doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Sidelock Gap or No Gap

1893 L.C. Smith Farm Implement Pigeon Gun; post 125 years of wood shrinkage and use



1902 A2 Variation 2



It is my opinion that the (1886) design defect leading to cracks at the apex of Smith sideplates is here; inadequate wood at the head of the stock with cracks extending toward the butt. The rotary bolt, the top lever spindle, the safety and the cocking cams all require removal of wood, and the width of the vertical channel for the spindle is usually larger than necessary.



http://www.picturetrail.com/sfx/album/view/17090409

For comparison; a Baker Batavia Special



Baker Paragon



Early Baker B grade



More examples
http://www.picturetrail.com/sfx/album/view/15127852

Purdey courtesy of C.J. Opacak - wow



Obviously a large gap around the lock IS a potential problem, but it is interesting how few utility grade Crescents are cracked

The high end non-farm implement English sidelock guns I�ve seen have no gaps. The locks and wood are even beveled for a perfectly tight fit, I think to keep H2O out of the lock mechanisms.

You were just ahead of me Bro. Buzz

McIntosh suggested that part of the "Long Cracked Smith" problem was because the sideplate was not beveled. Click on the 5th page
https://books.google.com/books?id=lIR7Aw...ith&f=false

Smith, Baker, Aubrey & Crescent were not; nor were Tobin's

Here's a pic of the head of the stock on a Parker AA hammer gun. I have it for some conservative restoration. It's 120 years old or close to it.

Doug

When a sidelock, or side plate, is solidly mated to the action it becomes a possible part of the recoil force against the wood, just like the rear of the action that is bedded/inletted into the head of the stock. No wedge shaped part, be it the rear of the lockplate or the rear end of a tang, should be a recoil bearing surface. If the stocker does a good enough job of inletting the action into the head of the stock, this is where the bulk of the recoil bearing surface should be. If it does not make good enough contact with the head of the stock there will be movement of the action, and any associated parts (lockplates, tangs). If that occurs, the tangs and the rear of the lock plates will be forced against their associated wood inlets. When that occurs the wood will either be compressed or it will split at those places.

Put another way, if the inletting of the lock plates and tangs are tighter than that of the head of the stock, and the gun is shot enough, there will eventually be hell to pay, in the form of cracks.

Again, JMHO. SRH

Think about the beveled lockplate edge suggestion for a minute. The edges are beveled to facilitate better/easier inletting...........to make the wood appear as if it grew around the metal. The two locks are solidly fastened together with a screw, and are solidly mated to the action. How could a beveled edge prevent cracking? It doesn't have the ability to slip against the wood under recoil, because it is so tightly bound to the lockplate on the other side.

McIntosh notwithstanding, I believe the problem with L C Smiths cracking behind the lock plates and tangs is not because the plates are not beveled, rather because there is so little surface area at the head of the stock to absorb the recoil of the action against it that it compresses much too easily. Then, all other closely inlet metal to wood surfaces become recoil bearing surfaces.

I would welcome the correction of a professional stockmaker if I am wrong in this regard. Because, if I am wrong I want to be right in my understanding of the forces at play.

SRH

The LC issue is pointed out well above. I think another factor is the type of wood. English seemed to fair better than Black. But work quality and frame size may have also played a role at the same transition point.

I have some pre 13's w/really nice contact inside. On the other hand, I just messed around w/a 1940's 16 gauge you could see light through the head of action. Not one point of contact. Stocks is in perfect shape otherwise. But, it wouldn't have been for long. The company was clearly just hanging on by then...

Flawed as they are I love them.

Stan and Phunter ,good points by both of you and in my opinion as someone who does this for a living its exactly the issue ...I just built a custom for my son last christmas on a lightweight 20 frame ...the original inletting was apparently accomplished by quite a small beaver with ADS ...so it wasn't hard to improve there,I also used a piece of real nice Canadian grown black walnut ,like I said pretty, but as some of you know most black walnut is not hard as it it could be ...after inletting I sealed the head with wood petrifier ,Ill see how that helps

Readings on longitudinal shrinkage.
http://www.wood-database.com/wood-articles/dimensional-shrinkage/

I read some years back it was not at all uncommon to find original "Pennsylvania" Long Rifles with the forearm of the stock pulled apart.
This would have been the result of "Longitudinal" Shrinkage. These guns had their breech plug tang screwed to the stock & the forearm pinned tightly at several points along their length. The wood shrinkage over the years literally Tore them apart.
























































































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