WTF-9: Bolt Welding Jigs After you have prepared you bolt stock for welding you can use the welding jigs to make things a bit easier for alignment. Slide the front welding jig over the forward bolt section until it bumps the square shoulder where the upper dowel becomes larer. next insert the lower dowel into the jig (as seen in pictures). Use the slot in the welding jig to ensure firing pin alignment As seen in pictures). both dowels should fit tight in the jig. The rear jig in tandom with the front jig keeps the upper and lower dowel parallel. Abetter option is to use only the front jig and clamp the rear portion of the two dowels using vise clamps and some flat steel (as seen in pictures). I highly recommend the 2nd option because it prevents the dowels from rolling due to welds slightly shrinking.