Found this in a box of assorted scrap, but curiosity got the better of me! It LOOKS like someone fashioned a slot screwdriver bit out of an old 5/16" drill bit, but the grind looks like it was done by a machine, very neat and even. What REALLY caught my attention was the 5/16" SQUARE hole dead center in the shaft, and about 5/16" deep! The whole thing is 3 1/16" long. Any ideas? There is a diamond on the shank with "WILT" in it, and a "/16", apparently the "5" above it was worn off.

 

Edited February 2, 20242 yr by HARO50

Probably out of some sort of heavy duty cnc milling machine. 

May have been an attempt, successful or otherwise, to make a square drive shaft.  A flexible shaft for rotary tools use a cable with square ends.  They happen to be the same cable as the speedometer cables used to be.  About a 1/8" square hole.  That is my wild arse guess  anyhow.    

Interesting tool. Haven't got a clue what it is, but if I ever need to borrow one good to know you have it.

12 hours ago, HARO50 said:

What REALLY caught my attention was the 5/16" SQUARE hole

Sorry, I had a senior's moment there. the hole is just under 1/8" square.

19 minutes ago, HARO50 said:

Sorry, I had a senior's moment there. the hole is just under 1/8" square.

 

Falls right in line with the flex shaft theory.  Pretty much all of them use that size.  Do you have one to try?

Fine example of redneck engineering.  Looks like a pneumatic hammer bit...kind of sorta. 

 

.40 

4 hours ago, HandyDan said:

Do you have one to try?

Unfortunately, no.

 

3 hours ago, forty_caliber said:

Fine example of redneck engineering.  Looks like a pneumatic hammer bit...kind of sorta. 

 

.40 

What gets me, the square hole had to be there on the original tool. I looked up "WILT", but that was pretty much a dead end.

4 minutes ago, HARO50 said:

Unfortunately, no.

 

What gets me, the square hole had to be there on the original tool. I looked up "WILT", but that was pretty much a dead end.

I think the Wilt is for Wilton.  The square hole is likely some kind of centering alignment on what used to be a twist drill.  I also noticed that the flutes seem a bit wider than normal... carry away more chips maybe?

27 minutes ago, HARO50 said:

Unfortunately, no.

 

What gets me, the square hole had to be there on the original tool. I looked up "WILT", but that was pretty much a dead end.

 

Tool steel can be annealed, reworked and hardened again.  Also there are grind marks on it that most likely wouldn't be on a new tool.