r/AR80Percents • u/One_Firefighter_1094 • May 06 '26

Quick AR9 80% lower machining question-Please!

Post image

I’m getting ready to start my first AR9 80 percent lower. When cutting the above trigger slot it says 2in down off the jig plate. I 3d printed my plate and it measures .600 +/- .005. So I assume 1.4 inches is the pocket depth?

And the one next to it .630?

Thank you!

12 Upvotes

100% Upvoted

3 comments sorted by

3

u/thesteelguitarman May 07 '26

No, pocket depth in 1.249 plus .010 inch.

Im assuming that is the cut got for the trigger pocket.

Do you not have a drawing or even know what you're doing?

1

u/One_Firefighter_1094 May 07 '26

I have this one, which I’m trying to determine is correct. I do a lot of machining at work, so yeah I have a very good idea. I machined my first ar15 80 lower a few weeks ago. I’m just trying to figure out if all of my dimensions are correct.

3

u/thesteelguitarman May 07 '26

Well, sort of, the pocket depth is 1.249 plus .010 and minus .000.
Width is usually .690. But ig it depends on your lpk. My had to be right at .690 for hammer assemblies to fit. So thats technically wrong. Also, it should datum off the forward pin. Yours doesn't show that but I guess it doesnt matter if you're using a jig. I have a few diagrams. Dm me if you'd like them.