Is a half nut a different thing in the States?. i meant one of these, looked like there was room for one on your photo and made for the job.
Let me get out of the way now and you can carry on the way you were, you seem to be managing fine without me.
No worries LOL
I see, when you say "1/2 nut", it means "thin/low profile/jamb" nut". Gotcha, that might have fit back there, but the OD would make it tight, and be a pain to hold in place while threading the idler pulley/bolt through the plate, and then into it. But, could be a solution
Regarding "half nut", me and John were referring to this LOL
I ordered a M12x1.75 allen head cap screws from McMaster-Carr yesterday, should be here today
I couldn't remember the length I needed, so I ordered them 100mm long, thank God for the Dremel!!!!!!!!!!!!