5/16 x 18 tpi x 3/4 long is what the AMK site shows.

https://www.amkproducts.com/bulk-fasteners-products/?Product_ID=11605

If they thread in without the tool in place it could be the slots in the tool are not 100% on center exactly. If that is the case the slots in the tool need opened up a small amount.

Last edited by Neil; 04/16/24 09:46 PM.