First ever build was the Spectre SI15. Build guide said to melt a brass threaded insert into the lower. That way the pistol grip would be screwed into metal instead of plastic.

Reading the Ubar3 guide, Ivan chose to tap threads into the lower. I trust Ivan’s judgement because he’s been polishing the ubar for 10ish years. In my mind though… the brass threaded insert seems like it’d be stronger since it’s metal on metal. Harder to strip out the threads etc.

Thing is… with Ivan’s method you can use the actual screw that’s meant for the pistol grip. If you use the threaded brass insert. It’s a much smaller flanged screw. I’m not sure what to think.

Would appreciate thoughts/advice.

  • JohnJacobJingle@forum.guncadindex.comOPEnglish
    0·
    25 days ago

    Dangggggg McMaster Carr is bad ass. I’ve made a few purchases from them and never noticed you could do that.

    I’ll probably just go with a m4 or m5 screw/nut so I don’t risk weakening the lower by removing too much material.

    Hypothetically though, If I wanted to use the original ar screw…… From what I’ve gathered, most ar grip screws are 1/4”-28 fine unf. So that means I’d need a 1/4”- 28 fine unf nut?

    I’ll probably use m4/ m5 screw/nut to minimize risk of weakening the fin by removing too much material. Smaller screws make me a tad nervous though.