Craftsmanship > Gun Building and Repair

Wyosmith Building Tutorial

(1/7) > >>

Wyoming Mike:
The next message is the first installment of Steve's new tutorial on rifle building.  Hope it helps people get into this fun hobby.

Wyoming Mike:
The project I have to do is a simple Left handed flint rifle.  It's to be 40 caliber, swamped barrel.
It is to have a 14" length of pull, 2 1/4" drop at comb,  4" drop at heel and 8 3/4" drop at toe

It is to have 3/16 cast off to the left. (most cast off is to the right of course, but this is a LH rifle).
It is to be in a Lehigh County style, but starkly plain to keep it under budget.

I will start by laying out the rifle on paper.  This will allow me to lay out the proportions according
to the specifications I mentioned above.  I will use this pattern to rough cut the stock from the blank.

Lay the breeched barrel on a large enough piece of butcher paper.




The barrel is then traced onto the paper.




A line is drawn about 1/4" over the top of the barrel.  This is the line of sight.  All your drop measurements will be taken from here down to establish the stocks drop at comb, drop at heel and drop at toe.
In this picture I did it in blue so it's different than the black pencil lines.

The line for the barrel inlet section is drawn out.  The barrel tracing is biceted.  This line will be the top edge of the stock and it's breach end comes up to form the shoulder that will be the breaching shoulder. The lock plate is traced on now to set its relationship to the barrel.  The vertical line at the rear of the lock tracing is where the sear bar is on the lock.  This is needed for the next step.




Now, I draw in a line 14" long at a downward angle so I will have my pull length. This rifle has double set triggers, so I have to offset 1/2" to get the correct LOP.  In other words, you need to know that the trigger is sometimes farther forward to allow for set triggers.  In some cases you also have to offset a bit for single triggers too. That's why you need to trace the position of the trigger as it relates to the lock/sear, so you have a place to measure from.





From my line of sight I come down 2 1/4" for my drop at comb (which is always about 2" behind the nose of the comb where the wrist and comb come together) and I come down 4" at the end of the stock to get my drop at heel.

I trace in my buttplate being very careful to align the "return" of the butt plate with the comb line.

At this point I draw in the lines of the buttstock.  It's a Lehigh style on this rifle.  Once you have your drops and your length of pull, you just start to draw until you like what you see, but always keeping within the boundaries you set to make the gun fit the shooter.

Note that I leave about 1/4 of wood below the toe so it's not delicate as I inlet the butt plate later

I also leave about 3/16" of wood over the top of the breaching section so you have to go a bit deep there, and file the wood down as you inlet the barrel later.

These 2 places can be a problem if you cut your lines too tight, so leave a bit of wood and you will have fewer problems later.

I then come down from the bottom of the barrel tracing and draw in my ramrod, leaving 3/16" of "web" between the bottom of the barrel and the top of the rod channel.  The "web" is the wood between the bottom of the barrel channel and the top of the rod channel and hole.  With this gun, and any gun with a swamped barrel, you only measure at the breach and the muzzle 3/16" down, and let the web be a bit thicker in the middle where the wood will come up to meet the bottom of the swamp. My handrail section is 11" long, so I dogleg the drawing down to make the handrail section, and then bisect the rod from the entry point to the muzzle.  This gives you a channel half the depth of the rod diameter for the long section of the stock, and gives me an 11" deep hole in the handrail.




Here the stock is sawn out to the lines I drew and we have a stock ready to start building.

Wyoming Mike:
We are now beginning to inlet the barrel.  The photo the breach end of the barrel resting on top of the Breaching shoulder of the stock.  It's about to be inlet to the half way point.



 
I have now inlet the breach end inlet 1/2 way into the wood so the barrel now lays on top of the stock.  At this point the muzzle is clamped down so it can't move.  You can offset it to one side or the other to make the center line of the barrel cast off to the side....................



 
This rifle casts to the left, as it's a left hand rifle  This line is very important to the final fit of the stock, and should be drawn on with a marker so it won't rub off.  It's going to be there until we inlet the butt plate and shape the comb and the butt stock.



 
A chisel is sharpened all from one side for this cut.  You place the flat on the side of the barrel and hold it in place with the thumb.  Press only hard enough to keep it flat.  If you push hard you will flex the barrel.  YOU DON'T WANT TO FLEX THE BARREL SIDE TO SIDE, SO USE VERY LITTLE SIDEWAYS PRESSURE AS YOU DO THIS.


Lightly tap the chisel to make a cut on the top of the stock.



 
Here I use a 2" wide chisel to deepen the cut.



 
Here you see the side cuts set in about 1/16" deep.  I pencil down them so I can see them better.



 
I have drawn a cross section of a barrel channel.  On a swamped barrel, the muzzle is wider and deeper than the waist of the barrel, and so is the breach end.  

If you take 2 swamped barrels and lay them side by side on the floor, and then pinch then togather with your pinky and your thumb, you will see it takes VERY LITTLE to flex them.
 
When you flex the outside you flex and bend the bore.  If you want a swamped barrel to shoot well  it's ABSOLUTELY IMPERATIVE that the barrel not flex side to side or up and down when it's fully inlet.
 
I will make the first swath (A)  in the stock to the half depth of the side flat.  It's taller at the muzzle and at the breach than it is at the waist.  I will make the 2nd swath to make the bottom flat of the inlet (B) to make sure the barrel is at correct depth.  It's going to be 1/2 way into the wood, and it has to lay in a manor so that the bore remains straight.
 
So I measure the side flats with a caliper to the nearest .0001"  at increments of about 4" and I divide it by 2 to get the depth.  I do the same thing with the barrel itself to get the half diameter at about 3" increments



 
I have those written measurements on the top of the stock at the points that they relate to the barrel.
Depth of side flats and depth of barrel, both divided in half.
 
I will then inlet to those depth with my tools and scrapers until I have the barrel to correct depth.  I try to hold + or- .002" at every increment.  This is the secret to getting a swamped barrel to shoot tiny little groups
I will show you how that's done in the next instalment.

Uncle Russ:
I did my best to clean it up, and still keep things in perspective...

**Let's try hard to keep our responses to questions directly related to this particular project....Personal Messages go a long way in preserving such a valuable thread!

Thanks!

Uncle Russ....

Wyoming Mike:
Here is the next installment.  I broke the original from Steve into two messages because it was so large and had so many photos.

Navigation

[0] Message Index

[#] Next page