AR 15 Front Pivot Pin Installation Tool x2

thingiverse

I figured installing a lightweight spring wouldn't require metal reinforcement, so I plan to make a pair using PLA soon. There are numerous videos online explaining how to use these tools, but the concise version is this: insert one through the pin retaining flanges, align it so that the hole allows you to put the spring and detent in place. Next, use the smaller end to drive the detent far enough for the assembly to rotate. Align the pivot pin and drive it in, allowing the tool to slide out simultaneously. This will enable the detent to catch on the hidden flat part of the pivot pin, and voila, you're done. Keep in mind that the detent will eventually wear down the tools, but if you're doing a dozen or fewer assemblies, consider using high-quality steel ones instead. This is more suited for hobbyists like myself who only need to assemble a few tools.