Fixing pin blowouts

[Texas Gil]

I have a blowout after inserting a pin backwards. What’s a good repair as stock has been refinished in dark red stain and true oil completely seasoned?
Driving me nuts!

 

[ArmorerRoy]

Hopefully you didn’t lose the pieces. A non period correct fix is to carefully glue them back in and clean up the hole with a needle file or drill.

 

[deerstalkert]

pictures will help. a painting will suffice if'n you don't have a camera

 

[Comfortably_Numb]

I have never had a gun apart that made any difference on which way the pins went in.

 

[HSmithTX]

Like Mike, I make sure the pins can go either way. Fix the holes and fix the pins while you have it apart.

 

[user 34300]

The ends of the pins need to be tapered a little. Cut them so they fit below flush with the wood. That way you can use the hole to center you punch. If the pins are flush or above the wood you will trash the wood with the punch when you miss. A little bee's wax will keep them from rusting and seizing in the hole.

 

[Comfortably_Numb]

Also, make sure the pin isn't bent and make sure the lug is slotted

 

[IanH]

I have never had a gun apart that made any difference on which way the pins went in.

You have now.

As was said, taper BOTH ends if the pin so it will go in/out/through any which way without blowing the edges of the holes, especially when the wood swells from moisture or oil after installation.

 

[sturmkatze]

Also, make sure the pin isn't bent and make sure the lug is slotted

How long should the slots be?

 

[Comfortably_Numb]

You have now.

As was said, taper BOTH ends if the pin so it will go in/out/through any which way without blowing the edges of the holes, especially when the wood swells from moisture or oil after installation.

Huh? Did I just take a gun apart and not realize it? the damage described above is caused by bent pins.
I know of several modern builders that make pins go one way only, but I don't see what advantage that is. Never seen it on an old gun. I have an old NE fowling gun that has pins in blind holes, they go in one side and don't come out the other. It's permanently assembled.

How long should the slots be?

Just long enough so the pin won't bind when the stock swells and contracts. Probably 3X the width of the pin would be plenty.

 

[deerstalkert]

while inserting pins i try to run my pin stock through while spinning with a drill. making certain the end is rounded and polished. run it through then draw it back until the off side is 3 times the diameter below the wood. bull nosed cutters snip and touch up with a fine file. drive back in and both sides are below the wood. bees wax over the hole so they won't rust and go shoot!

 

[Col. Batguano]

How long should the slots be?

That's a function of the direction of the wood grain in your stock, and its' offset angle from the barrel direction. I have a 48" barreled gun on a highly curled stock that moves .100" over the course of a year. The straighter the grain, the less the movement.

The slot for the pin closest to the breech can be shorter than the one nearest the muzzle. The bolts through the stock (both tang and lock bolts) will serve to anchor the stock to the barrel from that area. Call that spot "ground zero". The slots are there mostly to accommodate seasonal wood movement. The length of the slot(s) needed is largely a function of the grain of wood in your stock.. Maple will move about 1/4" tangentially, and 1/8" radially per 12".

You have a few options here;
1.) Mark the stock at the pin locations and measure the movement with a micrometer over the course of a year and elongate your slots accordingly
2.) Measure all the oblique angles of the stock grain and calculate the stock movement with trigonometry at the various locations based on the current season
3.) File them about 1/16" (I'd go about half of that in both directions) and check them periodically throughout the year to see if they are getting at all tight or overly difficult extract or to reinsert. Adjust as appropriate.

I would personally opt for a variation of option 3 myself. While math and calculations are fun to do, they're unnecessary in this instance. Just remember it's the RR side of the pin hole in the lug that provides the holding power for the stock to the barrel... If you're going to err at all in enlarging the hole, do it on the barrel side.

The way I've done it in the past is to take my (power hand) drill and put it in the tab pin hole. Then, with the drill running, I just tip the drill in both directions (tipping parallel to the bore direction) to create something of a "ramped" hole fore and aft. Then, I'll bring the drill back to vertical, and use the edge of the bit as something of a milling bit to elongate it in the middle. That helps to keep me from hogging out the RR side of the hole.

And oh yeah, check the edges of your pins for burrs. Stone them off. That's usually the cause of most tear-outs.

 

[Comfortably_Numb]

Nifty. I cut my slots with a jewelers saw. I have never actually measured them. I don't think you can cut them to wide.