Gunload Master
07-13-2008, 12:21 AM
Cutting Dovetails by Hand
By Jim KCSO
*
Let’s start this off by my issuing a disclaimer; I’m not an expert at anything. I am a poor country boy gunsmith who has been lucky enough to be able to learn from his elders. What I am passing on here I was fortunate enough to pick up from folks like Greg Roberts of the Green River Rifle works, Bill Large, Doc Carlson and V.M Starr. I have cut enough dovetails by hand so that is I don’t happen to have a 5/16 rougher in the mill I will just cut one rather than take time to set up the mill. If you work slowly and carefully you can cut as neat and as well a fitting dovetail as any machine. So listen up…
Tools required:
1 square file, preferably with a safe edge
1 Triangular file 60 degree with, safe edge REQUIRED
1 small square
1 depth gauge, this doesn’t have to be fancy my favorite was made from a broken CB antenna.
1 Hacksaw with a 24 tooth blade.
The safe files should look like this…
http://castboolits.gunloads.com/images/members/Dovetails 004.jpg
I ordered these files from MSC and made the safe edges by grinding them flat on a grinding wheel. I kept the temper by keeping them wet and keeping my finger on the stock as I ground.
To start the dovetail take a square and mark the barrel with two lines just smaller than the top of the dovetail. You want to err on the side of caution here as you can always make the dovetail bigger but you can’t very well make it smaller. The take the sight and make sure that all casting lines and burrs are removed the base of the sight should be clean and smooth or the sight won’t fit properly.
http://castboolits.gunloads.com/images/members/Dovetails 001.jpg
Here is the barrel with the sight and the square on it. Notice that the pencil lines are NARROWER than the top flat of the intended sight.
Now that the dovetail is marked out you need to make two cuts inside the lined you just marked. I use a 24 tooth hacksaw as it is less likely to catch and slip as compared to an 18 or a 10 tooth blade.
http://castboolits.gunloads.com/images/members/Dovetails 002.jpg
The first two cuts should be shallow and you will FILE the cuts to final depth. I don’t measure this I just eyeball it. After you get the first two cuts made go inside those cuts and make several more like this.
http://castboolits.gunloads.com/images/members/Dovetails 003.jpg
Now you take the square file and clean out the blank and square it up. Work slowly and try not to mar the top flats of the barrel. Use the safe edge of the file against the outside of the work to be removed and cut from both sides to the inside. When you have the scrap removed then square up the cut and cut down to just under the proper depth for the sight. You need to leave about 5 thousands for clean up as you work the square cut into a proper dovetail.
http://castboolits.gunloads.com/images/members/Dovetails 005.jpg
Here the cut is nearly squared and the depth gauge is ready to check depth of the cut. A fancy tool isn’t necessary for this, but a Harbor Freight dial caliper will only set you back $12.95.
Once the cut is squared and nearly to depth take you triangular safe file and lay it in the cut with the safe end to the bottom and start cutting each end to form the dovetail.
http://castboolits.gunloads.com/images/members/Dovetails 006.jpg
When you are cutting to the ends you will notice that the dovetail will start to curve up away from the bottom of the cut. Viewed from the side the dovetail will be curving up. Take the safe file and turn the safe edge into the dovetail and square the cut ever so often so that as you view the cut from the side it is flat and square.
http://castboolits.gunloads.com/images/members/Dovetails 007.jpg
As you look at this you can see the edges of the dovetail are not sharp and are starting to curve slightly, it’s time to turn the file and flat them out.
As you get close to the final size of the dovetail try the sight in the cut every few cuts. As soon the sight will start in the dovetail go slow and work to clean up, sharpen and square the dovetail.
http://castboolits.gunloads.com/images/members/Dovetails 008.jpg
The dovetail is close at this point and you want to go slow here and try the sight in the cut ever couple of file strokes. You want the sight to go in with just enough resistance so that a light tap with a brass punch will move it back and forth. You NEVER want a cut so tight that you have to pound on the sight to move it, or deform the sigh to make it move. When the gun is sighted in you take a center punch and lock the sight in place with a punch mark. Most factory sights are WAY too tight in the dovetail as they are pushed into place with a hydraulic ram. This can actually cause a thin walled barrel to deform and put a wrinkle under the sight on the inside of the bore. I have had several factory 45 caliber guns that had to have the barrels cut back and re dovetailed by hand because the bore was deformed under the factory dovetail. In a number of cases the reason for this was that the bottom flat of the front sight had not been properly smoothed.
http://castboolits.gunloads.com/images/members/Dovetails 010.jpg
Here is the finished dovetail with the sight in place. There are no gaps under the sight and the top of the sight base is flush with the top flat of the barrel.
Now I don’t time any job in my shop as I don’t work to a clock, I prefer to just keep plugging and make sure the job gets done right. With practice I would guess that it should take less than ½ hour to cut a proper dovetail. Even if it takes you 1 ½ hours to do the job, you can balance that against the $35 a machine shop will charge you. Any you have the satisfaction of having done it yourself.
*
By Jim KCSO
*
Let’s start this off by my issuing a disclaimer; I’m not an expert at anything. I am a poor country boy gunsmith who has been lucky enough to be able to learn from his elders. What I am passing on here I was fortunate enough to pick up from folks like Greg Roberts of the Green River Rifle works, Bill Large, Doc Carlson and V.M Starr. I have cut enough dovetails by hand so that is I don’t happen to have a 5/16 rougher in the mill I will just cut one rather than take time to set up the mill. If you work slowly and carefully you can cut as neat and as well a fitting dovetail as any machine. So listen up…
Tools required:
1 square file, preferably with a safe edge
1 Triangular file 60 degree with, safe edge REQUIRED
1 small square
1 depth gauge, this doesn’t have to be fancy my favorite was made from a broken CB antenna.
1 Hacksaw with a 24 tooth blade.
The safe files should look like this…
http://castboolits.gunloads.com/images/members/Dovetails 004.jpg
I ordered these files from MSC and made the safe edges by grinding them flat on a grinding wheel. I kept the temper by keeping them wet and keeping my finger on the stock as I ground.
To start the dovetail take a square and mark the barrel with two lines just smaller than the top of the dovetail. You want to err on the side of caution here as you can always make the dovetail bigger but you can’t very well make it smaller. The take the sight and make sure that all casting lines and burrs are removed the base of the sight should be clean and smooth or the sight won’t fit properly.
http://castboolits.gunloads.com/images/members/Dovetails 001.jpg
Here is the barrel with the sight and the square on it. Notice that the pencil lines are NARROWER than the top flat of the intended sight.
Now that the dovetail is marked out you need to make two cuts inside the lined you just marked. I use a 24 tooth hacksaw as it is less likely to catch and slip as compared to an 18 or a 10 tooth blade.
http://castboolits.gunloads.com/images/members/Dovetails 002.jpg
The first two cuts should be shallow and you will FILE the cuts to final depth. I don’t measure this I just eyeball it. After you get the first two cuts made go inside those cuts and make several more like this.
http://castboolits.gunloads.com/images/members/Dovetails 003.jpg
Now you take the square file and clean out the blank and square it up. Work slowly and try not to mar the top flats of the barrel. Use the safe edge of the file against the outside of the work to be removed and cut from both sides to the inside. When you have the scrap removed then square up the cut and cut down to just under the proper depth for the sight. You need to leave about 5 thousands for clean up as you work the square cut into a proper dovetail.
http://castboolits.gunloads.com/images/members/Dovetails 005.jpg
Here the cut is nearly squared and the depth gauge is ready to check depth of the cut. A fancy tool isn’t necessary for this, but a Harbor Freight dial caliper will only set you back $12.95.
Once the cut is squared and nearly to depth take you triangular safe file and lay it in the cut with the safe end to the bottom and start cutting each end to form the dovetail.
http://castboolits.gunloads.com/images/members/Dovetails 006.jpg
When you are cutting to the ends you will notice that the dovetail will start to curve up away from the bottom of the cut. Viewed from the side the dovetail will be curving up. Take the safe file and turn the safe edge into the dovetail and square the cut ever so often so that as you view the cut from the side it is flat and square.
http://castboolits.gunloads.com/images/members/Dovetails 007.jpg
As you look at this you can see the edges of the dovetail are not sharp and are starting to curve slightly, it’s time to turn the file and flat them out.
As you get close to the final size of the dovetail try the sight in the cut every few cuts. As soon the sight will start in the dovetail go slow and work to clean up, sharpen and square the dovetail.
http://castboolits.gunloads.com/images/members/Dovetails 008.jpg
The dovetail is close at this point and you want to go slow here and try the sight in the cut ever couple of file strokes. You want the sight to go in with just enough resistance so that a light tap with a brass punch will move it back and forth. You NEVER want a cut so tight that you have to pound on the sight to move it, or deform the sigh to make it move. When the gun is sighted in you take a center punch and lock the sight in place with a punch mark. Most factory sights are WAY too tight in the dovetail as they are pushed into place with a hydraulic ram. This can actually cause a thin walled barrel to deform and put a wrinkle under the sight on the inside of the bore. I have had several factory 45 caliber guns that had to have the barrels cut back and re dovetailed by hand because the bore was deformed under the factory dovetail. In a number of cases the reason for this was that the bottom flat of the front sight had not been properly smoothed.
http://castboolits.gunloads.com/images/members/Dovetails 010.jpg
Here is the finished dovetail with the sight in place. There are no gaps under the sight and the top of the sight base is flush with the top flat of the barrel.
Now I don’t time any job in my shop as I don’t work to a clock, I prefer to just keep plugging and make sure the job gets done right. With practice I would guess that it should take less than ½ hour to cut a proper dovetail. Even if it takes you 1 ½ hours to do the job, you can balance that against the $35 a machine shop will charge you. Any you have the satisfaction of having done it yourself.
*