AR Sponsor
Posted: 12/10/2011 1:45:41 PM EDT
| I'm pretty sure that I cross threaded my lower where the grip is screwed in. It looks like the first few threads. Can this be fixed or do I need to start shopping for a new lower? |
|
Thanks for the replies. I'm feeling a little better that there's is a possibility that i can fix it. My Department has an Armorer/Smith that can probably do the repair or at least steer me in the right direction but I don't want to bug him on the weekend and it's a long time until Monday. I figured it could be re threaded but it wasn't sure because it's aluminum.
|
| If the grip screw hole is continued all the way into the lower. Just start turning the screw in from the inside of the lower. You might need to get a longer screw with the same thread pattern, or if your already going out, you can just pick up a tap and dye set. |
|
Quoted:
The first thing I would do is see if i could get the right size tap for the hole and very gently try yo rethread the existing hole. It can be done. Next would be the next hole up and then get the tap for that and last helicoil it. This. Always try the proper sized tap first. You may have a minor problem. Dave N |
| Without the grip on the lower, thread the screw in by hand until it stops. With the lower firmly supported in a vise, give the screw a good whack with a small ball peen hammer. See if it feels loose and try to thread it in if it is. This will sometimes "right" the screw in relation to the threads. |
| definitley go buy a 3.00 tap at the store and give it a try..I think they are 1/4 28 thread but someone can confirm this for you..If it is only the first few threads there should be no problem fixing em up..Heli coil will work fine also if they are that bad... |
|
First of all relax, You're in good hands and it can definitely be fixed.
Rethread it first and if that doesn't work, get a helicoil kit from McMaster-Carr or Grainger. It's not really a big deal. If you helicoil it, you could probably suspend your car from the grip screw. |
|
If it's a blind hole, buy a bottom tap. If it's only the first couple of threads, you should be able to tap S-l-o-w-l-y.. The best method I know of, is to go to a well stocked hardware store, not lowes, but one that caters to machine trades, quality taps, quality mic's calipers, etc. They make a piece that's T shaped. The top protrudes up and chucks up in a drill press. Put the workpice in a vice, insert tap in to lower part of the tap holder, and chuck top part into drill press.
Then turn handles on tap, slowly, when you have the pieces lined up properly. This keeps the tap straight. DO NOT turn on drill press, just turn T handle by hand. This tool can be had for about 20 - $25 bucks, but can be used forever, and this has saved my butt many times, by not letting the tap walk, while turning it. They generally fit taps from tiny to about 1/2 inch. Can also be bought at Brownells, if you don't have a local store that has a lot of machinist tools. Just a suggestion. FT |
|
Try threading a screw in from the top, to chase out the damage at the bottom, then see if you can get a screw started correctly.
This is the reason why the milspec slotted head screws suck. Use a hex socket cap screw and a T handle driver, and back up the threads correctly, then no chance of cross threading. |
|
Quoted:
Try threading a screw in from the top, to chase out the damage at the bottom, then see if you can get a screw started correctly. This is the reason why the milspec slotted head screws suck. Use a hex socket cap screw and a T handle driver, and back up the threads correctly, then no chance of cross threading. This is the best and easiest repair, except I would use a tap instead of the screw from the top. You will need to partially strip the lower receiver to get to the top side of the hole (it should not be a blind hole, and should be fully tapped). IIRC, it is a 1/4" coarse thread. Just take the screw with you when you buy the tap. |
|
Quoted:
The first thing I would do is see if i could get the right size tap for the hole and very gently try to rethread the existing hole. It can be done. Next would be the next hole up and then get the tap for that and last helicoil it. This. Chase it with a tap and little oil. Probably gtg. Pretty sure it's 1/4-28 |
|
Quoted:
Let me guess. Magpul grip with that stupid slotted head screw dabbed in blue locktite?? If so, use the original grip screw with the star washer and throw the Magpul screw in the trash can. Have to agree. That Magpul provided slotted screw is the biggest POS ever. If they insist on using a slotted screw they should give something with a little meat on it instead of that shallow slotted 1 cent screw they send. |
|
Quoted:
Quoted:
Let me guess. Magpul grip with that stupid slotted head screw dabbed in blue locktite?? If so, use the original grip screw with the star washer and throw the Magpul screw in the trash can. Have to agree. That Magpul provided slotted screw is the biggest POS ever. If they insist on using a slotted screw they should give something with a little meat on it instead of that shallow slotted 1 cent screw they send. The hex head screw and driver is so much easier and safer to use it's not even in the same league. |
|
Quoted:
Quoted:
The first thing I would do is see if i could get the right size tap for the hole and very gently try to rethread the existing hole. It can be done. Next would be the next hole up and then get the tap for that and last helicoil it. This. Chase it with a tap and little oil. Probably gtg. Pretty sure it's 1/4-20 It's 1/4-28, same as a Remington 700 stock screw. Quoted:
definitley go buy a 3.00 tap at the store and give it a try..I think they are 1/4 28 thread but someone can confirm this for you..If it is only the first few threads there should be no problem fixing em up..Heli coil will work fine also if they are that bad... This. Quoted:
The hex head screw and driver is so much easier and safer to use it's not even in the same league. QFT. |
|
Quoted:
Quoted:
Quoted:
The first thing I would do is see if i could get the right size tap for the hole and very gently try to rethread the existing hole. It can be done. Next would be the next hole up and then get the tap for that and last helicoil it. This. Chase it with a tap and little oil. Probably gtg. Pretty sure it's 1/4-20 It's 1/4-28, same as a Remington 700 stock screw. Quoted:
definitley go buy a 3.00 tap at the store and give it a try..I think they are 1/4 28 thread but someone can confirm this for you..If it is only the first few threads there should be no problem fixing em up..Heli coil will work fine also if they are that bad... This. Quoted:
The hex head screw and driver is so much easier and safer to use it's not even in the same league. QFT. Oops, my bad. I meant 1/4-28. Good catch. 
|
AR Sponsor