Thompson firing pin retainer jig

thingiverse

This is a jig for drilling a 1/8" hole for a firing pin retainer in a Thompson bolt. For my semi build I chose to use an ar firing pin. The head needs to be turned down to under 1/4" to fit the bore of the bolt. The tip will need to be turned down to fit the bolt. Since the firing pin hole on my bolt was welded, I chose to use an ar firing pin liner from Tec Tactical. That required a 1/4" hole all the way through the bolt. The rear of the existing hole is already 1/4" so the drill bit is guided while drilling from the rear. All that is needed is an extended drill bit. I just welded a regular bit onto a piece of 1/4" round bar. The bolt will probably need to be annealed for drilling. For only drilling the retaining hole it only needs to be spot annealed. To use a steel guide is also needed. I designed the jig for a 1/4-20 bolt. The Fusion 360 file is included so it can be adapted to other guides. This is the ar firing pin liner. http://tectactical.com/UPFL.htm