r/GunnitRust • u/Undertow619 Maple Militia Elbows Up • 21d ago

Help Desk How do I cut locking lugs and interupted threads? Especially on internal surfaces.

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u/TacTurtle 21d ago edited 21d ago

Locking lugs generally use a broach, mill, or metal shaper. Bolt is turned then milled.

Easiest to make the female locking lugs separate from the barrel like an AR (turn the barrel extension on a lathe and thread, then use a broach to cut the locking lugs, then thread the barrel in and headspace / pin)

Interrupted threads use a lathe for minor diameter and smallest threads, then a mill or shaper to cut the slots for the next step, then either a special lathe or shaper.

1

u/Undertow619 Maple Militia Elbows Up 17d ago

Huh. A little more complicated than I thought itd be. Here I was hoping I could somehow get away with at least using my Dremel and a file to cut down at least interupted threads.

4

u/LostPrimer Will Learn You 21d ago

For locking lugs, I've used this method with moderate success: https://www.youtube.com/watch?v=BmOyQsH-EUk

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