[Sticky] How to Treat Your Wooden Stock and Lock-Tite Your Stock Screws for Better Springer Accuracy---It's Easy, (but, A Lot of Words)
(Disclaimer: I'm sorry, I was absent the day they taught 'how to abbreviate a dissertation'--I would have asked someone else to do it for me, but they probably couldn't have stood to read it. I'll work on it). (If you can read through this, it will pay you some good dividends).
I definitely 'love me some springers', but springer accuracy can be daunting. We all know it, whether fan or foe. There are numerous reasons for that. They range from poor build quality to less-than-ideal hold technique, and everything in-between.
But, I've found that there's one common thread that sort of ties all the other accuracy problems together. It's accuracy problems caused by loose stock screws. You might think the solution is easy: just add a little (blue) Lock-Tite (or generic) to the screws, and snug them up nicely when you install them. Surely, that's going to take care of it, right!!?? Well, maybe not so fast...
I want to start by explaining both the root of the problem and its solution: First, let's assume that you already have your sighting system securely attached to the receiver--Allen screws, all that stuff. So, when I mention, "the receiver" here, I really mean both the receiver and its sights. So...
The Problem, Theory Explained: The stock is the part of a rifle you hold to--hopefully--send the pellet accurately on its way to target. Given: The receiver needs to stay aimed in the same direction you aim the stock, or none of it works right. That's because you don't hold the receiver, it's a separate part. You hold only the stock.
In an ideal world the stock and receiver would always function as a single unit, so that where the stock stayed or went, the receiver did, too. That works. OTOH, if the stock moves in one direction, and the receiver in another, it's going to be a problem. So we need to do something to prevent that from happening.
The Crux of the Solution--i.e. the Stock Screws: Since we don't dip our springer stocks and receivers into a giant vat of epoxy like we would some battered chicken into a big kettle of hot oil, we're forced to 'weld' the stock to the receiver in some other way. Specifically, we have to use our stock screws, usually only 3 or 4 of them, and they're rather small in comparison to the parts they hold and the job they have to do. We ask a lot out of them if you think about it, so, "What can we do to help them do their job in the best way possible?"
The answer is 'simple stupid', and by that I mean no insult to anyone. Now, if you're not having accuracy problems with your springer, and your stock screws are never loose when you check them, feel free to skip this post and have some fun doing something else. Obviously, you're already doing it right. But, some years back I read a method that was described on the Old Yellow for installing stock screws with thread-locking compound, and it was just wrong, period. I've never read anything that corrected the error, either. I would never drop a name. This post is about the method, not the person.
(If your stock is synthetic, you can skip the next couple of paragraphs, because so far I've never run into a synthetic stock whose material compressed under the stock screws like wood does. But, what follows after than about using Lock-Tite on the stock screws still applies. And, please read the "Caution" at the very-bottom of this post to avoid a dangerous situation that will arise if you misuse Lock-Tite on your synthetic stock).
First, Prepare Your Wooden Stock--Hardening the wood near the front screws on your wooden stock:
Before you proceed to install the stock screws themselves, the wood with which they are in contact needs to be hard-enough to keep it from being compressed by the screws when they're tightened, even after those screws have been in there for a good long while. Why? If the wood isn't hard-enough, even if you do everything else correctly, over time the wood will likely compress, and a gap will be left in-between the head of the screw and the wood. (Yes, even worse on soft beech than on hard walnut, maple, etc). When that happens, once again you have loose screws--not good. This primarily tends to be a problem on the front two 5 mm screws on the side of the fore-end of a stock, like the ones on the R1, HW77, RWS/Diana 34 as examples (I won't name them all). There's usually a lot more wood strength due to thickness where the main trigger guard screw is installed, so you can usually torque it down a little more without causing any serious damage.
Preparing to harden the wood: You'll need a small tube of 'runny' or 'thin' Super Glue C/A, 3 or 4 cotton swabs, a paper towel, and a small piece of 4/0 steel wool if you have a spill onto a surface that shows. Don't buy cheap or old glue--you'll be wasting your time. And, don't use the 'gel' versions of Super Glue/ cyanoacrylate--the gel isn't thin-enough to penetrate down into the pores in the wood, and that's what you're after.
For use after you've hardened the wood, you'll also want to buy two 5 mm metric flat washers, one for each side of the stock, to use in-between the head of the screw and the wood. (Screw cups with Allen screws are sort of a different animal, but hardening the wood is still the right thing to do).
Remove the receiver from the stock. If your stock has serrated lock washers on those front 2 screws, or has spring-type lock washers resting directly against the wood, I suggest you throw them away or use them for something else. The serrated type tends to fight you when you try to tighten a screw as much as it helps to keep screw heads from loosening, and either type can chew-up the wood pretty badly over time if it's in direct contact--that's where the new flat washers come in.
Getting ready to move: Give yourself some elbow room, because some of this next part where you apply the Super Glue needs to be done pretty-quickly, even-more-so if you're not too precise as to where you apply the glue, or how much glue you apply. You're going to be doing one side of the stock at a time.
Lay the stock down on either side first, and have the paper towel ready to soak-up any runs that occur onto the finish of the stock as quickly as possible. FWIW, I always wear a pair of reading glasses when I do this, because precision is a big plus. Drop about 2 or 3 drops of glue down onto the 'open' wood grain where the screw head rests when installed, and quickly whirl a cotton swab around the perimeter so the whole area is covered, and any excess glue is soaked-up. While the swab is still wet, you can swirl the swab around the ID of the hole itself to harden that part of the wood, too. That gives the area even more strength. (Note: I tend to stay ready to move my face away from the stock if necessary, because the C/A apparently reacts with polyurethane, and fumes often start to rise in a small plume of smoke. I don't know that breathing the odiferous gas is a good idea).
Immediately look-for any glue that runs down through the screw hole and wipe it up ASAP with the paper towel. Also, if you accidentally got some glue on the side of the stock that's facing the ceiling, wipe that off ASAP too. (Any small traces can be removed after the glue is set, with some VERY-careful buffing of the finish with the 0000 steel wool).
The glue will usually be fully-set in less than 1 minute at the most. At that point you can start any clean-up that needs done. Then, turn the stock over and repeat the same process on the wood down inside the other screw hole. With that, you're done.
Now, if you read all of that and can stand to read any further, this gets a lot easier. It still needs to be done right. This is where that method I read about on the Old Yellow fell short in a pretty-big way.
It said to carefully-de-grease the threads of the stock screws and in the receiver with something like acetone (correct), apply a small amount of Lock-Tite to both the male and female threads (correct, and I've found that a toothpick is very-good for removing any excess Lock-Tite on the threads), then install the screws until snug (yes), and let the rifle sit overnight before doing any shooting (nope-nope-nope--lol).
What's wrong with that?
If you do it exactly as described in that last step, after you've shot your first 5 or 10 pellets, the receiver will have immediately jumped-around inside the stock, and moved to its 'favorite', 'original', or hollowed-out spot inside the stock, and there will be gaps formed in-between the screw heads and the wood. That means all stock screws, front and rear. With the stock and receiver not able to remain in unison as was your original intent, inaccuracy will surely be the result. (You PCP guys are getting a good laugh out of this, aren't you? It's OK).
Instead, do it this way...
Actual Stock Screw Installation: Assuming you've already hardened the wood (if that applies to your stock), de-greased all related threads, and have applied the Lock-Tite to the threads, go ahead and install the screws and snug them up nicely. There's no need to 'gorilla-hand' the tightness of the screws, especially not yet, and especially if your screws have Allen heads. It's easy to over-tighten an Allen type stock screw if you're using the long-arm part of an Allen wrench, because it allows you to use so-much torque compared to a regular screwdriver).
Now, immediately shoot 5 or 6 pellets into a backstop or whatever, and check the screws again to see if they're still snug. If your rifle is like every one I've ever worked on, you'll be able to tighten the screws by another 1/10 of a turn or so. Then immediately shoot 5 more pellets, and check the screws again. They'll probably move just a little more, which is good. But, go ahead and do it a 3rd time. With that step, you probably won't get much more movement out of the screw head. That tells you the stock has 'found its home in the stock' for the most part. If you found you got a lot of movement in the previous tries, it won't hurt anything to do it again, etc. But, I think you'll soon find there's no more tightness to be had.
At that point you can let the Lock-Tite set-up as per the directions on the label. Even a few hours is pretty-good, but, yes, overnight is great.
After the rifle has sat overnight, you can check the screws one more time to see if anything has changed with any looseness of the screws. Keep in mind a couple of things about the blue version of Lock-Tite: 1. When you go to check it after its set-up, you may have to give the screw just a tiny bit more torque than you might think is necessary, to break the bond and allow the screw to move to its new position. 2. You might think that doing that (breaking the bond) will have destroyed the grip it can maintain on the threads, but IME that's not the case. The set-up compound that remains on the screws will hold again at its new position after being moved and still keep the screws tight.
It doesn't hurt to re-check the stock screws after 50 more shots, and maybe again after a couple of hundred more shots. If you see what I'm getting at, things should stabilize pretty-quickly with a little time and shooting.
I should add one last point: I mentioned that it can take a little extra torque to get a screw moving once it's been set-up in Lock-Tite, and that's true. But, it can be easy to mistake 'some needed tightening' for the crushing and thus damaging wood fibers under the head of a screw. So, again, while you want to have your screws properly-tight, you definitely don't want to damage your stock. I've seen that before: I had one stock come in here whose wood was so-thin at the front screw holes that I had to rebuild them to a proper thickness using JB Weld. It's even possible to pull a screw all the way through the stock at that front end location where the wood tends to be fairly thin. Then, a full-blow repair--like drilling out the wood and gluing-in pieces of a dowel rod--has to be done so the rifle can be shot again. When I send a tuned rifle back to a customer, and include a note to remind him to check the stock screws from time to time, I often tell him: think 'snug', NOT 'tight'.
If you use the above tips, I absolutely believe that you will eventually-encounter a springer somewhere whose accuracy was thought to be beyond reach, but that just needed the stock screw remedy(s) correctly-applied. (R7's et al are so-calm they aren't as subject to loose screw problems, and the R7/HW30s doesn't even have any screws on the front and sides of its stock). I think I can say this better: the harder recoiling your springer is, the more it will be subject to the screw-tightness problem I described, and the more important the solution I described will become.
(A caution re: the use of Lock-Tite on 'plastic' or 'synthetic' stocks, like the RWS 34 Panther, and some Gamo models, for instance: Lock-Tite and other thread-locking compounds with the same base liquid: Lock-Tite can dissolve a plastic stock, and it can do it fast! It says it right on the tube or bottle. If that happens, your air rifle may become dangerous to cock and or shoot. There was a case years ago where someone's Gamo stock dissolved/melted and when they went to cock the gun, the main trigger screw pulled-through the stock and the receiver hit them in the forehead, causing serious injury. You might want to search for another thread-locking compound that doesn't have the problem. Or, you might be like one of my past customers, and choose to use Teflon tape on your stock screws, instead. I own an RWS 34 Panther myself. In my case, I was able to avoid a problem by applying 2 thick coats of polyurethane varnish all around the areas wherever the Lock-Tite could come into contact with the stock material. I've had the gun apart since then, and there were no signs of damage). (End of this caution).
My thanks to Marc for suggesting his superior method to me of how to harden the wood near screw holes--the way I did it before I started using his method worked, but it took a lot longer.
You bring up an excellent point.
I've been asked about torque settings for stock screws a lot of times over the years. I've never given any. There's a good reason for that.
Steel, other metal, and even some plastics can often have such numbers assigned. But, in this case, we're usually talking about a material with one of the largest variables that exists: wood.
Not only do types of wood vary as to hardness (I.e. beech, walnut, maple, etc), but 2 different specimens of the same type of wood can be drastically different from one another. And, while I described hardening the wood with Superglue, the hardness of the end result will also vary.
Still, you want the screws correctly tightened. So, if not a torque wrench, which tool(s) do you use to set the screws? Two of the most important tools in your toolbox--the feel of the screwdriver in your hand, and experience.
As you tighten the screws, and in this case I'm mostly talking about the front 2 screws more than the others, you'll reach a point where you can feel the wood start to 'yield' under the torque of the screwdriver or allen wrench you're using. That's a good place to stop.
You've ceased successfully tightening the screws, and have started to compress (or, crush!) the wood under the head of the screw and/or flat washer. While a very slight yield is ok, more than that is counterproductive, or even destructive.
Any stock screws located on the bottom of the stock, like those at the trigger guard, usually won't compress the wood much, if at all. You probably won't have the problem I just described with those. That's because they're pressing against the edge or end of the wood grain.
OTOH, the screws on the side of the stock are pressing against the side of the grain of the wood. That's not nearly as hard as the edge or the end of it.
Crushing the wood: I've seen instances where the side screws have been tightened so much, the wood underneath them was compressed--crushed to be too thin for proper strength. Fortunately, in the ones I had here, I was always able to rebuild the wood with epoxy, then re-drill the hole.
Had the wood been any thinner, I probably would have had to drill larger holes all the way through the sides of the stock, and glue-in new hardwood dowels. Then the dowels would have needed drilled to accept the screws. Of course, the finish would have needed repaired. It can be done. But, ugh!
To sum up, IME, think in terms of what feels right, in place of using a torque wrench.
I followed your procedure to the letter for 2 HW50's & a 57. Replaced all star washers with flats. This is the glue that I snagged off Amazon:
Has consistency of almost water like and soaked into the wood easily, quickly followed with Q-tip to prevent any unseen build up. The tiny tips that came with this glue made applying very easy. Did have one streak that made it to the finish but as per your post, the 0000 steel wool made it disappear. Of course I was watching for that and got to it quickly. I did the exterior trigger guard area as well.
Tried the Vibratite but the Permatex blue Locktite seems to have better "hold" characteristics.
Then you did a pretty good bit of work. I hope it helped.