Strap Screw Inserts

[Chris Ghent]

Could I add a small note of caution... You measured 2.2 which is the major diameter of 8BA but 8 BA is very tiny and it is hard to imagine anyone using it for this. A possible explanation is that the thread was worm from years of use and abuse, and that it is actually 7BA which has a diameter of 2.5mm.

 

The easiest way to check if you do not have micrometers etc would be to find a screws of known BA size and try them in the hole of the insert.

 

A BA thumbscrew is about 10 minutes work on a lathe. If you get stuck, send the insert to Richard Evans in Australia. He makes all kinds of replacement parts, including ones for which there are no dies.

 

Chris

[d.elliott]

I would suggest that you use the advice given to establish which BA (?)thread it is.

 

Then drill through the centre of the old thumb screw head (some of the thumbscrews' screwed portions were sweated or brazed into the head) tap out the hole in the head and solder/ loctite/ capture a new bit of screw thread into the screw head, polishing the top surface to suit. Sounds messy but it should be straight forward

 

Dave