Hi All,
Stanley were notorious for having all sorts of odd thread sizes on their tools and accessories!
Most of the small plough planes use 3/16BSW for the thumbscrews but you will often find 5/32 and 7/32 as well, sometimes even 9/32 here and there.
I have just had batches of plough plane clamps made for which I am using 3/16W for the new thumbscrews. It really does not matter except to the ultra purist collectors
i am about to order the LH taps and dies for the adjustable spokeshaves and plane adjuster threads, Tracy Tools being the go to guys!
cheers, Martin