Irwin Adapter Shank Wood Bit

[Pexto]

I happened to see this little curiosity in a Craftsman wall cabinet (https://www.garagejournal.com/forum/threads/craftsman-wall-cabinet.390573/post-11132680). It probably dates from the mid-late 1950s. NOS, never used, still with protective coating and the original label.

I've seen a lot of brace bits cut off for use in a power drill, but never realized that Irwin made bits that were specifically made so that the square taper could be cut off, leaving a hexagonal shank.

The label reads:

Fits both hand brace and electric drill
*PATENTED
New Irwin Adapter Shank Wood Bit

a. Use bit in hand brace as
it comes.

b. Cut off at point (b) for use
in electric drill. Leave small
section of round shank ex-
tend beyond "hex flats." Point
runs true. No wobble, no run-
out. 6-flatted section chucks
perfectly in hand brace, too.

c. View of Adapter Shank
as seen through patented
6-flatted section.

Not recommended for small 1/4" drills.

 

[WisJim]

I bought a similar one around 1980 to drill bolt holes in 6x6s for a pole barn I was building. Still have it.

 

[RTM]

I think I have one kicking around somewhere too but definitely not NOS.

 

[Pexto]

I bought a similar one around 1980 to drill bolt holes in 6x6s for a pole barn I was building. Still have it.

Assuming you used it with a power drill, how well did it work?

 

[Pexto]

I think I have one kicking around somewhere too but definitely not NOS.

Do you happen to know if the cutting edge geometry is the same as a normal Irwin solid stem brace bit? I'm curious to know whether they modified the geometry for use with a drill, or whether it's just a normal bit with a bit of hex shank added.

I don't own that auger bit - just had an opportunity to take pics. Otherwise I'd compare side-by-side.

 

[RTM]

Do you happen to know if the cutting edge geometry is the same as a normal Irwin solid stem brace bit? I'm curious to know whether they modified the geometry for use with a drill, or whether it's just a normal bit with a bit of hex shank added.

Will take some digging to find it, my loose brace bits are buried a bit. At the time I got it, I was not savvy enough to pay attention to the cutting edge.

Remember , the drills of the day ran much slower than they do mow.

 

[Pexto]

Remember , the drills of the day ran much slower than they do mow.

Yes, and drill speed might be why the instructions warn against using 1/4" drills, which typically ran faster than 3/8".

 

[WisJim]

I'm not sure exactly where mine is, but I'll look for it, maybe later today. I didn't pay attention to the cutting edge, or remember if I did. I used it in my old Craftsman 1/2" drill at the top of a 20 foot ladder and it worked well.