Tapping read detent hole

[gmkoh]

I searched for and got no hits on threads regarding tapping the AR rear detent hole to capture the take down pin detent spring.

My question is should the set screw be greased or lubed to prevent a reaction with the aluminum threads to prevent galling or seizing over time and thuis stripping the threads if the spring ever need to be removed?

What grease should be used? would BP nipple or breechplug grease work? PTFE pipe thread sealant?


In short, the procedure seems to be:
Tap the rear detent hole to a depth of about 1/8th inch (4x40 tap)
(some lowers come pretapped)
Cut about 1/8 in off the spring and insert with detent ball into rear deten hole
Place a 4x40 x 1/8 inch carbon steel allen head set screw (I guess SS would be OK too) over the spring to capture the spring (using a .050 allen wrench)

 

[obnoxious2]

I used the same moly grease that you use for torquing the barrel nut to the upper receiver.

 

[clandestine]

Any Grease should be fine and yes use Grease when you thread steel to aluminum. Avoid anything with Graphite.

 

[gmkoh]

I used the same moly grease that you use for torquing the barrel nut to the upper receiver.

I have never built out an upper receiver- what moly grease would that be?

 

[smdub]

Molybdenum disulphide. Its in CV joint grease and makes it very dark gray. Good for things that reciprocate back and forth very slightly (like CV balls) but don't really spin (like wheel bearings.) But any grease will work on the screw.

 

[gmkoh]

Molybdenum disulphide. Its in CV joint grease and makes it very dark gray. Good for things that reciprocate back and forth very slightly (like CV balls) but don't really spin (like wheel bearings.) But any grease will work on the screw.

Got it!

 

[Americus]

Grease it up and tap it.

Enjoy! Hope you have lots of fun shooting your gun.

 

[Threeband]

Grease it up and tap it.

Enjoy! Hope you have lots of fun shooting your gun.

That's what she said!