slotting barrel lugs

[Natureboy]

  I've read in this section, and also on the Colerain website, that the pin holes in barrel lugs should be cut to make slots, allowing the barrel and wood to expand/contract.  My question is:  which end should I cut--fore or aft?

[Dennis Glazener]

Both if I understand your question. The slot for the pin should run a little bit forward and a little bit aft of the cross pin. You need enough to allow for expansion/contraction.
Dennis

[Natureboy]

  Thanks!  I assume I can use a jeweler's file.

[Mike Brooks]

  Thanks!  I assume I can use a jeweler's file.

Jewler's saw would work better.

[Mark Elliott]

I drill the pin hole,  expand it at least 1/16" in each direction with a jewelers saw,  and then clean up the slot with needle files.   You should let the season/humitity guide the length of the slot in front and behind the pin hole you drill.   If Summer, you just need a tad of space in front of the pin and at least 1/8" behind.    You reverse that for the Winter.   In the Spring and Fall, you can make the length front and back, about the same.   The muzzle of a rifle can move 1/8" over the course of a year in a place with four distinct seasons.  

[heinz]

Look up longitudinal shrinkage in maple on the web.  It is  generally accepted as less than 0.1%; less than 1/8 inch for 100 inches and that is for green wood to kiln dry. Radial and tangential shrinkage (across the grain) is almost 9 inches tangentially  and over  4 inches radially under the same conditions in 100 inches 
The shrinkage due seasonal changes from moisture is more like 1% across the grain and .05% along the grain. If we are not concerned about the barrel and lock not being inlet to tightly across the grain ( mine never are😊) we need not worry too much about the barrel pin clearance.  A little bit of longitudinal pin clearance is an appropriate caution, a few strokes with a needle file will do. Rember the barrel will lengthen a bit as it heats up at the range.

[Mike Brooks]

Interesting. I can usually turn a blank into a finished gun in about 3 weeks....depending of course. Many times  the wood expands or shrinks massively in that time and will bend pins alot if the lugs aren't slotted soon . I usually cut the slots after I get the tang screw in. In fact, if I don't the pins can be difficult to remove and IMPOSSIBLE to reinstall and will blow out the wood on the "out side" of the stock when driven out. I'm using good Kiln dried wood, usually from Dunlap who dries wood properly. Maybe the fact that I'm building guns in a non climate controlled area where the humidity can be 80% in the summer.

[Turtle]

  When I have the barrel out after drilling the pin holes, I rock the drill bit straight fore and aft in the pin hole. Then I needle file the sharp edge left in the front and back of the hole.
                                                        Turtle

[heinz]

Mike, i did not say the forearm would not warp and bind from shrinkage, it is just not longitudinal shrinkage. The bench rest shooter who taught me how to build rifles showed me by removinf the barrel for a couple of days and the putting it back in and tightening only the tang screw without putting in the pins. I think you will find the barrel is stabilizing the forearm, keeping it from warping.

[Mike Brooks]

Mike, i did not say the forearm would not warp and bind from shrinkage, it is just not longitudinal shrinkage. The bench rest shooter who taught me how to build rifles showed me by removinf the barrel for a couple of days and the putting it back in and tightening only the tang screw without putting in the pins. I think you will find the barrel is stabilizing the forearm, keeping it from warping.

Longitudinal shrinkage is the only problem I have....bent pins, no warp or bind. The length of the forestock either shrinks or extends. Could just be the climate where I live as I don't have a climate controlled shop. Winter gives me 20% humidity (wood burning stove) and summer gives me 80% (no air conditioning). I don't have this problem with something like a Chambers kit as the wood adjusts to the climate in my shop before I start on it. Working from a stock blank is what creates the largest problem as the wood is thick and can't adjust to the humidity at the time of the build. It really isn't much of a problem as long as I remember to slot the lugs as soon as I place the tang bolt. The barrel is never out of the gun when I build except for maybe an hour when I shape the top of the forestock.
 Excessively curly wood seems to grow longitudinally more than non curly.

[Natureboy]

   My $7 solution:  I went to a local hardware store to look at jeweler's saws, and thought that the blades were too thin to allow for the pin to slide in the lug.  And the handles were $21, the blades another bunch of bucks.  So I bought a carbide burr for $7, and used that by pushing it sideways
in the hole, elongating it fore and aft.  That should allow for any movement due to the barrel heating up or the change in seasons.  In Oregon, we have two seasons--Rainy and August.

[Mark Elliott]

I have had pretty much the same experience as Mike with expansion and shrinkage due to humidity.   In my current shop,  I use heat, air conditioning, humidifiers, and dehumidifiers to keep the humidity around 50-60% year round.   That way, there is little movement in the wood while I am building the gun.  

However,  once the gun leaves the shop and goes in the house,   I get noticeable shrinkage and swelling in ALL directions due to seasonal changes.  
When I worked in unconditioned space, the changes in the stock while I was working on it where just as Mike described.   In the summer,   I could be inletting a barrel that was going in and dropping out just fine.   A thunder storm could roll through (generally only 15 minutes and they are gone ), and at the end of it,  the barrel COULD NOT be removed from the stock until it dried out.  It would be like I super glued it in.  By the way shrinkage in low humidity is MUCH slower than swelling due to high humidity.   This is my actual experience.  

Also,  kiln dried wood is much more prone to movement than air dried wood.   The longer a stock blank sits before being cut,  the more stable it is in the long run.   I know it is usually not possible,  but I have had the best luck with wood that had been curing 10 years or more.  

[Mike Brooks]

I have had pretty much the same experience as Mike with expansion and shrinkage due to humidity.   In my current shop,  I use heat, air conditioning, humidifiers, and dehumidifiers to keep the humidity around 50-60% year round.   That way, there is little movement in the wood while I am building the gun.  

However,  once the gun leaves the shop and goes in the house,   I get noticeable shrinkage and swelling in ALL directions due to seasonal changes.  
When I worked in unconditioned space, the changes in the stock while I was working on it where just as Mike described.   In the summer,   I could be inletting a barrel that was going in and dropping out just fine.   A thunder storm could roll through (generally only 15 minutes and they are gone ), and at the end of it,  the barrel COULD NOT be removed from the stock until it dried out.  It would be like I super glued it in.  By the way shrinkage in low humidity is MUCH slower than swelling due to high humidity.   This is my actual experience.  

Also,  kiln dried wood is much more prone to movement than air dried wood.   The longer a stock blank sits before being cut,  the more stable it is in the long run.   I know it is usually not possible,  but I have had the best luck with wood that had been curing 10 years or more.  

I'm beginning to think we are actually Siamese twins that were separated at birth......

[Turtle]

 I have a NY rifle made from a cherry plank that was in a barn loft for over 50 years! Closest thing to "dead wood" I have ever experienced.
                                                     Turtle

[Acer Saccharum]

Wood will never stop moving.

I wonder if curly shrinks more longitudinally than straight grained wood.

Hmmm, now THERE is a poser for the twins!

[B.Habermehl]

Both, after I drill the pin holes in the lugs, I pull the barrel from the stock and drill two more holes in each lug one on each side of the original hole. Then I simply connect them using a jewelry saw. Dress them out a bit with a needle file and done. As others have posted figured wood moves a lot more than you would think. BJH