I have heard this before

[Dennis Glazener]

if the tang and trigger plate are screwed together thru the wrist, it will make a 'monolithic' unit......it'll be somewhat stronger

marc n tomtom

I am not trying to pick on kaintuck, just would like some engineer or other structural design person to settle this in my mind. I have built rifles with through bolts and with a single wood screw on the tang. Which way is the stronger design? It just doesn't seem that a hole all the way through a wrist can be any stronger than one using a shorter wood screw. I have heard the through bolt sandwiches the wood between the trigger plate and the tang but the wood also looses strength with the hole drilled for the through bolt. I would think that a force coming from either side, everything else being the same, the stock with the through bolt would snap easier.

I suspect either way is fine until you start falling around and banging the rifle in this area.
Dennis

[WadePatton]

I'm no structural engineer, but i do believe that the "full" tang (i don't consider it "extended" until it goes OTC) found on most TN and many Southern guns _is_ a functional item.  And my engineerish tendencies cause me to think a simple screw(s) is adequate, that removing more wood isn't beneficial.

So much is dependent upon the grain and density and soundness of the wood in that area.  I have a blank of walnut on hand with a bit of runout in the forend.  I would _not_ build with that wood were the same runout in the wrist.  I do hope that the bbl (and the dowel used for support when bbl is out) will afford enough strength to avoid having to fix a break. 

[Robby]

Seems to me that if you have grain runout to the degree of that stock that was posted recently, if it fell, it the moment of impact the metal would flex enough to allow the wood to crack. I either system that Dennis describes would strengthen it somewhat but I don't believe it would prevent the wood from breaking if the grain isn't right, with even a moderate blow. I believe with good fit the thru bolt would be stronger, much the way that any laminated piece of wood is stronger.
Robin

[JDK]

I agree Robby....you just beat me to it.

IIRC this very subject was discussed here some years ago.....probably in the "old forum".  The consensus was then that such reinforcement was no substitute for grain runout in the wrist.  If anything, it only strengthens what natural characteristics a wrist with proper grain structure already has.....again, big IF.

Engineering, being a science, and wood being unpredictable, if engineers designed longrifles I'm afraid they would have the 4" diameter wrist that Mike Brooks alluded to.

Enjoy, J.D.

[Daryl]

I cannot see a simple wood screw producing the same wrist strength as a through bolt. There must be a reason for what appears to be ALL the better made guns having through bolts, tying the trigger plate to the tang with a through screw or bolt.

 Cheaply made guns such as in those of the mass production market of the 70's, etc, made copious use of wood screws to holding the trigger plate and guard to the stock, and tang to the wrist. Why would the "Better Made Firearms" all have through bolts, many of the later ones having 2 tang screws. If wood screws were just as strong, all guns even modern ones would have wood screws holding everything together- seems to me.

This may be a simplistic way of looking at it, but with quality firearms, you usually get the highest quality & that appears to mean through screws. Is this a coincidence? I don't think so.

Both Taylor and I had to get replacement stocks for our TC's because they fell over - once each - and the stock broke through the wrist.  They had wood screws holding the tang down.  All of my current rifles, except for the Musketoon have fallen over at one time or another - yeah, I'm clumsy & careless sometimes, yet none have broken through the wrist - interesting - through screws from Tang to trigger plate. I'd say from this, that through bolts were X times stronger then simple wood screws. Just a rough guess on what minor experience I've had with both systems.

In fact, my buddy Keith's Purdey style .75 that Taylor built back in about 1987, fell over as it was leaning against his pickup  truck.  His Dad drove forward, the turned around to head to town. The rifle fell down as he pulled ahead and when he backed up, he backed over it the wrist with the rear tire when turning around, incrdibly, the stock did not break and only received a few scratches is all. I do not suggest this as a test.  It had a through bolt from tang to the trigger plate.  I wonder if that helped or made it weaker? Well, you know where my vote goes.

[WadePatton]

Daryl, you know i agree with you on most points, but I'm thinking more about the somewhat better wood used by us and the old-timers, and how seldom i see through-bolts on TN guns.  Not the often horrible and lightweight "wood" of modern productions of which you speak (in part).  I have a through-bolted two-piece walnut stock that is broken, but that's all i can say about that as it's a lever thing.

If i break a longrifle wrist, i'll through-bolt it on repair mebbe for sure.  

[JDK]

No argument from me that the best way to fix the tang is the traditional through-bolt to the trigger plate.

What I thought we were talking about here was long tangs ala SMR's and Hawkens' with a couple or more bolts going through the wrist.

Enjoy, J.D.

[Mark Elliott]

I DO have formal training in statics and dynamics, and it is my opinion that a through tang bolt is only an advantage when it attaches to a long trigger plate that is screwed to the stock at the other end.   Otherwise,  it just removes more wood that weakens the lock mortice area and wrist.   Additionally,  with regard to the over the comb tang, it will not keep anything from breaking.  It will just hold the two parts together for a while (maybe) after the break.  

Over the comb tangs are pretty flimsy things,  That is one of the things that makes them so difficult to inlet.   I have to be very careful not to break the the things off when removing the barrel.    The skill involved in building  a gun with an over the comb tang is not forging it.   That is really pretty easy.  It is inletting it that is the pain in the rear.    

My opinion is that the multiple screws in over the comb tangs and long set trigger plates just compensate for all the wood removed to inlet them.  I don't believe they result in a stronger stock.   Like everybody else said, it is more important for the grain to run through the wrist, and to leave as much wood as possible in the lock mortice and wrist.  Also,  don't leave sharp corners in inlets as a place for cracks to start.  

Most of the old guns I have repaired/restored seem to have mostly self destructed due to poor grain orientation, inlets that are too tight,  and wood shrinkage over time.   Do not underestimate the problem posed by inlets that are to tights.   While my past work wouldn't be a good example of this, I have come to the conclusion that mounts should go into place without force; allowing just a few thousandths of an inch clearance.  

 

[Mark Elliott]

I may have missed the argument that somehow a through bolt in an of itself stronger somehow.   The only thing a through bolt does on its own is to hold the barrel in the stock.  That is the same think a wood screw does.  As I have never seen a wood screw in barrel tang pull out,  I can't see a through bolt as a real advantange.  It is certainly a theoretical advantage, but I have seen no evidence that it is an actual advantage in any way.   It is just convention with a lot of styles..   

[Dennis Glazener]

Engineering, being a science, and wood being unpredictable, if engineers designed longrifles I'm afraid they would have the 4" diameter wrist that Mike Brooks alluded to.

I am asking about inherent design using identical tangs/triggerplates/wood etc  on each design. Just asking about the strength of each design through the wrist area.

Dennis

[Mark Elliott]

Engineering, being a science, and wood being unpredictable, if engineers designed longrifles I'm afraid they would have the 4" diameter wrist that Mike Brooks alluded to.

I am asking about inherent design using identical tangs/triggerplates/wood etc  on each design. Just asking about the strength of each design through the wrist area.

Dennis

If all other things are equal,  I have seen or learned nothing that would lead me to believe there a significant difference between a through bolt and a wood screw to secure the barrel tang.    Is that short and sweet enough. 

[T*O*F]

If all other things are equal,  I have seen or learned nothing that would lead me to believe there a significant difference between a through bolt and a wood screw to secure the barrel tang.

When Matt Avance bought TVM from Jack Garner, the first change he made was to use tang bolts instead of wood screws.  Jack believed as you do, but Matt had had his fill of having to repair or restock guns that failed because of the wood screws.  These problems show up when thousands of guns are being built and used, not when one just builds a few guns.

On the other hand, English guns are about as slim as one can get, and they are double cross bolted.  Even so, you see hundreds of original English doubles with cracks down thru the wrist.  The cracks always originate at the lock bolt and travel backwards.  You seldom see the wrists themselves being broken unless they are hit with some lateral force from the side.

[David R. Pennington]

I'm no expert as engineer or gun builder but my 2 cents would lean toward through bolt not for adding strength but for durability. If the barrel is removed several times, eventually removing and replacing the wood screw would eventually "wear out" the threads in the wood. The through bolt could be removed and replaced hundreds of times before the steel threads in the trigger pate would wear out. But f it is a TN with over the comb you aren't going to pull the barrel unless you have to. I know this doesn't answer the original question but is something else to consider.

[Ric27]

I'm no expert as engineer or gun builder but my 2 cents would lean toward through bolt not for adding strength but for durability. If the barrel is removed several times, eventually removing and replacing the wood screw would eventually "wear out" the threads in the wood. The through bolt could be removed and replaced hundreds of times before the steel threads in the trigger pate would wear out. But f it is a TN with over the comb you aren't going to pull the barrel unless you have to. I know this doesn't answer the original question but is something else to consider.

While it is true that a bolt is going to hold up to multiple removals better than a wood screw there really is no reason to remove the barrel out of a gun once it is completed. That is unless something breaks or you need to move the rear sight forward so you can sight through it again because you eyes are like mine, old.

I always thought that the tang bolt was a structural component but i will have to go along with the wood is king camp. I have seen a heavy wristed Rev War era gun pop at to wrist with very little pressure because the grain played out on top of the wrist. That big old tang bolt was still in place while the gun lay on the ground it two pieces.

[Marcruger]

Hi Dennis,

I have pondered in the past a hidden and decidedly non-traditional idea for strengthening the wrist area.  Not sure if it would work, but I thought it was worth mentioning.  I am an engineer, but a civil not mechanical one, so take this idea for what it is worth. 

In the case of a vertical through bolt from tang to trigger plate, wouldn't a tubing sleeve epoxied in place strengthen the wrist wood?  Most wrists I see broken are a shear break in the horizontal plane along grain lines. 

I am thinking of a metal tube, inside diameter matching external diameter of the bolt.  The drilled hole in the wood of the wrist would match the outside diameter of the tube (or just slightly bigger).  The tube would be slightly shorter than the depth of the hole to allow for slight compression and wood shrinkage.  The tube would be epoxied in place, and would be invisible with the gun assembled. 

In the past I have read that wood, glued with modern glues, rarely ever breaks at the glue joint.  Therefore, I'd think it would prevent or reduce the chance of shear breakage through the wrist. 

Any thoughts folks? 

On another note, a gentleman I know who builds longrifles shared with me that he soaks thin super-glue into the internal inletting of rifles he builds, especially in thin areas.  He told me that he hasn't had one crack yet. 

Again, though not traditional, it seems an interesting "insurance policy".  Thoughts on this idea?

Best wishes, and God Bless,     Marc

[Mark Elliott]

If all other things are equal,  I have seen or learned nothing that would lead me to believe there a significant difference between a through bolt and a wood screw to secure the barrel tang.

When Matt Avance bought TVM from Jack Garner, the first change he made was to use tang bolts instead of wood screws.  Jack believed as you do, but Matt had had his fill of having to repair or restock guns that failed because of the wood screws.  These problems show up when thousands of guns are being built and used, not when one just builds a few guns.

I can see how in the hands of the masses,  a through bolt could be less trouble.     I am basing my opinion on a relatively low number of guns handled as compared to what TVM has probably produced.   I only use a wood screw in the tang on SW. VA and E. TN iron mounted guns.   Everything else uses the through bolt.    Where I do use a wood screw,  it is a big one; at least 3/16" in diameter and 1 1/4" long (the same screw I put in the heel of a butt piece).  

I don't plan on changing MY practice, though.    I doubt that I will ever build enough rifles with wood screws in the tang to see a problem worth addressing.  

[Captchee]

 I cant really say what is strong if all things are equal.
 I wonder though if we cannot take a lesson from other types of construction where holes are drilled through  structural components like wall studs , floor joice or truss.
 Thus it may be really more of half of one and a dozen of the other  as  long as it’s a hole  that does not end up being a notch  there maybe no real structural difference

 While I have seen many a fine double with a broken wrist . IMO this is more do to the lack of wood in the wrist   do to the locks  on each side . Not so much the tang bolt . I also feel that more times then not the stock were broken  either during loading or by being dropped  or  when they have fallen over on a hard surface. There just isn’t a lot of wood in a SXS wrist   

[Cory Joe Stewart]

This is something that I worry about a lot.  I have a slender southern mountain building coming up and consider doing a through bolt to the trigger plate to add strength.  But then after thinking about it, by the time you inlet the tang, inlet the lock, inlet the set triggers and the trigger guard, you have removed so much wood from that one critical area.  A bolt would only remove more. 

I think I worry more because my first rifle did crack in that area after very little shooting.  It was not dropped.  The problem was everything was too tight.  Which at the time I thought was a good thing.  But as Mark has noted, too tight can cause problems. 

I guess the lesson is that there is no one thing that can cause the issue.  A through bolt can't save poor grain orientation.  Or rookie mistakes.

Coryjoe

[frogwalking]

I am an engineer, and while I practiced as a civil type, when I went to school and took the professional engineering test, civil and structural were not differentiated.   I recently made a Tennessee type rifle, and through bolted the wrist, near the barrel, and close to the comb.  I have no test results or calculations to prove it, but it seems intuitive to me that such construction would be stronger than wood screws that did not make a direct connection between the top and bottom steel straps.  I visualize it as a sort of hillbilly I beam that has the steel straps acting as the flanges and the wood wrist serving as the  web.  as I said, this is only my opinion, and I have done no research to prove anything. 

Someone said that wood can't be considered  structural material since every piece is different, or something like that.  I have a wood structural construction manual somewhere in the shop.  Every time a roof truss is made from wood, somewhere in its history is the original calculation to decide what size member to use, where to place it, and how to attach it.  For load considerations one starts with a theoretical strength value, then apply various percentage factors to take the quality of the wood actually used, as well as the importance of the structure if it fails.   I don't know how this would apply to longrifles, but the theory is still  valid.  I have seen a number of original rifles with broken wrists where the grain in this area was terrible.  I can only surmise that the old time gunsmith used nearly every piece of wood that came into his hand to make a rifle.  I have seen some originals with such bad grain direction, I would not have used the stock blank.  But then, I don't need to feed my family building guns (Thank God.)

[WadePatton]

Yes, we used centuries old engineering practices to size the beams and posts of this timberframe construction.  Never mind the pissy little 2x4's-they are just filler.  The poplar beams and posts are interlocked by mortise and tenon with wooden pegs-no metal.  No metal at all in the main structure.

But that's too chunky for a rifle.  

...
Someone said that wood can't be considered  structural material since every piece is different, or something like that.  I have a wood structural construction manual somewhere in the shop.  Every time a roof truss is made from wood, somewhere in its history is the original calculation to decide what size member to use, where to place it, and how to attach it.  For load considerations one starts with a theoretical strength value, then apply various percentage factors to take the quality of the wood actually used...)

[Pete G.]

I guess it all boils down to what you consider "strength". Removing wood from top to bottom with a clearance hole interrupts grain strength in an area that has already had most of the wood removed. Whether the clamping strength added by a through bolt is enough to compensate for this loss is open to debate.

I do know that if you peruse the Kindig and Shumway books you will find numerous examples of through bolted guns with a repaired broken wrist.

[Pete G.]

Yes, we used centuries old engineering practices to size the beams and posts of this timberframe construction.  Never mind the pissy little 2x4's-they are just filler.  The poplar beams and posts are interlocked by mortise and tenon with wooden pegs-no metal.  No metal at all in the main structure.

But that's too chunky for a rifle.  

A Chunk Gun perhaps ?? 

[davebozell]

Like frogwalking, I am an engineer.  In general, laminations are going to be stronger than a single material.  Where I struggle, is seeing a real lamination along the trigger side of a long rifle.  There may be sections that would have laminate properties, but unless there was continuous metal running from under the barrel to the back of the tang, it's not really a continuous lamination.

One other thing to consider is that a wood screw is really just a circular wedge....

[kaintuck]

Wade, you should see some of the post n beam Amish barns.....they can bear tons of hay in the loft...for decades!.....if I was younger, I would love to build a house with pot n beam ceilings, I always thought they were cool.......

But everyone.....think about a brick wall......all those bricks are not the strength until they are joined together with compression by the weight, and no flex.......I believe all the fibers can move in a small wrist...flex....but slightly compress that with a couple on bolts from/to metal plates......you will have a a more stable design......

I'm not a engineer.....but I have built a WORLD of RC airplanes......and you learn some funky tricks to keep things strong and light.......

Besides.....tomtom said it was so........!
Marc n tomtom

[Dan'l 1946]

  I think the real issue is grain run out in the wrist. "Musket grain" through this area has probably accounted for more broken wrists than any screw or bolt hole. While I've never broken a stock through the wrist, I've seen several and they all let go due to poor grain in the wrist.
                                                                     Dan