How to fix stripped threads on my Impact

[Michael]

I forgot to turn down my torque wrench before reinstalling my trigger guard. What are my best options to fix this?

Retap the threads (what size)? Purchase slightly larger or coarser threaded bolts (what size)?

I can’t be the only one to have done this!

 

[Centercut]

Get a HeliCoil kit... Comes with drill and tap. Not sure what size they are...? M4? You drill out the hole, tap the hole, then insert the helicoil and you're back in business... This way you can use the same size screw...

 

[woogie_man]

Those screws are M3x16 socket head screws. You could get a Helicoil kit like centercut mentioned, or you could drill the hole a little larger and retap for an M4 bolt.

Which bolt was it? Because honestly with the 4 that are there you would be ok with one missing. I know that is less than ideal, but the other three bolts are more than strong enough to hold the bottom rail.

 

[Ca_Varminter]

Helical.... the easiest and economic way..

More expensive Time-serts..This system use a solid threaded insert..
It does require more machining prep......
Also more clearance for the insert.

I did this as a preventative measure on the 10/22 I machined..the Stock screw

 

[corny]

And if u really want to go crazy…u can go with an oversized thread sert. Those things hold better than the original thread

 

[jmohme]

The problem with inserts is their OD. You have to watch that by the time you drill and tap, that there is enough material left of the base metal around the entire circumference of the screw hole.

 

[Bigragu]

This is what you need, Mike, for M3 fasteners. That’s 4 for the trigger guard screws, the 18 on the top plate(including 4 for cheek rest and the 2 for the scope rail)and 14 that surround the rear block.

You can buy additional inserts above what already come in this kit. M3 x 5mm(length)

https://www.amazon.com/gp/aw/d/B0092QUMBK?psc=1&ref=ppx_pop_mob_b_asin_title

This will allow you to reuse M3 fasteners. The hole gets drilled bigger to accept the helicoil. Set the helicoil just below the surface by like one coil. Don’t forget to snap off the wire tab at the bottom after competing the insert

 

[trlrman]

A piece of zip tie or fishing mono the depth of the hole might get you out of a bind ?

 

[DesertSilver]

Go with the heilcoil. Time sert while it will give you a much stronger thread might compromise the strength of the part being repaired.

 

[SteveV]

Are the threads completely stripped, as in totally gone? If not and you just have "buggered it up" a thread chaser might do the trick. One saved my ass when I thought I had stripped the cast iron head of my truck when over torqing a spark plug. Might be worth a shot!

 

[Airgun-hobbyist]

Michael, which actual hole is stripped, the one in front of the trigger or the one back by the grip? I'm looking at my Gen1 Impact...

If it is one of the screws in the front of the trigger, there may be limited room to drill deeper (depending upon the overall outside diameter of the threads in the bottle adapter). It has been too long to remember the size of those threads on the adapter to give a definite answer, but there may be room to go deeper there. However, on a positive note, there is already enough room there to clean up the threads and make a few more with a bottoming tap. Then you just need a longer screw.

If the screw hole back by the grip is stripped, there is definitely room for deeper drilling and tapping. It too is already plenty deep for simply getting a longer screw. Doing the job would still require a bottoming tap to clean up the deeper threads.

A standard ground Erwin brand tap from any hardware store will work to clean up the initial threads. Then grind the tip of the tap shorter to make it go deeper (a bottoming tap).

Use a light hand when tapping. Go into the old threads easy, backing the tap out as necessary to clean the threads, then going back in easy. Do as I did with a depth gauge to know where you are at so you don't over do it and snap a tap.

As far as going to a bigger diameter with a thread repair product, there is very limited room for that on the front screws, because the new head size may interfere with the foster fitting. The rear screws are already at the border of being too big based on the width of the guard.

Johnny deeper.

In the pictures... Notice the two different depths? The longer is the back hole.

 

[Michael]

Thanks for the tips everyone! It's not critical as I just used it for our NEW monthly target shooting challenge! But I would like to fix it eventually. Think I'll try a Helicoil kit first.

 

[Healthservices]

What's good about doing it on a gun is, it is small and many times can be put in a drill press with a good vice. That way you can make sure it is perfectly straight when you drill the threads out and run a tap in, or in my case drilling out a stripped out screw.

Although it was a ratty old 25 year table top drill press, it got the job done. Probably invest in something better and bigger if I come across one. Take your time and it won't be a big deal.


Allen

 

[Airgun-hobbyist]

@Michael what did you do to fix this issue?

 

[2L8]

@Michael
Just get a new M3 (however that maybe). No mucking about figuring out details...Problem solved

Patrick

 

[Harv24]

Where was this thread a week ago....While working on my Brocock Concept XR, I noticed the folding stock was wobbly. After removing the trigger guard/pistol grip assembly, I saw the two M3 screws were loose. One tightened, and the other kept spinning...damn it.

After debating what I wanted to do, I retapped the hole for the next larger size thread and reprofiled a screw close to the OEM and was good to go, I never even thought of a Heli-coil until you guys mentioned it.
I will keep that in mind for the future.