Wood Movement And Tenons

[Erzulis boat]

I was discussing wood movement due to climactic changes in another thread.

On my Trans rifle, I am running 3 barrel tenons with .078 diameter pins, and also have incorporated a .129 diameter crossbolt for a front sling swivel.

The barrel remains pinned overnight sometimes, is worked on at odd hours (morning/ evening/ all day) and I have yet to experience any movement. I do live in California, so wood movement is not really an issue (coastal, southern).

The pins line up everytime, the rifle is by an open window in the shop, and of course it has no finish whatsoever.

It would be interesting to hear some stories about what changes and movement have ensued, and how this is dealt with.

Also, to what degree was this halted by the sealer/finish.

Has anyone actually had a forend crack because no slot or allocation was designed into the tenon?

I do travel with my rifles, so this is now an issue at the forefront. I go to Alaska, Florida, Texas, Kentucky etc. so after The Fatdutchman posted his experience with a full 1/16" of movement, I now have to find some answers.

These full length (and long!) forends have altered my gunbuilding for sure.

 

[bioprof]

I have an antique Ohio rifle that has cracks at the pins for the barrel tenons. I haven't taken it apart though to see if they slotted the holes to make room for movement during recoil. It looks like that might be a problem though.

 

[Mike Brooks]

I have seen forends lengthen more than 1/8". barrel lugs must be slotted length wise to allow for travel. I have seen pins bent in U shapes when the lugs are not slotted. Also tends to make your shots string vertically when your barrel heats up.
If a customer HAS to have a sling swivel mounted I usually tell them fine, just take the damned thing out when your gun won't shoot accurately anymore. :winking:
Guns built in your area of the world and end up living in my part of the worls tend to "grow" quite a bit. The same only opposite for guns made in Florida or somehwere similar and sent out west. They shrink so bad their boxes won't close any more and their inlays pop out.

 

[Erzulis boat]

Boy, am I glad that I posted this one. :shocked2:

I will slot my tenons and not look back.

"Gunbuilding 101" has inspired me to have 100% wood to metal, with no epoxy or Acraglas whatsoever, so this must really apply now.

If a sapling can lift a sidewalk................

 

[54JNoll]

I leave space for movement between the barrel tennon and the stock and then slot the tennon. Both wood and pin are free to move fore and after with respect to the tennon but are fixed to each other. It is not hard and is just good insurance.

 

[Stophel]

Good point...make sure you have room in front and back of the tenon in the inlet for the tenon to slide back and forth.

I used to think that there was absolutely no reason whatsoever to slot the tenons...wood can't expand or contract over it's length. Well, it can't, BUT, when the wood is curly you have LOTS of cross grain stacked up over the length of the fore end.... Slotting tenons is an absolute pain in the @22, but it is worth doing.

 

[Mike Brooks]

Slotting tennons is easy, stay tuned for more Gunbuilding 101. :thumbsup:

 

[Harley Donaldson]

I have an original fullstock where the foreend is broken in three pieces. The breaks are between the pins. From what I can see the tenons were never slotted. The history on this rifle was that it was stored in an attic for years and years and when it was found it was broken. the rifle appears to to a penn. factory rifle. Well enough made but nothing fancy. Nothing has been done to this rifle as I thought that sometime in the future someone would like to find an old gun that hadn't been fooled with.

 

[LRB]

At the Alafia Rendevous, I saw a fowler that the entire section of the stock forward of the front pin had just poped off. The pin was still in the unslotted hole and was bent to a U shape.

 

[BLAHMAN]

I slot the tennons also. I also slather in a liberal amount of beeswax from a tiolet bowl ring (new)in the barrel channel upon finishing the project.

I use a small needle file.

 

[Erzulis boat]

Well, I slotted my tenons this weekend, and contrary to my fears, everything stayed nice and snug in the stock.

I took an "on size" drillbit, chucked it into the dremel, custom turned a small cylinder (acetal plastic) that held my distance from the underside of the lug, and the flutes on the sides of the drillbit created a slot (left and right) in the steel (alloy 1144) in about 2 seconds. The bit was new, so the flutes were still sharp.

Worked perfectly.

Thanks, Fellas.

I ran into a guy at the SBMA Benefit, that is a World renowned wooden article preservationist for the big museums around the globe, and I ran the "Tenon Riddle" by him, and his reaction was EXTREMELY interesting. He specializes in furniture and structures, but he has knowledge of antique arms also. Another post, another time.

:thumbsup:

 

[Birddog6]

I have always slotted my pin holes in the tennon, simply because I was told it was necessary.

I have taken apart several used rifles that the pins were bent & when I went back to put the pins back in the holes, they didn't line up, 1/2 hole off or whatever, instilling in me that it IS necessary to elongate the holes fore & aft.

I used to use a solid tennon & drill the hole & then drill one before it & after it & file them to one slot. Now I usually just use a slotted tennon....... It is exactly the same small milled tennon but has the slot already cut in it. Drill the hole into the slot, take a needle file & open it up a lil fore & aft & it is done....... The slotted one cost ? .50 more but you break one drill bit & you paid the dif. of the slotted ones.

 

[Vaino]

I make the lugs out of sheet brass and after drilling for a 1/16" dia. pin, use a Dremel w/ a small cutter to elongate . The barrel side of the slot can have "slop" seeing the other side of the slot pulls the barrel and stock together.