Easy as 1-2-3?

I have a pair of Brown & Sharpe 1-2-3 blocks The part number is 599-750-50

They have have some holes that are threaded 5/16-18 and others that are thru holes large enough for a 5/16 bolt to go thru. In other words you can use a 5/16-18 bolt to bolt them together or to bold to a T-Nut with 5/15-18 threads. Additionally the thru holes are also counter-bored to allow a socket cap bolt to recess below the surface when doing any of the a fore mentioned bolting. It took me a long time to find these and I think they address the original posters issue (and mine).

599-750-50.png

599-750-50.png
 
One way i thought of was to use thin-wall Keenserts. One that installs in a 3/8-16 thread will have 1/4" internal threads.

Dennis
 
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