View Full Version : Pistol Grip Screw Difficult to Screw Back In
I removed a pistol grip from an AR I own and am replacing the grip with an Ergo grip. For the life of me, I can not get the pistol grip screw back in and frankly, I'm afraid I'm stripping out the threading in the receiver, if not in fact basically tapping a whole new threading! I stopped trying to get it in...but what do you recommend? I'm using the same screw that I had to remove to install the new pistol grip.
Suggestions?
Remove the grip and screw and check for thread damage or debris. Run the screw in minus the grip after to check it. Some grips may alter the screw angle and cause your issue. I would place the screw into the grip, fit it onto the lower but do not seat it completely. Start the screw, making sure the alignment is correct turn in 2-3 turns then seat the grip and tighten while making sure the selector detent and spring are seated.
What's the worst case scenario if I have managed to screw up the threading in the aluminum receiver? I'm not saying I have, but...would I be able to return the receiver to the manufacturer and have them retap the threading or have I managed to royally F up the receiver to the point it is no longer usable? (Worst case scenario!).
crosseyedshooter
09-15-20, 14:01
What's the worst case scenario if I have managed to screw up the threading in the aluminum receiver? I'm not saying I have, but...would I be able to return the receiver to the manufacturer and have them retap the threading or have I managed to royally F up the receiver to the point it is no longer usable? (Worst case scenario!).
mark5pt56's advice has helped me in the past. The grip placement sometimes messes with the entry angle of the screw. Make sure your threads are clean from any thread lock residue, shavings, dirt, etc. then try hand threading the screw without the grip. Once you've chased the threads or verified there isn't any damage, try to get the same entry angle through the grip.
Also, I don't think you can retap threads in aluminum without compromising the strength or going to a larger screw/bolt. The correct repair would be drill out the hole and insert a Helicoil. This is not something a manufacturer would do for you.
OK....thanks. Checking Google for "Helicoil" ... just in case. :)
Did you try some grease on the thread? It can make a big difference.
Follow the advice mark5pt56 gave above, it is the best way to install a grip.
OK....thanks. Checking Google for "Helicoil" ... just in case. :)
I'll save you the time, it's not something you can do yourself.
There is enough thread length that if it was cross threaded only a few turns the damaged threads could be drilled or countersunk out.
What's the worst case scenario if I have managed to screw up the threading in the aluminum receiver? I'm not saying I have, but...would I be able to return the receiver to the manufacturer and have them retap the threading or have I managed to royally F up the receiver to the point it is no longer usable? (Worst case scenario!).
Some lowers have the grip screw hole drilled all the way through.
-If your lower is drilled all the way through, remove the grip and the screw.
-Visually check for debris in the hole. Clean out any debris by blowing it out with air or brake cleaner or something.
-Put a light coat of grease on the end of the screw.
-From the top, run the screw through the hole until it goes all the way through. This will chase the threads, cleaning up any that may have been damaged.
-Remove the screw and clean the threads of the screw and hole.
-Carefully start the screw in the bottom of the hole without the grip in place to check the fit. Note how the screw feels as you run it down. This will give you a way to gauge if the screw is cross threading or not when installing the grip.
-Remove the screw and install as normal.
-Be patient. If it doesn't feel right, take it apart and figure out what's going on. You don't want to cause anymore damage.
Don't panic if the starter thread in the bottom of the hole is damaged. Just get it cleaned up enough to get the screw started. There is plenty of thread length to hold the screw in place. Don't use red Locktite! If you use Locktite, use blue. Apply only a little to the first couple of threads and, if possible, let it set before installing. The lock washer/star washer by itself will hold the screw in place just fine.
Read Mark's post before starting. It's good advice.
If you have stripped some of the threads, drill out the damaged threads and get a longer screw.
Assuming it is tapped all the way through.
Follow the advice mark5pt56 gave above, it is the best way to install a grip.
I'll save you the time, it's not something you can do yourself.
There is enough thread length that if it was cross threaded only a few turns the damaged threads could be drilled or countersunk out.
A HeliCoil, or better yet a TimeSert, is absolutely doable at home. A vise/fixture and steady hand or drill press will suffice. Did it to my aluminum brake calipers well known for for their galvanic corrosion because the OEM didn’t spec steel threaded inserts.
Is it better off getting done on a Bridgeport? Yeah, but a $50–150 AR lower probably isn’t worth trying buy someone’s machine time.
Thanks for the advice, I gave it another try last night. I'm working with an LMT lower receiver (pricey!), and there is no opening/but out from inside the receiver, near the trigger, etc.
I cleaned the threads inside the threaded hole and the screw itself.
I lubricated the screw hole and the screw and tried to get it to go in, but I hit a hard wall and I'm not trying to force it at that point.
Further, I'm using a screw that is for a flat head screw driver, and I've purchased a grip screw that is a hex head for better purchase with my torque driver.
Would you guys suggest once I get the new screw I just muscle it past the "block" or stopping point and take it from there?
As for the Helicoil/TimeSert I do have a vise (not a drill press).
Thanks for the advice, I gave it another try last night. I'm working with an LMT lower receiver (pricey!), and there is no opening/but out from inside the receiver, near the trigger, etc.
I cleaned the threads inside the threaded hole and the screw itself.
I lubricated the screw hole and the screw and tried to get it to go in, but I hit a hard wall and I'm not trying to force it at that point.
Further, I'm using a screw that is for a flat head screw driver, and I've purchased a grip screw that is a hex head for better purchase with my torque driver.
Would you guys suggest once I get the new screw I just muscle it past the "block" or stopping point and take it from there?
As for the Helicoil/TimeSert I do have a vise (not a drill press).
Never attempt to muscle it. That always ends in disaster for me.
You can get a tap and clean up the threads, that is probably the best option at this point.
Andy
In the cold light of day here and fortified by strong coffee I have decided to take it in to my gunsmith and let him fix it rather than risk absolutely destroying the LMT MARS-H lower I 'm dealing with.
If it was a cheap Anderson lower...sure, I'd be up for it, but ...
Never attempt to muscle it. That always ends in disaster for me.
Yup, and that is what I did. I tried to muscle it down once it first stopped moving. And...there you go. :)
Is there a pre applied thread locker on the screw? If, take a wire brush to it as they are usually generous with that crap. I would get the tap as mentioned. 1/4x28
In the cold light of day here and fortified by strong coffee I have decided to take it in to my gunsmith and let him fix it rather than risk absolutely destroying the LMT MARS-H lower I 'm dealing with.
If it was a cheap Anderson lower...sure, I'd be up for it, but ...
Before smiff I’d chase threads with tap like Andy noted.
Before that I’d do what Mark said, but threads in lower too as they make be “gummed” with locker.
Oof, I wouldn’t want to mess up a MARS-H.
Side note, where’d you get it? I’m looking for one.
I received a Colt Complete lower the pistol grip was loose when I picked it up.
Took it home and it was cross threaded or threads buggered. Contacted Brownells return slip,
ordered another one and it arrived JUST FINE.
If it was a cheap Anderson lower...sure, I'd be up for it, but ...
If it was a cheap Anderson lower, you would find they only tap part of the pistol grip screw hole and you would be mildly bitter about it. Easy to cut threads in the rest of the hole though.
Andy
OK, I wanted to circle back around again here and let you know how things turned out. I actually had an appointment scheduled at my gunsmith today.
I thought, "OK, settle down, give it a good think and try it one more more time.
Here's what I did.
I used a hex screw that I had in my parts bin, and did the following.
1) I first put it all the way into the receiver hole for the pistol grip. It went all the way in. I could feel it moving pasted the small area I had stripped, but then...it had a solid purchase.
2) I got a long hex wrench with a torque handle.
3) I greased up the screw and the hole, and then I inserted the screw into the pistol grip with the long hex wrench big I have in a DREMEL kit.
4) I carefully inserted the safety detent and the take down detent pin and springs on my LMT.
5) I carefully got everything in place and slowly started screwing it down and .... voila....it all worked.
My theory here it the following:
1) I simply was trying to rush it and I over-angled it when I first attempted it and stripped out some threading.
:)
Thanks for the great advice.
Live and learn.
Always start by turning the screw backwards to find the threads, then righty tighty!
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