Barrel Gap from Warpage

[mgbruch]

Help!

I'm working from a blank (number 10), which I gave three months to acclimate, which is more than I have given some up here in the Northwest.  My barrel inlet was nicely done, and just a little snug.  After inletting for the barrel and ramrod groove, and drilling the ramrod hole... I band sawed the wood down to near final dimensions.  Next I inletted for the tang.  After three days time the stock is warping badly and I am at a loss.

The forearm is trying to warp down, which isn't a big problem.  The big problem is that the wood looks to be shrinking, and my barrel inlet is now too big pretty much all the way around.  It's worse on the lock side of the gun, but everything has warped away so that I now have gaps everywhere... some almost 1/16th of an inch.  The barrel now drops in as easily as it falls out.  Even the tang inlet is not tight after two days.

I am at a loss as to salvaging this build and still end up with a high quality gun I can sell.  I won't sell a gun I wouldn't own myself.  The only thing I can think of is that I could order a C weight barrel (inlet is for a B weight) and build something else with the stock.    I could probably drop a C weight in right now with little fitting.  I have 3/16th web at the muzzle, and just  a shade over 1/8 at the breech, so I do have enough wood there for the heavier barrel.  The wood is a grade five and has some really nice curl.

Any help you can give would sure be appreciated.  Many Thanks!

[rich pierce]

If it’s still slab sided but sawn to close to final dimensions along the barrel channel, I’d soak the heck out of it, get 3 heat guns on it with the barrel out, pop the barrel in, and hard clamp 2 angle irons to the sides to squeeze it inward. Clamp near the top of the sides.

[Scota4570]

I had a half stock that was really sloppy as prefit.  I soaked the forend with warm water.  I installed the barrel.  I then wrapped it with surgical tubing.  After drying for a couple of days there was no gap at all.  It has stayed tight for over 5 years. 

[Jim Kibler]

Here’s an easy fix…. Install your barrel.  Clamp the forend tight against the barrel with a number of c-clamps.  Using a heat gun, heat the stock starting at one end of the area in question and slowly work to the other end.  Heat it pretty hot, but you don’t want to scorch it.  Allow to cool and you should be good to go.  Quick and easy.

[Jim Kibler]

I should add, do this after the forestock is shaped out

[mgbruch]

Thanks Jim.

What do you mean by "after the forestock is shaped out"?  Final shaping of the fore end is the last step in shaping for me.  I'm pretty leery of putting in the rest of the work only to have to re-stock the gun (which I have done before... years ago).

Right now, the wood on each side of the forestock, ahead of the lock panel area, is between 3/16th ands 1/4 of an inch.  Eventually it will go down to 1/8", but not until the butt and wrist are about 95%.  I'm using a 44" swamped barrel.  Or do you mean to take the fore end down to 1/8" (still slab-sided) and then clamp it?

I fear that, in addition to warping, the wood has had shrinkage as well.  The tang inlet has loosened up a as well.  I always seem to get a little shrinkage after inletting; but it's not noticeable by sight... only by feel when inserting or removing a part.

As you can see; this one has got me worried.

[WKevinD]

You said you let the stock acclimate inside for three months, how dry was your blank  before your acclimating?
Sounds to me like it is still losing moisture.

Kevin

[alacran]

Where did your blank come from? Was the blank kiln dried? Which side of the Cascades do you live in? Wood behaves in mysterious ways. Sometimes what you think is shrinkage is actually expansion. Three months to acclimate is nothing. Three years would be better.

[mgbruch]

I live in Northeast WA, and the wood comes from back east, of course.  Three months is the longest I've let a piece of wood go before cutting into it.  Six weeks is more like it; and I've never had this problem with the nine guns I've built from blanks.  But... wood is wood, and sometimes it's gonna do what it's gonna do.

[bluenoser]

I assume you started with a kiln dried blank.  But, if not, the rule of thumb for air-drying hardwood is one year per inch of thickness.  That would equate to 2.5 to 3 years for a blank of average thickness.  One would be wise to check the moisture content with a protimeter before putting much work into a blank.  In addition, highly figured wood tends to have a lot more internal stresses than plain grain.  Stock removal allows the wood to wander to release those stresses.  A change in moisture content is another contributing factor.

[mgbruch]

Yup.

Tried clamping the stock to the barrel, and ended up with an 8 inch crack, beginning at the front of the lock panel.  Put some CA glue in it and clamped it.  We'll see... this piece of wood may be toast.  Every once in a while, someone gets what turns out to be a finicky piece of wood.  This time it happened to me.  I keep going through the building process in my head... but I didn't change sequence at all.  I did move faster though, in the process of removing wood.

It's got me stumped.  I sure do appreciate everyone's contribution, but I think we're done with this thread.  Going to order a new stock tomorrow, and just take the hit.

[Jim Kibler]

Thanks Jim.

What do you mean by "after the forestock is shaped out"?  Final shaping of the fore end is the last step in shaping for me.  I'm pretty leery of putting in the rest of the work only to have to re-stock the gun (which I have done before... years ago).

Right now, the wood on each side of the forestock, ahead of the lock panel area, is between 3/16th ands 1/4 of an inch.  Eventually it will go down to 1/8", but not until the butt and wrist are about 95%.  I'm using a 44" swamped barrel.  Or do you mean to take the fore end down to 1/8" (still slab-sided) and then clamp it?

I fear that, in addition to warping, the wood has had shrinkage as well.  The tang inlet has loosened up a as well.  I always seem to get a little shrinkage after inletting; but it's not noticeable by sight... only by feel when inserting or removing a part.

As you can see; this one has got me worried.

Clamp with barrel in place after the stock forestock is fully shaped.  Don’t know what other words to use.  There are limits to how far something can be moved. 

[alacran]

You live in a drier clime than where your wood came from. I have a quality moisture meter that I use to measure moisture content. I have brought kiln dried wood from Indiana to Arizona.
The wood came out of the Kiln at 7% moisture content.  After a month out of the kiln in Indiana, it varied from 9 to 10%. Where I live in AZ the climate is very close to Eastern Washington and Oregon.
It takes a year for the wood to peg at 6% humidity which is as low as my meter goes.

[Not English]

You can try steaming it. It's a  real gradual process. Don't overly stress the wood and leave clamped up until totally dry and cool. Another method is do as the birch bark canoe builders do. Use boiling water and apply soime pressure. add more boiling water further down the stock as it starts to move where you want it to go. Lots of clamps are essential. Besides heat, I think wood needs moisture to aid bending. I have no idea what will happen now that CA glue is involved.

[Jim Kibler]

You can try steaming it. It's a  real gradual process. Don't overly stress the wood and leave clamped up until totally dry and cool. Another method is do as the birch bark canoe builders do. Use boiling water and apply soime pressure. add more boiling water further down the stock as it starts to move where you want it to go. Lots of clamps are essential. Besides heat, I think wood needs moisture to aid bending. I have no idea what will happen now that CA glue is involved.

No, moisture is not required.  Heat alone will work fine and is MUCH easier per the method I described previously.

[Long John]

Friends,
 Mr. Kibler is right on with his heat-gun method.  Your average kiln-dried billet of wood is about 8% water, by weight.  This water is in the form of water molecules that form chemical bridges between adjacent cellulose and lignin fibers that make up the wood.  When you heat the wood up those water molecules become fee to move around within the wood.  The clamps tell the wood where you want it to go.  The heat scrambles up those water molecules so that they can make new bridges between re-positioned cellulose and lignin fibers.  As long as you don't heat the wood too hot - it starts to change color becoming brown - the water molecules don't leave the wood.  They just relocate within the wood.  Guitar and banjo builders hot bend wood all the time.

Best regards,

JMC

[Eric Krewson]

I have posted this before; I have done thousands of heat straightening's of osage wood for bows. I had a precarve shipped back to me after they lost the barrel temporarily, without a barrel in the inlet the forestock warped down at a 30-degree angle. First, I heated the barrel to about 150 degrees and put it in the barrel channel. While I was doing this, I was heating the forstock with sweeping strokes from a heat gun. As I was heating the forestock I was putting light pressure on it to see when it became pliable, the forestock started to move when it was just about too hot to touch, at this point I gently pushed it into place and zip tied it tightly up and down the barrel, all the time keeping the heat on it and the barrel.  After I had everything in place and zip tied, I wrapped several old tee shirts around the barrel and forstock to hold the heat and let it soak in and make permanent corrections. With the hot barrel everything stayed hot for about 1/2 hour.

The end result was a very straight stock than has never changed over time.

On osage wood I use a piece of aluminum angle to hold the heat and give the angle and wood an insulating wrap of old tee shirts to hold the heat.

[Fly Navy]

I use heat to straighten ramrods all of the time.

[flehto]

Had warpage and "slop" between the inlet and the bbl on a precarve so soaked the stock in water for a few days and then put the waxed bbl in and used surgical tubing tightly wound on  the bbl and stock. After 2 weeks took the tubing off and the stock was perfect. From then on made all my builds from thoroughly dried blanks,.....Fred