I have a year-old 629 Competitor. Problem is, after every six rounds (normal commercial loads), I have to re-tighten the screw that holds the thumb piece which releases the cyclinder. Apparently, the vibration loosens it. My thought is to apply some Loctite Blue. Is there any reason I should not do that? Is there a better way?

Am I unreasonable in thinking that for a $1500+ gun, S&W should have figured this out?

Blue would be fine. Be sure to de-grease the threaded portion of the bolt and inside the nut, then put a small amount of the threadlocker on the threads inside the nut using a toothpick.
You don't want excess fluid to wick down into the action. Leave the gun thumbpiece side down for the material to dry overnight.

Perhaps, but some fittings are prone to work loose....and there are strong harmonics at work on that subassembly.

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Ret. LE, FA Instr, S&W Armorer

I had the same problem till I lost the nut, ordered a new one and haven't had a problem since.

Sent from my SM-T800 using Tapatalk

Ive used a small piece of teflon tape in similar cases.

I have a M29 that I got used from this forum, and immediately after I got it after maybe 20 rds of magnum I lost the cylinder release nut and thumbpiece, the front screw of the rear sight was working its way out, and the cylinder stop screw was coming loose.

The previous owner, who frequents this forum and seems like a great dude, said he mostly shot 44 SPLs. I'm honestly not blaming him at all, my point is there's a BIG difference between SPL and MAG. Magnum rounds are a whole 'nother thing, and the gun has to be up to the challenge.

FWIW, I replaced the original with an SDM aftermarket release that was supposed to provide more traction, but honestly the difference seemed pretty minimal. I also used a dab of blue Loctite to lock it down.

I had a 625 that the yoke screw, cylinder release, strain, and side plate screws all came loose after 50 rounds of .45acp... With .45Supers; forgetaboutit! The strain screw backing out caused light primer strikes which really pissed me off since this was going to be my dedicated "woods gun" at the time and potentially could have gotten me killed. But then again, this happened at the range because proofing a new pistol is prudent before stuffing it in a holster and heading to the great outdoors... Purple Loc-Tite is what you seek OP. Remove the screws, degrease the screw hole and screw thoroughly... dry, then add a dab of the Purple Loc-Tite to one side of the screw threads and torque it down 1/8 to 1/4 turn past snug. Once I did that I put witness marks with a white out "Sharpie" and proceeded to run 100 .45Super's thru the 625. None of the aforementioned screw budged a hair.

^^^^^What Hamhands said. Purple is plenty strong enough for the job. Use the blue & you might wish you hadn’t down the road.

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Don't You Ever Wash That Thing

Purple is for locking up to 1/4" thread size. Go to Blue for 1/4" to 3/4" thread size. There really is no place for Blue on S&W revolvers unless you shake, rattle and roll all the time.

Stu

Blue is perfectly fine for gun screws. It is easily removable with a screwdriver or appropriate wrench with no heat. The red and green are much stronger and require serious heat (over 350 F) to dislodge.

I use purple threadlock on the thumbpiece nut on both my 629 and my 29s. All three loosen up. Haven't had any other screws come loose yet.

On parts that get really hot during operation I've used "Blue" Loc-Tite before. Case in point... When I installed a low profile gas block in order to free float my scoped "Recce" clone AR-15... I used the Blue Loc-Tite on the (3) set screws for the gas block. Purple Loc-Tite probably would have been more than fine but considering temps that barrel gets at the gas block it was a safe bet. I used witness marks on said set screws and would check them every 250 or so rounds. None of them have budged a hair. I don't think it's necessary on a revolver though. YMMV...

Diesel, have you had any screws back out once Purple Loc-Tite was applied??? I'm a little rough on my carry pieces. Rough in the fact/way that I use them hard in practice but never, ever abuse them. After all, my girls and my life depend on my revolvers so they get TLC and proper maintenance after said range/training days. I've not had one screw in my "J" or "N" frame revolvers back a smidgen once I started using Purple Loc-tite. It's been a Godsend for my uses!

Just want to thank everyone for the responses. I started looking at the differences between Blue and Purple Loctite. I noted that Henkel recommends Purple for firearms and small threads generally. I also came across Vibra-Tite (Vibra-Tite VC-3 as a firearm threadlocker). Anyone have any experience with that?

No thumbpiece nuts have backed out after using purple threadlock. My post made it sound like they did but that isn't correct. They did keep loosening with no threadlock but not since I applied it the first time.

Vibratite is a good product, but hard to undo if you need to. Blue or purple Loctite is easier to deal with when it comes time to take it apart.