My ML7 came wit a rotating 4 tool holder designed to take a 5/16 sq hss tool piece, I decided I wanted to revert to the simple tool clamp which can take 1/2" shank and so removed the 4 pce block. I found the original handle didnt have a thru thread so have to find a nut (or pay ca £5 for a Myford long nut. Well I was really puzzled when I couldnt get the std nut to fit, I even dug out a 7/16 die nut to chase the thread – which started chewing thread – funny had the correct od?

so stop – think????

light bulb moment, I checked my thread table and found it was a 7/12 UNF 20tpi vs 18 tpi for bsf – wasted an hour on this

anyone else come across this anomally – was it part of the 4 pce tool block attachment? thats my guess

Indeed I was fooled by this for a while. I have taken to sourcing a car wheel nut which doubles as a long thread nut. 7/16 unf is a common size for small cars. I was also caught out by this unf/bsf switch when restoring an old ransomes mower, I didnt expect a switch for some of the chassis parts

mixing different thread tables in your workshop is a nightmare. I have taken to spraying trays with different colours so perhaps they dont get confused.

btw how do i get to post pictures on here? i cant see how to create an album?