Captured spring for rear takedown pin

kcult

kcult

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I just did this to one of my Anderson lowers. Easy peasy.

No drilling. Just stick your tongue out of the right side of your mouth if you're right handed, and vice versa. Tap the hole.

I used the starter tap to, uh, start it. Then, I used the plug tap to get the length of threads I wanted. I didn't bother with the bottom tap since this isn't a blind hole.

I used a M3x8 set screw. I cut off a section of the spring to account for the screw, then assembled.

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Sent from my SM-G920V using Tapatalk
 
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Good informative write up, thanks.
 
Just did two more stripped lowers. As time permits, I'll be doing this to my assembled lowers.

I'll post a couple more pics after my phone charges a bit.
 
This should be standard on all lowers!
I have a Spikes Grock lower that came with it.
And just built a Aero M4E1 that is threaded as well (although had to pick up the 4/40 plug screw).
It really helps with the three hand dance of capturing everything with the castle nut/tube installation.
 
I've noticed this feature on a couple of 9mm lowers. My NewFrontierArmory lower also had a set screw for the bolt catch instead of a roll pin. Makes replacement a lot easier.
 
Did you find a place to buy those taps as a set?
 
JohnnyTyler said:
I've noticed this feature on a couple of 9mm lowers. My NewFrontierArmory lower also had a set screw for the bolt catch instead of a roll pin. Makes replacement a lot easier.
Click to expand...

This is the one that makes a difference for me when assembling. No pressing in a roll pin and all that
 
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Grabbed a tap and set screws earlier this week. Decided to try a couple of my lowers this evening. First two I worked on were both Aero, and already threaded. :D

3rd one wasn’t, and didn’t take but a minute to get a couple threads. 4-40 tap and 1/8” long set screws.
 
BigWaylon said:
Grabbed a tap and set screws earlier this week. Decided to try a couple of my lowers this evening. First two I worked on were both Aero, and already threaded. :D

3rd one wasn’t, and didn’t take but a minute to get a couple threads. 4-40 tap and 1/8” long set screws.
Click to expand...

I need to start working on mine. Thanks for the reminder.
 
Got the rest of them done today, except for the one in my wife’s vehicle.

All the Aero lowers were threaded. The only other one I found threaded was a Spike’s (but not any of my other Spike’s). I was a little surprised the Seekins and/or Mega weren’t threaded. PSA is threading some of theirs, but none of mine had it. Neither did DPMS, Bushmaster, JD Machine, or Zombie Defense.

Now what to do with ~90 set screws. :D

Seriously, though...anybody local to me is welcome to stop by and we’ll knock yours out real quick.
 
I would add that you should heat the cut end of the spring to close it up into the last coil.

Heat up the head of a 16 penny nail red hot and touch the end of the spring to it - it will draw right up - finish by grinding the end flat if necessary.
 
I’ve been doing this for years, super easy, cheap, and functional.
 
One of my aero lowers was tapped, but I guess the previous owner didn't want to use a captured spring. I noticed the spring was damaged, so I snipped it shorter, but the tapped hole was a standard thread. I was able to run a M3 tap in it and use a M3 set screw. I did that because I'm covered up in those.
 
Three more done that I picked up today. Easy peasy.
 
I'll probably do my space rider lowers when they come in next week.

And I think I did one of my pistol lowers a couple of weeks ago when I installed the law tactical folding thingy.

Easy peasy.
 
Putting together an Aero lower later today. Any hints on where to get 4-40 set screws without having to buy a 1000 of them?
 
You have a Grainger nearby? They have 100ct package on clearance for $2.79. I get free next day shipping on most stuff due to work account, and that’s where I got my last ones. Looks like shipping is $11 or so. :eek:

ETA: looks like you can choose store pickup and avoid the shipping if you’re nearby

Item number: 5XCT7
 
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BigWaylon said:
You have a Grainger nearby? They have 100ct package on clearance for $2.79. I get free next day shipping on most stuff due to work account, and that’s where I got my last ones. Looks like shipping is $11 or so. :eek:

ETA: looks like you can choose store pickup and avoid the shipping if you’re nearby

Item number: 5XCT7
Click to expand...

I'm ordering a pack of these through work so I don't have to pay shipping. We buy enough that we get free shipping.
 
Couldn't find any local so I guess I'm building this one like they did in the dark ages. My upper and lower parts arrived yesterday and there's no way I can let it all set there all weekend without putting it together. Guess I'll order some for the next build because we all know there's going to be a next build. Damn I thought 1911s were addictive.
 
JohnnyTyler said:
Couldn't find any local so I guess I'm building this one like they did in the dark ages. My upper and lower parts arrived yesterday and there's no way I can let it all set there all weekend without putting it together. Guess I'll order some for the next build because we all know there's going to be a next build. Damn I thought 1911s were addictive.
Click to expand...

You can always do it later. If I find myself working on one for any other reason, I'll take time to do this mod.
 
I discovered something else that helped me (at least this time).

I find getting the bolt catch roll pin started to be cumbersome, to say the least, especially without a good way to hold the lower. My buddy has my Bev block and he's currently on vacation in FL.

I don't actually know the name of the tool, but I'll call it a semi auto center punch. I put the roll pin in the hole, stuck the center punch in the end of the pin and slowly began depressing the punch. Slowly. Slowly. Click! The punch activates and the roll pin is started.

In the pic, I'm just showing the tool and the pin. During the process, I was holding the pin to keep it from flying across the room.

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After I installed the bolt catch and tapped the pin almost all the way in with my brass rod, I eyed the center punch again. I was able to use it to get the pin flush in the hole without damaging the finish. It took a couple of clicks to do it. No pic of that. You get the idea, I hope.
 
Here’s a little tip so you don’t have to learn it yourself. If you thread the hole at home, and decide to assemble the lower at work...remember to either bring snips or cut the spring at home.

Because the fingernail clippers in your drawer won’t get the job done. :oops:

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Got the PSA lower tapped and assembled for a .410 firearm build, and the QC10 for an AR-45 build was already tapped.
 
This is now a tips thread.

Did you buy a special bolt catch pin punch and still need four hands to get it started? Find some wire with a conductor that is close to the pin diameter. Strip 1/2” of insulation off. Slip it to the half way point over the end of your punch. Put the pin in the other end.

Line it up on the bolt catch boss and whack it in there. Works well for the gas block pins too.
 
BigWaylon said:
Got the rest of them done today, except for the one in my wife’s vehicle.

All the Aero lowers were threaded. The only other one I found threaded was a Spike’s (but not any of my other Spike’s). I was a little surprised the Seekins and/or Mega weren’t threaded. PSA is threading some of theirs, but none of mine had it. Neither did DPMS, Bushmaster, JD Machine, or Zombie Defense.

Now what to do with ~90 set screws. :D

Seriously, though...anybody local to me is welcome to stop by and we’ll knock yours out real quick.
Click to expand...
I need about 20 of them
 
BigWaylon said:
You have a Grainger nearby? They have 100ct package on clearance for $2.79. I get free next day shipping on most stuff due to work account, and that’s where I got my last ones. Looks like shipping is $11 or so. :eek:

ETA: looks like you can choose store pickup and avoid the shipping if you’re nearby

Item number: 5XCT7
Click to expand...
Grainger still has these. The Clearance price has dropped to $1.67 if you want some. Shipping is high (I think it showed almost $11), but you can do store pick-up for free. Or maybe some of you still quality for free shipping like I do.

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Here are the part numbers for the cheapest 4-40 taps if you need one of those:

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I get my set screws at Automotive Fasteners in High Point.

Sent from my SM-G973U using Tapatalk
 
For anyone wanting to do this, I don't have a tap set to give, but I do have two set screws that Aero puts in their LPKs.

If you need/want them, I'm sure I can mail them in a regular envelope inside a folded sheet of paper.

Holla.

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I’ll add to @kcult’s offer.

For no real reason other than the price and I get free shipping, I just ordered 200 screws and 2 taps for ~$10. If anybody wants a screw (or 10) and needs to borrow a tap, shoot me a message. I think the taps will be here tomorrow (I already have at least 50 screws), and the screws on Friday.
 
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