I've got a couple scopes and plug-ins that are missing the knurled thumb nuts from some of their ground binding posts, and I've been searching for replacements for a few months.
The binding post is a 1/4-28 thread, and the nuts are about 3/8 inch outer diameter, and 3/8 inch tall (there are shorter nuts for some TM500 and 5000-series plug-ins that are only 1/4 inch tall, but those are not the ones I'm interested in).
I've found one reasonable replacement (not a good cosmetic match, but very close to the same size, and still looks pretty good on the instrument). It's an "internal wrenching allen nut, 1/4-28" and there are a few for sale on eBay (I am not affiliated with the seller), but I'm sure you can probably find these from regular distributors (e.g. Fastnell) with the proper specs in hand.
I'm also looking at some 1/4-28 threaded brass inserts as possible replacements, but those have not arrived yet (taking, as they say, a slow boat from China). I will report on their suitability when they arrive.
-- Jeff Dutky
