What are these?

[charlesfitton]

From a friend who recently purchased a toolmakers tool chest at an estate sale.

Theses odd steel cylinders have a square hole through their length.

One end has been tapped for about 1/4 the length, and each has the odd screw with a hex hole through it.

Best I can tell it's a dowel for a blind hole, but I can be convinced that it"s something else..

 

[10K Pete]

Boring bar inserts for holding square tool bits in round holes. The screw allows easy adjustment of the bit.
There have been many times I wished I had some....
What size are they?

Pete

 

[charlesfitton]

2 3/4 long

tight 3/4 OD

tight 1/2 Square hole


( he has others...if he hasn't chucked them)

 

[Charles Lamont]

A stud box (for inserting studs)?

 

[charlesfitton]

Boring bar inserts for holding square tool bits in round holes. The screw allows easy adjustment of the bit.
There have been many times I wished I had some....
What size are they?

Pete

I've been dwelling on this , Pete , but I cant picture what would stop the toolbit from pulling out.. Do you have any details about their use?

pics, maybe?

 

[Inflight]

I've been dwelling on this , Pete , but I cant picture what would stop the toolbit from pulling out.. Do you have any details about their use?

pics, maybe?

How about a video? Keith Fenner has a video about making a boring bar using the sleeves.

[ame]https://www.youtube.com/watch?v=P8kmZ-9SjRA[/ame]


Matt

 

[goldstar31]

I've been dwelling on this , Pete , but I cant picture what would stop the toolbit from pulling out.. Do you have any details about their use?

pics, maybe?

Mine is proprietary, and the bit is held with a tapped rod bored lengthways through the rod.

My in line boring bar bit is at an angle of 40 degrees and with a 40tpi thread can give advances and retards in thous.

I sort of raised this point only a few days ago- and was deafened by the -----silence.:wall:

I'm wondering for the future

Norman

 

[10K Pete]

The "circle and square" insert is usually held in with a set screw. Now I can't speak for everyone, but when I use them the fit to the tool bit has been quite close (as your measurements indicated) and the pressure from the set screw in the boring bar deflects the insert to clamp the bit as well. I have seen inserts that were slit (not the threaded end) to significantly improve this clamping.

Hope this makes sense!

Pete

 

[purpleknif]

You put a set screw thru one side. I,ve made lots of boring bars.

 

[10K Pete]

You put a set screw thru one side. I,ve made lots of boring bars.

Yep, I'd forgotten about that one!

Pete