80% lower help

[S. Wong]

I drilled out the selector hole on a pair of 80% lowers using a drill press & reamer.
when trying the selector in the hole after putting in the trigger & hammer assembly, one drops the selector in perfectly, but the other, the two sides are 1/64th of an inch off from eachother.

How can I fix this?
Can I just use the right size bit and drill it out a bit more?

Also, the selector retention pin doesn't go deep enough to positively lock the selector in safe or fire for either lower.
How should I drill that one out so that it fits better?

All the other pins fit snugly

[nate76239]

I wonder if the jig might be slightly out of spec or something. The hole for the selector is 3/8 inch. I had a lower where the selector went ok through the first hole but was binding up on the second, I used a 3/8 end mill bit to smooth it out, I think my regular 3/8 drill bit was wearing out. As far as the selector detent not going in deep enough to lock it maybe try stretching the spring or put something behind the detent so it goes further. I definitely think either the lower or jig was out of spec

[Nathan Krynn]

Proper order is as follows.

1) trigger assembly
2) selector assembly
3) selector to fire
4) hammer assembly

If you do the hammer before the selector it probably will bind.

[Nathan Krynn]

Wait I failed at reading comprehension.

I bet you drilled from both sides and now it doesn't line up or milled it out first.

You should peck drill from one side through solid material to prevent this mis alignment.

A lot of people I have heard from drill larger and then put in a bushing.

[Nathan Krynn]

On the selector detent the hole should be stepped. Do not drill out this step all the way. Make sure you have the right spring and detent. Then measure the step.

Also make sure your selector hole is centered to the detent hole.

Who's 80%'s and jigs were these if I may ask?

[S. Wong]

The irony is that I used the same press, jig, and bit for both lowers.
Drilled through in one pass, then reamed.

the 80% were picked up from a guy in San Jose, affiliated w/ Dr. Death.

The selector detent is stepped, but I haven't measured to see if the hole is simply not drilled through or if the step is too shallow.
I was testing this by using the PSA Premium lower kit detent and just a screwdriver to push the detent up for testing, before I added the spring.
Still won't actuate positively.

[S. Wong]

BTW, the main cavity was milled out before the holes were drilled in

Also, I was following the assembly instructions from AR15, which said to do trigger, then hammer, then selector.

If I have to pull everything out and start over, I will

[bohoki]

just run the 3/8 bit through both sides and let it run for a bit

you can just drill the selector detent out again its probably full of burrs

[michiganboy]

after milling usually the detent hole gets excess metal in it, just check and see if you can push the detent all the way in with something. Then put in spring, and try it out.

[edgerly779]

I am in sfv and have a tm jig if you want to stop by and we can check your lowers. I have done several and they work perfect. I mill pocket first then drill from one side only and do hammer hole then trigger hole then safety/disconnector then debur with fine hand held 45 degree chamfer tool. Then use small emeryboard to smooth inside of fcg pocket.

[Nathan Krynn]

I wouldn't use a screw driver to test it. Put the spring in the grip and push the grip on. Too many variables with a screwdriver and you can test it with the actual grip so go for it.

There might be burs or metal in the hole like people said too.

I feel your pain though and am sorry you are having issues.

[S. Wong]

edgerly779, I'm in San Ramon, but tomorrow my wife and I are going to the Littlefield tank auction in portola valley to check it out.
She's told me we cant afford a toy, nor do we have a garage to store it in.

I'll send you a PM and see what we can schedule

[RookieShooter]

I usually drill all the holes first before milling the pocket to prevent the drill bit from straying off course.

[MustangSteveGT]

In my ghetto opinion. Pack with JB weld, let it cure, then redrill from the other side so its aligned. When the lowe is painted aint nobody going to know.

[S. Wong]

I used a 3/8" hex to work back and forth in the hole, and its tight, but the selector went in.

Popped that out, and worked a drill bit using my fingers to clean out the selector detent.

now both work perfectly.

Thanks,
-Steven