Small ring Mauser lug lapper

This is for a small ring Mauser with a .98" 12tpi thread. It will also work with Gewehr 88s.

The plunger is a welding tip from a Bernard q-gun. A 5/16" bolt could also be modified to work. The plunger can be 3d printed.
https://www.amazon.com/10-pk-Welding-Contact-Bernard-Centerfire/dp/B088FPFQ4M/ref=sr_1_1?keywords=bernard+centerfire+tip&qid=1636247065&qsid=146-3924171-3245601&sr=8-1&sres=B088FPFQ4M%2CB004HF66DE%2CB07H1YXCJG%2CB01M11WHON%2CB07H22CKQK%2CB00JDSTW0Y%2CB07D9BQY4K%2CB07F1DQR5Y%2CB001AIULYG%2CB002ORB2G8%2CB07FY5KCFK%2CB07THWMZ7R%2CB07F1KG6RS%2CB07F1CMT43%2CB07BLQFQNN%2CB005FTPZSS%2CB003GM9Q1S%2CB004HM5ZQ6%2CB07SC5QN64%2CB07THZC1PM

For the bolt I used a bolt from a vise grip. The tip of the bolt is reduced and the spring slides on. The knurling on the bolt also makes it easier to use. A standard 7/16" bolt could also be used. The bolt can be 3d printed.
https://www.amazon.com/Irwin-Tools-2071910-IRWIN-ITEM/dp/B001NNGJ9E/ref=sr_1_5?keywords=vise+grip+screw+replacement