Butte plate gap

[windjon]

What should I do here? One of two rifles I'm working on is a .32 Vincent build.(my son wanted a percussion squirrel rifle) Everything i inlet was nice and tight when I set it aside in March. Took an engraving class in May and after many hours of practice at home decided it was time to install and attempt the patch box and inlay engravings. Looked at the bottom of the butte plate to find a gap. I have noticed that a couple of other builds had the wood at the toe swell past the butte plate only to return even in the fall. This really did not seem like a problem on a early gun as no gaps are present. Should I inlet the butte plate in more or leave it alone. Im afraid if I tighten this up, when the humidity goes down , the delicate toe area could crack if it moves back. Advise and thoughts would be greatly appreciated.
March

July

[Dennis Glazener]

I would remove the toe plate and see what happens. If the buttplate tighten's up I would shorten the toe plate and call it good.

If the buttplate doesn't tighten up I would re-inlet it so it fits tight and still shorten the toe plate to fit tight. If the wood moves again, any gap would be associated with the toe plate and at least the "expansion joint" would be on the bottom/toe plate.

When dealing with some wood you can't predict how it will act over time. At least that's been my experience.

Dennis

[Mark Elliott]

Assuming your verify that the toe plate isn't the problem,  I would normally deal with this situation by peening the edge of the butt piece tight to the wood.   This is my normal procedure in the final fitting of butt pieces.   Brass butt pieces may need to be annealed in the area with the gap before you do this as they will harden where you hammer them.   

The problem with doing this on your rifle is that there is so little wood at the toe.   I think you could get away with hammering the gap closed if you had someone hold the rifle (or you could clamp the rife) such that the toe was completely backed by something solid.    I would probably want it set flat on my anvil.   Still,  I would use light taps on the edge of the butt piece.   A lot of light taps will close up a gap with annealed brass or thin steel.   

While i have used this method to fit a highly curved steel butt piece on an E. TN, I don't think it had quite such thin a toe.   The call is going to have to be yours, but I thought I would offer another option.
   

[Mark Elliott]

Before you do anything,  let me ask this; is the stock quartersawn? If so,  you have the gap because, as you suspected,  the entire butt swelled along the vertical axis.   Come winter, It will shrink again and probably close the gap.   The tendency will be for this swell/shrink cycle to go on forever with the stock gradually shrinking more and more each time.   This is why the toe is at least cracked on just about every antique longrifle.    That is inevitable unless the gun is kept in a well controlled environment all the time, such as in a museum.     

The thing is, how much gap do you want to tolerate in the summer in the mean time?    If you do nothing,   the gap will gradually close up over the years, until the toe breaks.    You might split the difference and wait until October to close the gap by peening.   That will close the gap pretty tight such that when it opens in the Summer,  it will probably be hardly noticeable.   Looking at the picture from March,  it doesn't look like the fit was as tight as it might have been in the toe.    My meaning being,  there may be some wiggle room in closing the gap. 

Just some thoughts.   You have to understand that from the time you put stain on a stock,  nothing ever fits the same again.   Something is always going to be off somewhere.   It is the nature of wood.   Butt pieces never fit right again once you take them off after final fitting.   Fit is always a matter of degrees. 

[Joe S.]

I'm going thru the same thing with my build.Started it in April and am finding things tuff when the humidity goes up things don't fit the way they did before.Like the others said such is the way of wood.I'd be scared to peen that thing in place for fear of cracking the toe.Maybe take it off and put it in the vise and try ever so slightly a bend to tighten it up,thing is when it wants to return its going to put pressure on and may crack.Listen to folks here they been there and done that,I'm new to the game and learning right along with you.

[Pete G.]

Shorten that toe plate a little. If there is any gap left it will not show after stain and finish. If you fool around with that sharp toe of the stock too much you risk cracking it.

[Acer Saccharum]

Wood is going to move, no matter what you do. I've fit perfectly tight plates, and in two months, some imp has made gaps appear.

It appears the the wood is shrinking, and the stress is between the toe plate and buttplate. If you shorten toe plate a gap will appear at the BP when the wood swells up again.

Fix: get a carbon fiber stock. 

[David Rase]

Before you do anything,  let me ask this; is the stock quartersawn? If so,  you have the gap because, as you suspected,  the entire butt swelled along the vertical axis.  

Mark,
I must ask, what difference does it make whether the stock is quarter sawn or slab sawn when we are talking about seasonal changes to the length of a gunstock?  I understand that wood swells and shrinks in all directions, but in my little pea brain, vertical axis is still vertical axis and it should not matter since quarter sawn or slab sawn is the way the log was oriented and cut at the saw mill in relation to the growth rings.
David
  

[FDR]

A more basic question would be: "did you seal the end grain and inlets"? If the answer is "no" sealing will help.

Fred

[Mark Elliott]

+Before you do anything,  let me ask this; is the stock quartersawn? If so,  you have the gap because, as you suspected,  the entire butt swelled along the vertical axis.  

Mark,
I must ask, what difference does it make whether the stock is quarter sawn or slab sawn when we are talking about seasonal changes to the length of a gunstock?  I understand that wood swells and shrinks in all directions, but in my little pea brain, vertical axis is still vertical axis and it should not matter since quarter sawn or slab sawn is the way the log was oriented and cut at the saw mill in relation to the growth rings.
David
  

David,

Wood swells differently in different directions.  It is not like how a non-organic material (such as brass, iron, or plastic) swells and shrinks due to temperature.   It swells based on how it absorbs moisture from the air.  The most swelling due to humidity is perpendicular to the growth rings.   That means that the wood will move most up and down in a quartersawn stock.  That is why it is preferable to use a quartersawn stock.   It will warp in the vertical plane, meaning that you only have to adjust sight elevation to compensate for the  movement imposed on the barrel, as opposed to windage.   A quarter sawn stock would swell in the butt such that the toe would move down and away from the butt piece giving you a gap between the butt piece and toe plate, if there is a toe plate.  Otherwise, there will just be a little oozing of wood at the toe and maybe a gap.   That is what we see happening in the photos posted here.   Given that the butt piece is fixed at the top and the bottom screw,  the only place the wood can move is in the toe.

A slab sawn stock will swell the most to the sides.   This would be indicated by the wood appearing to ooze out at the sides of the butt piece.   The most seasonal swelling you will see in the length of a 5' long gun stock is maybe 1/16".   You can easily see that much swelling across a 2" buttpiece (1/32" on either side) from Winter to Summer depending on when you stocked the gun.   

How much a piece of wood shrinks or swells due to humidity depends on the species of wood,  how it grew (number and size of growth rings, etc....), and how it was dried.   Kiln dried wood will absorb more water and thus move more than properly air dried wood (at least one year for each inch of thickness).    The longer the wood has been allowed to air dry, the less movement (shrink/swell or warpage) after it has been fashioned into a gun stock or anything else for that matter. 

The above is my current understanding and observation about the behavior of gun stock wood.  If I have gotten anything wrong,  I would welcome correction from someone more knowledgeable about the behavior of wood.

[Joe S.]

Thank you for your explanation on what's best for gunstocks Mark.My experience with wood come from the building industry. The riddle of wood has always been just that a riddle.Two pieces appearing to be identical will act totally different.Houses built in the winter,spring with settle different than houses built in summer,fall for instance.Types of lumber,how its handled how its allowed to cure ect.àll play a part.Hardwood flooring must be allowed to acclimate to the house it's going to be installed in to get the best results. This is why you can't get to bent when a little gap appears in your build ,you don't have control over it for the most part.

[David Rase]

Since I am starting to build a few cabinets and furniture, I have been interested in annual dimensional changes in wood and have been doing some research.  Even though most of the information in books and on line is for lumber, it can still be adapted to gunstocks.  I have not dug down into the weeds yet on the differences between walnut and maple, but I am sure they react differently to seasonal changes.  Below are some generalities I have come up with, you can take them for what they are worth.

1.  Wood is constantly expanding and contracting. duh! 
2.  Wood does not move equally in all directions. The grain structure causes it to move differently in three different directions.
3.  Wood is fairly stable along its longitudinal direction, parallel to the grain. Lumber shrinks only about 0.01 percent of its length as it dries. An 8-foot-long board would only move about 3/32 inch.
4.  Wood moves much more across the grain, tangent to the growth rings. As much as 8 percent shrinkage can be expected in this direction.
5.  Wood only shrinks half as much (4 percent) in the radial direction, extending out from the pith along the radius of the growth rings.
6.  Plain-sawn boards tend to cup when they expand and contract
6.  Using the above information, I would say that quartersawn lumber is more stable than plain-sawn lumber based on the fact that quartersawn lumber is cut radially and moves only half as much across its width as plain-sawn lumber, which is cut tangentially.

David

[windjon]

Thank you for the replies. To answer you Mark, the blank was a plain sawn curley maple. However, the growth rings run perfectly vertical through its entire length. I did not expect such a dramatic change, at least away from the butte plate. On my next build(a southern mtn rifle) there will be less of a crescent butte plate.
On the Vincent then I will go ahead and inlet the patch box and several more inlays, practice more on engraving and by then I should have an idea of how the stock is going to behave with less humidity.

[D. Taylor Sapergia]

The wood at the toe, next to the butt plate has shrunken a bit, and the step in your toe plate is preventing the brass to follow.  Shorten the toe plate to allow the brass to follow the wood.

[windjon]

Thanks Dennis and Taylor. Feeling a little embarrassed.

[D. Taylor Sapergia]

Nice!

[Mark Elliott]

Well that's great!     

The only shrink/swell issue I usually struggle with is the patchbox lid fit and the patchbox release.  It generally takes a year to get it all adjusted just right.  I have made changes to my release mechanisms to make the shrink/swell less of an issue.  The main thing is to allow plenty of travel in the release button/pushrod.  i was making them way too tight.    I now routinely rivet my release buttons to a metal tab riveted to the toe plate (for those with a toe plate release - the other types of releases are less troublesome).   That generally gives you all the travel allowed under the tab/toe plate and you can make all types of buttons.    Also,  the button doesn't need to line up perfectly with the push rod.   John Davidson used a bell crank mechanism to handle the button/pushrod offset.   That is more trouble than I would like to go to if I am not making a Davidson.