizes and put a half inch, or larger shank for a modern chuck on the back of them.

Comments please?

09-11-2005, 10:46 PM
You must really value those bits. The few I picked up at garage sales, I just cut the taper off. They fit in a drill just great then. http://bbs.homeshopmachinist.net//smile.gif

Your idea of a holder should work. I don't have a way to make tapered square holes so I'd just use a weldment of pieces. Turn it down for drill mounting and thread the end for a retaining nut, as you say.