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Hey FNF. (TL-DR at the bottom.) Another ‘stripped screw’ post here I suppose, but I’ve done all I can. I read up like crazy on this, and have arrived at a dead end, so I’ve decided to post up.

I’ve stripped the rear receiver screws on the left side of my SCAR 17, trying to remove them for the GG&G QD mount. I’ve read through lots of different ways to try and remove these stripped screws, and nothing has worked unfortunately, so I come to you guys. (Part # 216 on this SCAR Part List)

ScarScrew.jpg



Here’s what I’ve tried:
  • Soldering Iron Method: Heat up screw w/ soldering iron to burn off Loctite. Receiver dissipates heat, doesn't heat up screw enough to loosen Loctite.
  • JB Weld Method: Put JB weld in stripped hole, pressed in Allen wrench, let dry. Upon turning, Allen wrench didn’t grip and popped right out. Tried this twice, 1st time let dry overnight. 2nd time, let dry for a full 24 hours. Neither worked.
  • Easy Out Screw Extractor Method: Stripped receiver screw even worse. Reverse threads on extractor won’t grip stripped screw b/c it’s too shallow.
  • Rubber Band Method: Yeah… i tried it, and of course it didn’t work. Put rubber band in hole, pressed in Allen wrench, tears up the rubber band. Read this one online somewhere…
  • Hammer in larger Allen Wrench / Torx Socket Method: Hammered away, Allen wrench didn’t do a bit of good. However, the Torx socket made some ridges in the head of the screw, but still wasn’t enough grip to pull it out.
I referenced this thread by JL361, as his situation has been nearly identical to mine, with the exception that I’m trying to install the GG&G QD mount, not uninstall it.
He ended up having to take his to a gunsmith, but didn’t post what the gunsmith did to get the screw out. (I PM’d him asking as well, no luck, no response.) I’ve spoken with a few local gunsmiths, and most of them are saying to send it back to FN for repair, as they don’t want to damage the receiver, and there’s my problem.

I called FN and they told me they'd never heard of one of these screws being stripped. The guy must have been new, b/c if you Google "SCAR Screw," you come across tons of results regarding stripped screws. I asked if I could send it to them and they remove the stripped screw, and just leave it out, and then send back to me, and they said they couldn't do that. He said any repair that comes in has to be repaired to their original specifications, and then they send it back out. Meaning they'd remove the stripped screw, put in a new screw and throw in more loctite. I also asked what kind of loctite they used, if it was the green, and the guy said it's closer to the red (which requires heat for removal.)

So I asked them if they could send it back without the loctite at the least. They said no to that as well. I then asked if they could install the QD mount for me. Again, they said no. So I follow that up asking how much it would be to send it in to get the screw out, and they said it was estimated at $80 at minimum.

I then called GG&G, and they told me to take a soldering iron and hold it to the screw for 10-15 minutes until it started smoking. They said that when I saw smoke, that was the loctite burning up. After it burned up, it would not re-solidify, and would stay as a powder, and the screw should come right out. Held a soldering iron on the screw for 15 mins, nothing. Then 30 mins, nothing. The screw gets hot (as felt from inside the receiver,) but since it's in the metal receiver, the receiver acts as a heat sync and disperses the heat, rather than focusing it all onto the screw.

And therein lies the problem. I can't take a small torch to it, b/c that'll heat it up too much and harm the anodizing. And a soldering iron won't heat it up enough to burn off the loctite b/c the receiver dissipates the heat. But Loctite recommends using a torch to heat up threading that red Loctite was used on...

In looking into the temperature that anodization can handle before becoming damaged, I found that it has very low thermal conductivity. As a result, the coating will crack from thermal stress if exposed to temperatures above 80 °C (or 176°F.) The anodizing can crack at that temperature, but will not peel. Propane and butane torches generally burn at an average temperature of 3,600 °F, well over 176°F.


What's next?

I've thought about doing the 'drill out' method, where you take a drill bit smaller than the diameter of the screw, and drill out the center so the tension releases, but this would be risky and need a really steady hand, as to not damage the back plate (Part # 215 on this SCAR Part List)

I've also even thought about taking foil and 'masking off' around the screw, but... that's just asking for trouble, since a torch would more than likely still overheat the anodizing through dissipation.

I've heard of people drilling & tapping stripped screws to get them out, but have no experience in this. And I've also heard of people welding a nut onto a stripped screw, and using a wrench on the nut to get the screw out, but I have no experience welding (I wish.)

Any advice appreciated.

--

TL-DR - Have tried multiple methods in removing stripped receiver screws, none have worked (see bullet points,) seeking advice how to remove stripped screws without damaging the SCAR receiver.
 

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Probably not helpful, but what kind of soldering iron are you using for heat? When I solder rf connectors, I have the same issue with conducting heat away from the work before the job gets done, when using an electronics or gun type iron.

I use a "heavier" density iron, about the size of your little finger in diameter, and let it preheat before tinning. This usually allows it to store the heat to a point I can heat the work and to the job before heat dissipates. They also have a heat sink paste available, that can suck out the heat conducted to the surrounding area needing protection that might protect your anodizing, etc.

just a thought.

pacer
 

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Legion:
That screw head looks pretty gouged, so at this point, drilling out the screw may be your best option. You can do this on a drill press at slow speed if you rig up a wooden jig or some other way to hold the receiver so that it doesn't move around and allow the bit to jump from the center of the steel screw to the soft aluminum receiver. Unless you have the equipment in your work shop and experience doing this task, paying a reputable gun smith would be the safest way to accomplish it. The $50-100 cost is a lot less than the value you will lose if you gouge the receiver and the gunsmith can loosen the other one for you as well while he has the receiver. Let us know how you solve it.
 

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Are you using a variable voltage soldering iron or one of those cheap 15w ones from radio shack? The hotter you can get the iron, the faster it will work and you won't be keeping it on there long enough to damage anything but the loctite.
 

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Man, you did a real number on that screw. I would carefully cut a slit in it and use a flat head but you will still have to break the loctite with heat first. I used a little torch on mine. I was careful and the anodizing looks just fine. Even with plenty of heat, it slightly bent my allen key and damaged the screw some. I was really surprised how hard it was. It might be best just to send it in and get a fresh start. I really like the GG&G mount. I think its the cleanest looking mount and works well but it can be a $%^&&* to install.

Did you ask ggg if they were willing to install it for a fee?
 

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Discussion Starter #9
Probably not helpful, but what kind of soldering iron are you using for heat? When I solder rf connectors, I have the same issue with conducting heat away from the work before the job gets done, when using an electronics or gun type iron.

I use a "heavier" density iron, about the size of your little finger in diameter, and let it preheat before tinning. This usually allows it to store the heat to a point I can heat the work and to the job before heat dissipates. They also have a heat sink paste available, that can suck out the heat conducted to the surrounding area needing protection that might protect your anodizing, etc.

just a thought.

pacer

It's an electronics soldering iron, not that heavy duty. Never heard of this heat sink paste, might have to look into that, especially if it's able to concentrate the heat.



Legion:
That screw head looks pretty gouged, so at this point, drilling out the screw may be your best option. You can do this on a drill press at slow speed if you rig up a wooden jig or some other way to hold the receiver so that it doesn't move around and allow the bit to jump from the center of the steel screw to the soft aluminum receiver. Unless you have the equipment in your work shop and experience doing this task, paying a reputable gun smith would be the safest way to accomplish it. The $50-100 cost is a lot less than the value you will lose if you gouge the receiver and the gunsmith can loosen the other one for you as well while he has the receiver. Let us know how you solve it.
Yeah, I was putting a lot of my marbles in the screw extractor working, but that made it much worse. Didn't grab at all.

Unfortunately no access to a drill press, and don't know of any friends that own one. Trying to rind a reputable gunsmith has proven to be a bit difficult though, but still hopeful.

Are you using a variable voltage soldering iron or one of those cheap 15w ones from radio shack? The hotter you can get the iron, the faster it will work and you won't be keeping it on there long enough to damage anything but the loctite.
I'll have to look into investing into a better one it seems. You're the 2nd one mentioning it. Any recommendations? :)


You could possibly use a Dremel tool to cut a slit in the top of the screw and then use a flathead but a drill press might be the only way
Have thought about this, but even then, still need to heat it up to remove the loctite. Additionally, having used dremels many times before, it's very easy for them to suddenly get away from you and cause unintended damage, especially with something so small.

I used a little torch on mine. I was careful and the anodizing looks just fine. Even with plenty of heat, it slightly bent my allen key and damaged the screw some. I was really surprised how hard it was. It might be best just to send it in and get a fresh start. I really like the GG&G mount. I think its the cleanest looking mount and works well but it can be a $%^&&* to install.

Did you ask ggg if they were willing to install it for a fee?
What torch did you use on yours, if you don't mind me asking, and how long did you keep the flame on the screw? Assuming it was a pen style flame? Did you use anything to mask off the anodizing, or just concentrated it directly on the screw?

That's pretty crazy to know even after you applied heat with a torch that it still bent your allen key.

In looking at lots of other mounting options, I liked the GG&G the best, hence why I went with it. As you said, cleanest looking mount and works well. I already had a dual point QD as well, so it fit the bill. But yeah, these screws are a total pain.

Didn't think to ask GG&G if they'd install it for a fee. Might have to call them and ask, but I'm betting the answer's probably not. They'd have to be a licensed FFL to accept the firearm, which they possibly might be. Even if I sent just the receiver, since it's the serialized part, I'd think that'd count as the firearm?



Thanks all for the input and recommendations, very much appreciated.
 

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Sorry, I just remembered That I used a heat jet/gun function. A pen-like torch probably would have worked as well or a good soldering iron. I have a pretty nice soldering iron that converts from a soldering iron,heat gun, or torch. I used it as a heat gun. Not sure of the temp but I cranked it until the heat gun tip was glowing red and held it on the screw until I saw the loctite smoke. I was surprised what it took. Like you said, the receiver acts like a heat sink and was dissipating the heat more than I expected. I was worried about cooking the anodizing as well but it turned out fine.

Good luck. Let us know what you end up doing.
 

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Just went through this-on the same screw.

You need a heat gun. Chinese tool store brand will do(I'd spring for the one with 2 range and temp setting). You need to heat the screw from the inside of the receiver until it reaches 400 degrees. (Got this info directly from Sarge)

I tried all the methods you did to no avail. Also taped up the area thoroughly and dremeled a flat head slot...and it chipped and dug out without moving. I ended up removing the rail covering the inside of the screw(I felt it was preventing it from heating up enough), hitting the screw with PB Blaster, drilling almost 4/5 through the screw with a 5/64 and 3/32 bit, pounding in a T15 torx bit with a tack hammer and ratcheting it out with a 1/4" ratchet-after heating it again with the gun. Came out with no damage or marks on the receiver. Did nick the edge of the first thread on the butt plate, but it was insignificant and checking with a new fastener engages all the thread tightly.

I was sweatin' bullets the whole time! In my case there are no gunsmiths in my area. And I'm not leaving a Form1 rifle at a machine shop. I'm not sure that Form 1ing my rifle voids my warranty with FN, but I didn't even want to go down that road.


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Discussion Starter #12
Sorry, I just remembered That I used a heat jet/gun function. A pen-like torch probably would have worked as well or a good soldering iron. I have a pretty nice soldering iron that converts from a soldering iron,heat gun, or torch. I used it as a heat gun. Not sure of the temp but I cranked it until the heat gun tip was glowing red and held it on the screw until I saw the loctite smoke. I was surprised what it took. Like you said, the receiver acts like a heat sink and was dissipating the heat more than I expected. I was worried about cooking the anodizing as well but it turned out fine.

Good luck. Let us know what you end up doing.
Awesome, thank you for the information, much appreciated. Will keep the thread updated :?




Just went through this-on the same screw.

You need a heat gun. Chinese tool store brand will do(I'd spring for the one with 2 range and temp setting). You need to heat the screw from the inside of the receiver until it reaches 400 degrees. (Got this info directly from Sarge)

I tried all the method you did to no avail. Also taped up the area thoroughly and dremel a flat head slot...and it chipped and dug out without moving. I ended up removing the rail covering the inside of the screw( I felt it was preventing it from heating up enough), hitting the screw with PB Blaster, drilling almost 4/5 the ought the screw with a 5/64 and 3/32 bit, pounding in a T15 torch bit with a tack hammer and ratcheting it out with a 1/4" ratchet-after heating it again with the gun. Came out with no damage or marks on the receiver. Did nick the edge of the first thread on the butt plate, but it was insignificant and checking with a new fastener engages all the thread tightly.

I was sweatin' bullets the whole time! In my case there are no gunsmiths in my area. And I'm not leaving a Form1 rifle at a machine shop. I'm not sure that Form 1ing my rifle voids my warranty with FN, but I didn't even want to go down that road.

Nice, thanks for that temp info! Wasn't wanting to use a dremel to do the flat head slot method, but seems it's coming down to that option.

How did you remove the rail covering the inside of the screw? The rail seems to be held in by a number of screws on both sides of the receiver, and I'm assuming they all have this loctite on them, or is that incorrect? Being able to remove that rail on the inside would be great, as I wouldn't be as worried about drilling out the screw with a smaller bit.

Glad it worked out for you, and thanks for sharing this information. I've hit it w/ PB Blaster already as well, and let it marinate, but no luck. Seems I just need to get a descent heat source on it and melt that damn loctite at 400-deg:???:
 

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I remove the rail with little difficulty using the method mentioned- heating the screwFROM THE INSIDE and unscrewing then with an L-shaped Allen wrench(2.5mm). Make sure it's good and heated. Note; the flathead method didn't work for me. Had to use the torx fitting to lodge in there and get it out---to be honest-I don't think the torx was that well lodged in there--just drilling through it relieved the tension on the threads.


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Another option you can do is just get a Parker Mountain Machine QD socket. It mounts through the standard sling loops right above where the GG&G one goes so the position is almost identical. I have the GG&G one and really like it, but the PMM one seems good too. You'd have to buy it, but if you haven't damaged the GG&G one you can return it and cover the cost of the PMM (not to mention I'm sure you have already spent more on tools and repair equipment than you would have on a new mount).

I fully understand and support the "well now it's a matter of principle" argument and not wanting to get beaten by a stubborn screw, but if you're cool with cutting your losses it would be a very quick and painless solution. I would just touch up the stripped screw with black paint, otherwise the stripped metal would make me mad every time I looked at it. I know it's not a perfect solution, but if your end goal is to have a QD socket at the rear of your receiver, that's probably the quickest and easiest way to get there. Good luck,

H
 

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Discussion Starter #16
I remove the rail with little difficulty using the method mentioned- heating the screwFROM THE INSIDE and unscrewing then with an L-shaped Allen wrench(2.5mm). Make sure it's good and heated. Note; the flathead method didn't work for me. Had to use the torx fitting to lodge in there and get it out---to be honest-I don't think the torx was that well lodged in there--just drilling through it relieved the tension on the threads.
So you heated each screw holding that rail, and removed them. Am I reading that right? Sounds like a lot of work :p

I've heard that the drilling method has worked for a few, so that might be the route. Thanks for the clarifications!


Where are you located (generally)? That will help with smith recommendations.
Central Florida, Orlando'ish


Another option you can do is just get a Parker Mountain Machine QD socket. It mounts through the standard sling loops right above where the GG&G one goes so the position is almost identical. I have the GG&G one and really like it, but the PMM one seems good too. You'd have to buy it, but if you haven't damaged the GG&G one you can return it and cover the cost of the PMM (not to mention I'm sure you have already spent more on tools and repair equipment than you would have on a new mount).

I fully understand and support the "well now it's a matter of principle" argument and not wanting to get beaten by a stubborn screw, but if you're cool with cutting your losses it would be a very quick and painless solution. I would just touch up the stripped screw with black paint, otherwise the stripped metal would make me mad every time I looked at it. I know it's not a perfect solution, but if your end goal is to have a QD socket at the rear of your receiver, that's probably the quickest and easiest way to get there. Good luck,

H
That's incredible, just did a google search for these, was not aware they were available, and for so cheap! Huge thanks for that recommendation. :mrgreen:

Have spent some money on methods trying to get this thing out, but some of them were tools I needed anyways, so think I'm able to justify it in that sense.

Definitely a matter of principle, but I'm not one to let stubbornness get the better of me, especially if it's impacting the wallet, haha. Will look further into this, thanks again for the heads up! :?
 

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Another option you can do is just get a Parker Mountain Machine QD socket. It mounts through the standard sling loops right above where the GG&G one goes so the position is almost identical. I have the GG&G one and really like it, but the PMM one seems good too. You'd have to buy it, but if you haven't damaged the GG&G one you can return it and cover the cost of the PMM (not to mention I'm sure you have already spent more on tools and repair equipment than you would have on a new mount).

I fully understand and support the "well now it's a matter of principle" argument and not wanting to get beaten by a stubborn screw, but if you're cool with cutting your losses it would be a very quick and painless solution. I would just touch up the stripped screw with black paint, otherwise the stripped metal would make me mad every time I looked at it. I know it's not a perfect solution, but if your end goal is to have a QD socket at the rear of your receiver, that's probably the quickest and easiest way to get there. Good luck,

H
That's the route I went. I installed the GG&G on my 16 without issues. When I tried the intstall on my 17, one screw came out easily...the other stripped like a 16 beer drunk. I didn't have the tools needed to to extract the screw myself and took the easy way out. I ordered the PMM mount. Sure, you can call me a quitter, but it was a no headache solution...and one I'm quite happy with.
 
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That's the route I went. I installed the GG&G on my 16 without issues. When I tried the intstall on my 17, one screw came out easily...the other stripped like a 16 beer drunk. I didn't have the tools needed to to extract the screw myself and took the easy way out. I ordered the PMM mount. Sure, you can call me a quitter, but it was a no headache solution...and one I'm quite happy with.
How do you like the PMM? Assuming it tightens down pretty solid, no rattling around?

Wouldn't call you a quitter. I might have before having this stripped screw happen to me personally, but after, I'd call it smart ;)
 

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How do you like the PMM? Assuming it tightens down pretty solid, no rattling around?

Wouldn't call you a quitter. I might have before having this stripped screw happen to me personally, but after, I'd call it smart ;)
I'm very happy with the mounts. Solid with no rattle at all. I was happy enough that I replaced the mounts on my 16 with the PMM also. Of course that's also because I have a touch of OCD and wanted my 16 and 17 to be a similar as possible.
 

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Since this thread helped me when I started researching after finding my rear receiver screws wouldn't budge, I'm adding this for future searchers.

You need a heat gun. Chinese tool store brand will do(I'd spring for the one with 2 range and temp setting). You need to heat the screw from the inside of the receiver until it reaches 400 degrees. (Got this info directly from Sarge)
This is what did it for me. Picked up a $20 two-setting heat gun from Home Depot (Wagner HT1000), put heat to the front and back of the screws using the high setting for several minutes, and the screws dislodged using moderate force with a 2.5mm hex tool.
I did not readily see smoke from the threadlocker breaking down, but as I was wearing a headlamp, I could see very faint smoke in the beam of my light.
The receiver does dissipate a lot of heat, it was too hot to touch by the time the screws released, I was holding the assembly by the MREX handguard.
 
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