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Posted By: macrabbit Crack in stock Q - 01/13/07
My custom Rem 722's stock has a crack in the internal section between the middle action screw and the trigger group. Do I care?
FWIW, I see no indication that the screw contacts the wood. The crack is not quite complete to the bottom of the area, although I expect that if I pulled the sides of the stock apart at the mag box I could force it.
Posted By: Sitka deer Re: Crack in stock Q - 01/13/07
macrabbit
I would be very afraid of the bedding. Something is probably moving during recoil. I do not use the middle action screw and simply anchor the forward end of the trigger guard with a screw in the cracked web you are talking about.

If I were you I would simply rebed the whole action, cut out on either side of the crack and make sure the bedding fills that area. Replacing the middle screw would be my first concern however...

Once a crack show itself it is obvious the stock is being subjected to stress. It could be simple wood shrinkage or warping after the stock was built. Or worse, a case of improper bedding. Neither one will fix itself... But a simple rebed will fix both.
art
Posted By: Stuart Re: Crack in stock Q - 01/14/07
You might be able to repair it with Super T cyanoacrylic from Brownell's (made by CA Glues in Simi City, Calif.) Super T is the thinnest of three such glues they make- it's the consistency of water and will wick into a hairline crack. If you can open it just a tiny bit it will help, though. Run a little lacquer thinner in first to remove any oil in the wood.

I used this on a hairline crack in the wrist of my Marlin 1895 and it hasn't budged.

<img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> Stuart
Posted By: model70man Re: Crack in stock Q - 01/14/07
It worked well for me also. Thanks...Bill.
Posted By: Sitka deer Re: Crack in stock Q - 01/14/07
Cyanoacrylate has almost no shock strength. In gradual pulls it is great, but any vibration destroys it. If it appears to be working in a similar situation... ie. short cross-grain glue-up... it is because it was not really holding anything.

I use a lot of CA and it is great stuff for the right uses. The water-thin stuff wicked into punky wood will make it hard! The better stuff to use in a shock situation, if you have to try CA, is the Super thick formula. It has considerably more shock strength, though nothing near epoxy...
art
Posted By: macrabbit Re: Crack in stock Q - 01/16/07
Sitka, you used words that surprised me with their severity, so here are a couple of pics. Notice that the wood is well away from the middle screw. I don't see that any forces act directly on the cracked section.
The stock was made 30 years ago, is a wood to metal fit without any bedding compound (and will stay that way unless absolutely necessary). The 'smith, a family friend, passed years ago.


[Linked Image]

[Linked Image]
Posted By: Stuart Re: Crack in stock Q - 01/16/07
Quote
Cyanoacrylate has almost no shock strength. In gradual pulls it is great, but any vibration destroys it. If it appears to be working in a similar situation... ie. short cross-grain glue-up... it is because it was not really holding anything....

I'm surprised as well, but you obviously have quite a bit of experience with the stuff and know whereof you speak. Upon reflection, I can see that cyanoacrylates might be brittle, whereas epoxies are more flexible (relatively speaking.) I haven't tried abusing my Marlin 1895 so I don't know how it would take a sharp blow across the wrist, for instance. I do recall trying to pry the crack apart a little after the gue set up and it remained firm. so I have to conclude that it did the job. (The wood in the wrist was hard and dry.)

However, I know that AcraGlas is typically used for such repairs. The reason I didn't use it was that the crack was pretty thin and I was unsure if I could get it right down to the bottom.

FWIW, I did some searches on "thinning epoxies" and found a good article, originally by the people who make the West System epoxy products:

http://www.seqair.com/skunkworks/Glues/WestSystem/Thinning/Thinning.html

Their conclusion is that it is preferable to warm epoxy to thin it rather than using a solvent. Lacquer thinner (> 5%) seemed to work best in their tests but with adverse consequences to the strength.

<img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> Stuart
Posted By: DickD Re: Crack in stock Q - 01/17/07
Macrabbit,
Easiest thing here is just don't worry about it. Many stocks crack thru this little block, including our McMillan Fiberglass stocks. It happens because when you shoot the rifle the recoil impulse hits the stock at the recoil lug, and everything from the lug back flexes a little. The side walls of the stock along the magazine box actually flex out a little each shot and this pulls horizontally on this little piece of material, and it cracks. If it really bothers you, just cut the block out completely, it dosn't have to be there. It's really just there to support the front of an ADL trigger guard. Many inletting programs for other actions do not have any material at all between the trigger slot and the magazine cut out and they all work just fine. Dick D.
Posted By: macrabbit Re: Crack in stock Q - 01/17/07
Thanks.
That's the question, 'should I worry'.

I'm hoping Sitka pops back in and says that my pics explain better than my initial words, and that he'd not be concerned about the situation.
Posted By: stocker Re: Crack in stock Q - 01/17/07
Yes, indeed , they can crack in the web behind the magazine opening. Lots of them do. But the next area to begin cracking if you don't secure the back of magazine web is the area behind the trigger mortise and from there to the wood behind the tang screw. The same forces continue with every shot fired and if they cause the web to crack they don't always stop there (although some do). If you look at some heavy magnum rifles you commonly see two cross bolts installed. One supports the recoil lug and the other supports the web behind the magazine. Some really heavy kickers have a third crossbolt behind the rear guard screw. Their collective purpose at each location is to put the wood under compression and reduce the bowing/flex that can occur down the sides of the stock. The purpose of the large spanner nuts on these cross bolts is to achieve compression. A simple steel pin simply attached (epoxy usually)in constant diameter holes through the stock does not provid any compression and cracks can still occur.

On moderate recoiling rifles you can live with the split web for quite a while, perhaps indefinitely. On very heavy recoil rifles it is the sign of further things to happen that you won't like.

Either way it affects the rigidity of the union between rifle and stock.
Posted By: macrabbit Re: Crack in stock Q - 01/17/07
Your words aren't nearly as welcome as some from Ed McMahon and the Clearinghouse!

It's a lowly .257.


Sitka, why do you write of replacing the screw?
Posted By: stocker Re: Crack in stock Q - 01/17/07
mcrabbit: I think Sitka was referring to using a wood screw when using the ADL trigger guards rather than a dropping floor plate (BDL) style.

If it were my rifle I would at least repair the cracked area at a minimum. My glue of choice for these is still a good epoxy. If you carefully spread the crack you can usually get 100% glue coverage by using compressed air to get the glue distributed in the crack. No compressor? Buy a can of compressed air from a store that sells computers. It's used for blowing dust bunnies out of the tower.
You should also see if the recoil lug is making solid contact with the mortise and that the rifle isn't getting a running start at banging the stock. If there is any free space you should either glass bed the action and recoil lug as Sitka suggests or install some shim stock behind the recoil lug to push the action forward a bit in the stock.
Also check all your guard screw holes for sign of blackening/buffeting from the screws coming in contact with the wood as an indication of improper fit.
Do not over tighten the middle screw as that can cause a stress situation on the action which tends to force the stock sides apart.

As for it only being a 257, people use 257's in different ways. Some prairie dog hunters may shoot many times a day and deer hunters a lot less in a year than the varminter does daily. The recoil effects on the wood are cumulative.
Posted By: model70man Re: Crack in stock Q - 01/17/07
I drilled a 1/8" hole in the center of the crack on one rifle stock I had and used the 2-part epoxy made like a syringe, blocked the bottom of the hole I drilled, and then forced the epoxy until the crack was saturated, along with the hole. Worked for me. Thanks...Bill.
Posted By: DickD Re: Crack in stock Q - 01/17/07
Stocker, you a smart man who understands how things work. Wish everyone did. Dick D.
Posted By: macrabbit Re: Crack in stock Q - 01/17/07
The front screw hole has a touch of shininess on its front. That's the wrong side for what you're thinking, right?

How does one test seating of the lug? The face behind is quite smooth and black- I'd think that is a good indication.
Posted By: macrabbit Re: Crack in stock Q - 01/17/07
Is this what you mean, model70man, a plug of epoxy in this position?
How does that method sit with the others helping me?

[Linked Image]
Posted By: stocker Re: Crack in stock Q - 01/17/07
macrabbit: I would do a straight epoxy glue job initially so you can clamp the area and get it solidly back together. I would probably follow that up by cutting a trough from side to side ,through and well beyond the pink circle. You can actually extend it into the side walls of the stock a bit . The trough neds to be deep enough and wide enough to accept a section of about 1/8 Redi- rod and you can flare the ends of the trough so a mechanical lock also exists. Lay the Redi rod in a bed of glass bedding compound and then fill to level with glass aall the way across.

A mark on the front side of the screw hole won't matter except possibly for accuracy provided the hole is drilled square and the tightening of the screw is not walking the barreled action back and forth.

Try assembling the rifle while the whole thing is standing on the butt. When you slip the action into the stock you should try to feel for contact of the recoil lug against the stock. Place masking tape strips on the action and stock (separate pieces) with perfectly alligned fine index lines. As you tighten the screw do you see any deviation in their allignment? If there is you may find that when your screw is tight you have walked the action forward off the mortise a bit. Also check the screw for straightness as that can cause the same effect. If you don't want to do a full glass bedding job that reinforce should give you a lot of strength in that area.
Posted By: macrabbit Re: Crack in stock Q - 01/17/07
It's going to take me awhile to digest that post (I'm neither a woodworker nor a 'smith), so I'll be back later.

I appreciate all of this help, guys.
Posted By: Sitka deer Re: Crack in stock Q - 01/17/07
macrabbit
I agree completely with what DickD said. The crack means little in most situations. But it is exactly why I prefer the ADL style trigger guard. Having a continuous chunk of wood makes the action area of the stock stiffer and stronger.

I mostly agree with Stocker on his fix suggestions with a couple minor disagreements. I have never found metal rods to be worthwhile for fixes. Reinforced epoxy will fill a void and be plenty stout. His point about bending the ends to make a mechanical bond is exactly why I do not like them. They will "work" under temperature changes and break free of the epoxy. The bent ends will keep that from showing, but will not make it stronger. I have seen far too many of them fail to accept their use.

When I said the CA worked only because it was not needed I meant the stresses were not stout enough there to worry about. I would be inclined to skim a bit of wood off the top of that webbing and apply epoxy down in the crack. (work it open and closed and the epoxy will migrate down in there a bit.) Then I would lay a piece of fiberglass cloth on top and soak it with epoxy.

However there is one immediate concern and that is the cause of the crack. It may have been there almost from day one because the wood may have dried enough to allow the wood to shrink and crack. The fact the crack is standing open leads me to believe there is a good chance that is the fact. If it is, you will need to leave it open and reinforce as I suggested in this post.
art
Posted By: macrabbit Re: Crack in stock Q - 01/18/07
"leave it open" why? Because the wood's out-of-the-action state is open and natural, so don't clamp it closed and add that unnatural strain to the epoxied bond?

What sort of epoxy, or would any alert person be able to figure out at the store which types are unsuitable?

"reinforced epoxy"? Is that satisfied by the fiberglass cloth or do mean something else?


(I don't know from ADL or BDL, so you'all are losing me on stock styles. And remember, this is the pre-700 model 722.)
Posted By: Sitka deer Re: Crack in stock Q - 01/18/07
I lost track of the 722 part... The wood is not being stressed by the floorplate (thin stamped and bent metal in the 722) the way it would be in a 700 BDL which has some meat that sticks into the wood and is tightly fitted.

I assume the wood is not sressed when you put the action in???

The cloth will satisfy the need for reinforcement in the epoxy. I would not use any 5 or 10- minute epoxy. Get some that takes a bit longer to cure as it is significantly easier to work with and will be much stronger when cured.

ADL trigger guards end in front of the trigger... No metal under the magazine box.
art
Posted By: macrabbit Re: Crack in stock Q - 01/18/07
I've not yet done stocker's index line-screw tightening test (prob can't get to it today).

FYI, the trigger guard/floorplate and the under-trigger plate are fully and snugly inletted on this custom stock, although it's true that they are both just sheet metal.


Art, let's assume that this 'web' is touching or just clearing the bottom of the action. If I go with your method as stated, I'd have to relieve it to make room for the cloth/epoxy and then deal with release agents, etc. Is there an alternative?
Posted By: Sitka deer Re: Crack in stock Q - 01/18/07
Doubt you have to do it with the action in the stock... Make the repair and grind a little off to clear the action. Would probably heat the wood a bit to get the epoxy to wick in better, also.
art
Posted By: model70man Re: Crack in stock Q - 01/18/07
Yes Sir, I then squeezed the stock together from the sides after it had been completely saturated with the epoxy. Thanks...Bill.
Posted By: stocker Re: Crack in stock Q - 01/18/07
Sitka:I was not referring to bending the ends of the Redi -rod. I meant to open the wood on either side of the slot/trough across the web to create a dovetail on either side that extends slightly into the side walls of the stock. Kind of a double keyhole effect. It is a mechanical as well as an adhesive lock.
Posted By: macrabbit Re: Crack in stock Q - 01/18/07
I screwed action and stock together with three witness marks attached, noticed not the slightest change.
Lug seems to be well seated.

I've considered my capabilities; does this sound like a plan:

[Linked Image]

Dremel a trench across the web, somewhat into the sides of the stock. Include a little flare or 'dogbone'.
Heat the area a touch (with what, a hair dryer?), work epoxy into the crack as best I can and then fill the trench with epoxy also.
Include in the trench XX. (The thread has a yea/nay on redi-rod, and a top patch of fiberglass. The web shows shine, so I think it has contact with the action; I want to pass on the patch & grind. Art, any other suggestion for a 'micro re-bar', preferably something I might have on hand or available at the local hardware?)
Trowel even with surrounding surfaces.

To clamp or not to clamp?



The web is exactly 1 cm wide (L to R as pictured), barely more than that across. How wide and deep a trench?


((Please, nobody get sensitive that I don't follow a particular method exactly. I've got to synthesize with my own capabilities and tools in mind. Besides, it's consensus that this is not an emergency situation.))


PS, what is redi-rod? The threaded rod at the hardware store?
Posted By: stocker Re: Crack in stock Q - 01/18/07
That's what redi-rod (probably correctly Redi Bolt) is. I know Sitka doesn't like putting steel internally but it is simple and if he's seen it break free of the glass he's one up on me. For my own purposes for that type repair I use one of the super strong non strech fishing lines (currently Whiplash 30 lb test).
I have a little jig that has two adjustable dowels. Wrap the line around the dowels about 20 times and tie in the middle with fly tying thread to form a figure 8 of bundled line. 40 strands (both sides added together) @ 30 lb test is a lot of break strength. It is set in the cavity ( somewhat larger than your drawing ) and fill with glass bedding and you've done about all you can internally. There's a number of ways to do it. I clamp with moderate pressure after the slow curing epoxy has had some time to penetrate. I do go back and examine the stock carefully after the job is completed to relieve any new pressures that may show up in event that portion of the stock is now tighter than the rest along the upper inletting of the action.
Posted By: macrabbit Re: Crack in stock Q - 01/18/07
That's a cute 're-bar' system.
Posted By: Sitka deer Re: Crack in stock Q - 01/18/07
Stocker
That is a new one on me and I really like it! For once there is a use for superbraids! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

As an aside, epoxy does not require clamping for strength. If the wood is in the right place I would not clamp it.

Mac
Based on taste, presentation and originality I humbly cede to the good man to my SE! <img src="/ubbthreads/images/graemlins/wink.gif" alt="" /> I like his plan and intend to test it within the hour.
art
Posted By: 458 Lott Re: Crack in stock Q - 01/19/07
Art,

Do you have a stock to break first <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />
Posted By: Sitka deer Re: Crack in stock Q - 01/19/07
I have a couple stocks to repair where the concept will work and since I have your old '96 mouser to bed it would be a good time... <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />
Posted By: macrabbit Re: Crack in stock Q - 01/19/07
Do I have the green light?
Trench size?
Heat method?
Posted By: Pete_in_Idaho Re: Crack in stock Q - 01/19/07
A couple of years ago Stocker and I were engaged in a similar thread, He's a good craftsman and I told him if he ever needed a job he could come and work anytime in my cabinetshop <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />.

Twice I have repaired cracks just like this one and as far as I know they are still holding. I take a hacksaw blade and completely cut out the center web, maybe 3/8 -1/2in. wide, making it nice and square. Find and size a suitable piece of wood and using a burr in a Dremel grind holes about 1/16in. deep on all 4 sides, apply epoxy to all sides and clamp, (I wouldd use a small handscrew clamp), finished! Just make sure the block is a close fit to the opening. Pedro
Posted By: stocker Re: Crack in stock Q - 01/19/07
Hello Pete: Didn't know you frequented this forum. Still happily retired and doing stock work when it occurs or I am inclined. I'm just finishing a piece of myrtle wood that I did from a 3" blank to fit a friends Browning A-bolt. Terrible rifle to inlet with it's semi-clip and lack of draft on a lot of the metal. But the grain would knock you out of your socks. Fiddle back, mini-quilt and bits of burl all in the same piece. Full length figure, both sides. It also had a couple of small bark inclusions which were removed and filled but the join is in areas that are barely visible and I was able to match the grain perfectly. Also found a 22 bullet in the wood I removed for the magazine so no harm there, but I'm glad the guy wasn't shooting an automatic at a target on the tree. Maybe he shot a squirrel.

Hope all is well with you.
Posted By: stocker Re: Crack in stock Q - 01/19/07
MacRabbit: I would make the trench wider than you have pictured and extend it further into the sides so the reinforce has plenty of support behind it beyond the trigger mortise. Deep as you like but don't come all the way through. About 2/3rds of the way seems about right. I usually don't bother heating the wood for this repair as there is also a generous shot of glass bedding compound going in the trench, although it may help absorption of the epoxy into the wood. For a small area a hair dryer would probably suffice to warm it. I think you can decide this one.
Posted By: macrabbit Re: Crack in stock Q - 01/27/07
For better or worse, the deed has been done. I'll know more in 8 hours or so.
Posted By: macrabbit Re: Crack in stock Q - 01/28/07
Thank you all for your help. We spent more time typing than I did performing the fix but the thread taught me a few things.

I'll check the stock in another 30 years and let you know how it held up.
Posted By: macrabbit Re: Crack in stock Q - 01/29/07
Gee, my 'smith had that rifle inletted to a T! I thought my epoxy was flush but discovered that there was no longer clearance for the bolt stop lever to drop enough to allow removal. A little knife work and it's done.
Posted By: stocker Re: Crack in stock Q - 01/31/07
macrabbit: Just back from Reno and checked to see if you'd done the deed. Glad to hear you forged ahead.
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