January 5, 2011

Converting a 1915 Stevens Favorite

Turning a wallhanger into a shooter is a project every gunsmith ought to try at least once. Here’s what one ‘smith did to a .32 Long Stevens rifle.

you do gunsmithing for any length of time, you develop a preference for certain types of jobs. Restoring what seems to be a hopeless case gives me the most gratification. Collaborating on ideas with the customer, discussing what can be done and what is impractical, is sometimes as challenging as completing the project itself.

There are countless special projects the experienced gunsmith can make a living on but there are probably as many that an enthusiastic gun owner can accomplish with time and patience. Garage sales, estate auctions and newspaper ads can produce a gem of a project every now and then. In my mind, spending the long winter months doing this is much better than channel surfing the television. Whether the subject of your project is completely restoring an obsolete revolver, shotgun or rifle, or merely refurbishing a semi-modern design, you’ll no doubt learn more about that particular firearm than you knew before you started.

That certainly was the case with a Model 1915 Stevens Favorite I acquired not long ago. I won’t tell you the price I paid because you’d probably get mad at me. The problem was that the rifle was chambered for the old and obsolete .32 Long rimfire caliber. Researching this rifle became almost an obsession to me. Among other things, I learned that ammunition was going to be difficult to obtain and not all that impressive if I could find it. The .32 Long rimfire’s ballistics have me convinced I would do better hunting with a club than the round. The load’s effective range is about 50 yards and it has a rainbow-like trajectory.

During a temporary lull at the shop, it occurred to me that the old rifle just might be worth converting to .22 rimfire caliber. Then I had to figure out exactly what it would take in order to accomplish that objective.

Obviously, something had to be done about the barrel and the .32 caliber hole running through it. The ammunition for this rifle used a charge of 12 to 13 grains of blackpowder to propel a 90 grain lead bullet. Up until about 1927, rimfire primer mixes used mercury styphinate, which is very corrosive. This combination of blackpowder and corrosive primers was harmful to the softer steel barrels of the day, especially if they weren’t cleaned shortly after shooting. My only apparent options were to sleeve or reline the barrel to .22 caliber or to use a .22 caliber octagon blank and replace it outright.

I chose the second option because the shank of the barrel that went into this particular receiver did not fit as tightly as I thought it should and I could get a .22 caliber octagon barrel blank from Gun Parts, Inc. for about $8 more than a barrel liner cost. If you want to keep the original barrel on the Favorite rifle you are restoring, a sloppy fit can be fixed by knurling the barrel shank. Set up the barrel in your lathe and use a knurling tool on the shank, which will raise the metal in the area about 0.010-inch. The knurling, which resembles metal checkering, can then be turned down until the shank-to- receiver fit is tight. A knurled-head takedown screw on the bottom front portion of the receiver secures the barrel to the receiver. Once this screw is backed off, the barrel can be separated from the receiver.

When the new barrel blank arrived, I cleaned it with petroleum solvent to remove all grease and thoroughly inspected the barrel’s quality. The blank, approximately 24 inches long, measured just less than 0.75-inch across the flats although there were slight deviations at various points. Some of the edges along the octagonal flats were dinged a bit as well, so I decided to true up the barrel in the milling machine. One end of the barrel was placed in a tailstock center at one end of the mill’s table and the other clamped tightly in a milling vise. The table was run back and forth, with the barrel held under a dial indicator to ensure that the milling would be on a flat and straight plane. After determining the lowest point of each octagonal flat, it took eight passes with the milling cutter, removing an average of 0.010-inch on each pass, to true up the outside of the barrel. This was done to make sure all the barrel’s flats were the same size and distance from the bore centerline and that all the little manufacturing dings and dents were removed.

The next step in the process is draw filing each barrel flat to remove the endmill tool marks. (If you have a surface grinder, by all means employ it on this stage. It sure beats the arm-tiring drudgery of draw filing.) Draw filing is done with a smooth cut file, holding the file teeth at 90 degrees to the face of the flat. The file is then drawn back and forth, shaving metal as you go. Rubbing some chalk into the teeth of the file will prevent metal slivers from hanging up in the file teeth and galling or gauging the surface you are trying to keep smooth. Use a file card (steel wire brush) to clean out the teeth regularly and add chalk frequently. This will keep you from having to do more sanding than necessary when you are getting the metal down to the desired finish.

American Gunsmith, Gunsmithing the Rifle

American Gunsmith, Gunsmithing the Rifle

In its original condition and caliber, the 1915 Stevens Favorite is little more than a wallhanger.

The barrel shank that goes into the front of the receiver needs to be turned down next, with an eye to achieving as tight a slip fit as you can. An adjustable jaw lathe chuck, along with a dial indicator to remove as much runout as possible from the bore, is necessary for this operation. Place the point of the indicator in the bore on top of the lands and adjust the jaws of the chuck so there is no more than 0.0005-inch of travel on the indicator as the chuck is turned by hand. The extension on the original barrel going into this Favorite’s receiver measured 0.664-inch in diameter, which I felt was a bit sloppy. The shank on the new barrel blank was turned to a diameter of 0.666-inch. It fit much better and had no wobble. Once the barrel shank was turned to the proper diameter, I swapped the barrel end-for-end in the chuck. At this stage, the muzzle indicated true and a crown was cut to protect the rifling. I used a recessed-style target crown.

On the original .32 caliber rimfire barrel, the extractor is positioned at the bottom of the rear face. The original extractor groove, which measures 0.187- inch wide and about 0.125-inch deep, is wider than necessary to extract a .22 rimfire case. A new groove needed to be milled into the new barrel’s bottom rear face. I determined that a groove width of 0.093-inch was more than strong enough to remove spent .22 caliber cartridge cases. The groove’s depth was to be 0.100-inch. An extractor groove can be cut with a file but machining is generally more accurate as long as your machine and part setup is error-free. Here’s how I did it:

The new barrel was placed in a milling vise on the milling machine with the barrel shank pointing to the right of the mill table. An 0.093-inch-thick by 0.312-inch diameter Woodruff-style cutter was then colleted tightly in the quill. Half of the barrel shank and half the cutter width add ups to a figure of 0.379-inch. The bottom face of the cutter was lowered until it just touched the top of the barrel shank and a dial indicator with a full inch of dial travel was zeroed up against the lower face of the quill. After moving the table to get the cutter off the barrel shank, the cutter was fed down until the dial read 0.379. The quill was then locked in place. This put the center of the cutters teeth in the center of the barrel shank. Ten passes of the cutter, infeeding 0.010-inch with each pass, cut the extractor groove to the proper depth. The original extractor needed to be adapted to the smaller rim diameter of the .22 rimfire case and the new extractor groove’s width in the barrel before the barrel could be chambered and headspaced.

Four screws hold the internal parts in place inside the receiver. On the model 1915, all the screws come out the left side. The screw directly over the trigger is the trigger pivot screw. Just above that one is the hammer pivot screw. The screw in the receiver just forward of the trigger guard is the lever pivot screw. The one just above and to the front of the receiver is the breech block pivot screw.

For complete disassembly, all four screws need to come out, as does the hammer spring retaining screw. The screws also act as pivot screws for each part. If one or all of the parts has a sloppy fit on its respective pivot screw, there are two options: You can make a new screw or drill out the pivot screw hole in the part and solder a bushing in place to tighten up the play. All the screws, including the knurled takedown screw, come in “oddball sizes” like 0.312-inch diameter by 30 lines per inch thread. I am not aware of any thread dies that are available for such sizes so if new screws are made, their threads would have to be turned on a metal lathe.

If you choose to drill out the pivot hole to the next larger common size, take care to go only large enough in size to get a round hole without breaking through the side walls of the part. Turn a bushing to fit inside the new hole with the inside diameter of the bushing 0.001-inch larger than the pin diameter. The bushing can be made to a press fit or be hard-soldered into place. By letting the bushing protrude a little at each side, excessive left- to-right movement of the part when it’s in position inside the receiver can be eliminated by adjusting the bushing’s width.

The original extractor’s loose and sloppy fit in the original barrel’s groove was no problem. Both sides needed to be dressed down so the extractor would fit in the new barrel’s 0.093-inch groove. The end of the extractor that fits underneath a .22 case rim had to be lengthened about 0.060-inch. This was done by using 4130 chrome-moly welding rod to build up the end of the extractor until it was long enough to fit properly. Having a little more material here than you need is preferable to coming up short because you don’t have enough.

American Gunsmith, Gunsmithing the Rifle

American Gunsmith, Gunsmithing the Rifle

The receiver was terribly rough before polishing. All the screws had uncommon threads. From the left: No. 1 measured .218 x 36 TPI. No. 2 measured .187 x 26 TPI. Nos. 3 and 4 measured .158 x 30 TPI.

The target width for the new extractor was 0.090-inch, which provided 0.0015- inch of clearance on each side to prevent binding. The extractor was placed in the receiver to make sure that it fit properly. Vertical and horizontal movement was also checked. The top of the extractor was dressed down and blended into the rifled bore with a tapered carbide burr bit running at slow speed in a moto-tool. You cut the groove in the extractor for the .22 case rim when the barrel is chambered with the extractor in place. Once the extractor is fitted into the barrel recess, the barrel will settle back into the receiver in its proper position and the breech block can be closed completely. The extractor, positioned in its barrel recess, will also help prevent the barrel from turning inadvertently.

To mark the barrel for the recess needed for the takedown screw, I made up a center punching device that was 1/4-inch long with an outside diameter of 0.280-inch and one end turned to 60 degrees. The pin punch was inserted into the hole threaded in the receiver for the takedown screw and the takedown screw turned in behind it. This left a punch mark in the barrel shank at the exact position needed for the takedown screw’s reception. A 9/32-inch drill would fit into the threaded hole but the drill’s runout could possibly damage the crown of the threads in the receiver. I didn’t want to risk the threaded hole being cut any larger by the sides of the drill.

The takedown screw tip has an angle of 63 degrees or 27 degrees, depending on how you check it. The recess in the barrel shank has a matching tapered hole—undoubtedly put there with a special end-cutting factory tool—to receive the takedown screw and secure the barrel to the receiver. The only reason I can think of for this matching taper affair is to reduce wear. If the barrel shank fits the receiver tightly enough, the screw only needs to hold the barrel. Unless the takedown option is used excessively, there is really no need to replicate the tapered hole in the barrel shank.

A micrometer check showed the midpoint diameter of the taper on the takedown screw to be 0.250-inch, the size of the blind hole drilled into the barrel shank. Beginning with a 1/4-inch twist drill, with the cutting tip ground at a 135 degree included angle, a starter hole was cut to a depth of 0.125-inch at the punch mark. The barrel shank diameter is 0.666-inch and the bore diameter is 0.224-inch. Subtracting the inside diameter from the outside diameter gives 0.442-inch. Halving this gives you 0.221-inch shank wall thicknesses. Finishing the blind takedown screw hole to a depth of 0.150-inch with a 1/4-inch flat bottom, center cutting, end mill or twist drill will give plenty of depth to the hole and leave enough bore wall thickness to keep things safe.

A .22 rimfire caliber barrel can be easily chambered by hand-turning the proper chambering reamers because the process involves very little metal removal. You should regularly oil the reamers after brushing the chips out of the flutes to prevent a chip from scoring the chamber walls. These chamber reamers must be turned only in a clockwise direction and pulled backward when removed. Turning the reamers counterclockwise will cause them to prematurely lose their edge and could ruin them. As you approach the finished chamber depth, start checking the chamber with a .22 caliber dummy round. The reshaped extended extractor should be cut right along with the chamber and rim for the .22 caliber case. All .22 caliber rimfires headspace on the rim so when you begin to cut the rim to depth, check the headspace as you go.

Two sight dovetails, one for the front sight and one for the rear, are cut into the original barrel. I opted to use the two screw holes that were already in the top tang for a vernier sight so I only needed to cut a dovetail for the front sight. The original front sight was in good enough shape to be used on the new barrel.

The barrel was set up in the milling vise with the extractor groove pointing down, which also provided a visual reference so I could be sure I was dealing with the top flat of the octagonal barrel. A dial indicator was used to check alignment along the side of the barrel and the straightness of the barrel in the vise. This is an important step, as we don’t want to end up with a crooked dovetail for the front sight. An edge finder was colleted in the mill and run up against the front face (muzzle) of the barrel. Once the edge finder was running true, the mill table was moved 1.125 inches away from the muzzle to the dovetail slot’s planned location. An edge finder is a device that is of a known diameter, in this case 0.500-inch. The very end of this tool goes up against the edge of the part to be centered under the mill’s collet. The tip of this edge finder is spring-loaded and runs out of true by design. When contact is made with the part, the table is moved until the tip runs true with the shank of the edge finder. Then you know you are at the exact edge of the part. This is done while the quill is turning. The milling machine table is then moved the desired distance, plus half the diameter of the edge finder. You should be at the exact spot where you want to make your endmill cut. In this case, the center of the front sight was to be 0.875-inch from the muzzle, to which we add half the diameter of the edge finder (0.250- inch) for 1.125 inches.

American Gunsmith, Gunsmithing the Rifle

American Gunsmith, Gunsmithing the Rifle

Set up in the milling vise, the extractor groove in the new octagonal barrel is cut 0.093-inch wide and 0.100-inch deep with a Woodruff keyseat cutter. The breech block is bushed for an 0.052 offset hole for the new firing pin. The old pin is shown next to the new one to give you an idea of why a replacement was needed.

The first, or rough, cut was made with a 0.375-inch diameter endmill to a depth of 0.080-inch, in two 0.040-inch increments. The four-flute 3/8-inch endmill was then replaced in the collet by a dovetail cutter with a 60 degree shoulder measuring 0.300-inch in diameter at the large end. The roughed-in mill cut was painted with layout dye so I could see when the dovetail cutter just started to scratch the bottom. Dovetail cutters should be run at a low speed, about 300 rpm, and fed into the work at a slow rate to avoid breaking their teeth. The undercuts were made in the front sight dovetail while I checked to see when the front sight would fit properly. Once the front sight was attached, the barrel work was complete except for drilling and tapping the forearm attachment screw hole and blueing.

The next step was adapting the breech block to the new firing pin needed for the .22 rimfire cartridge. Digging around in my miscellaneous parts drawer, I found an old copper-cased .32 rimfire round. The rim diameter of this case measures 0.375-inch while the .22 long rifle cartridge rim diameter averages about 0.271-inch. The difference of 0.104-inch divided by 2 gives us 0.052- inch, the distance needed to move the firing pin hole in the breech block up toward the center of the new barrel’s chamber.

Before the original firing pin hole in the breech block was plugged, a new firing pin and bushing were made out of LaSalle fatigue-proof steel. This is a good, tough stock for firing pins as it needs no heat treatment and can be used as is when you’re finished. The new firing pin needed a main body diameter of 0.203-inch. The tip going through the breech block was to be 0.080-inch. The original pin’s main body measured roughly 0.187-inch. To get the desired 0.052-inch offset, the new firing pin would need this diameter increased to 0.203-inch. A pin turned to that diameter at a length of 11/4 inch will become the new firing pin. To offset the tip of the new firing pin by 0.052-inch, I placed a shim of the needed thickness between the 0.203 diameter pin and one of the jaws in a three-jaw lathe chuck. This caused the 0.203-inch diameter pin to run out 0.052-inch. The figure of 0.052-inch for the offset multiplied times 3 gives us the figure of 0.156. Add this to the diameter of the firing pin’s main body (.203), and we get 0.359-inch.

To create the shim, I made a bushing with an outside diameter of 0.359-inch and drilled out the center with a 13/64-bit in a drill chuck in the tailstock. Any easily-turned metal will serve as the basis for this shim. Center-drill the end of the part first, so the bit gets a straight start. We now have a bushing that can be cut into thirds, or at least sections wide enough to fit between one jaw and the future offset firing pin. With a one-third section of the bushing between one jaw and the firing pin, turn the end of this pin down to 0.080-inch, for a length of 0.100-inch. Use at least a 0.015-inch radius on the tip of your cutting tool so it will cut a like radius where the tip meets the main body of the pin. A radius will add strength to this junction, as opposed to a sharp shoulder, which is more prone to breakage.

Another pin measuring 0.203-inch in diameter will be the bushing that fits into the front of the breech block. Face one end of this pin so that it is flat. This pin should run out 0.052-inch, so the shim will be needed here as well. Insert a drill chuck in the tailstock of the lathe and center drill the end of the pin with a small (#11) bell-type center bit with the shim in place and the pin running out 0.052-inch. Remove the center drill, replace it with a #45 wire gauge drill bit, and drill the pin all the way through. This pin will become the bushing for the new firing pin hole in the breech block.

American Gunsmith, Gunsmithing the Rifle

American Gunsmith, Gunsmithing the Rifle

When the front sight dovetail is cut into the barrel, it should be made with the cutters running no faster than 300 rpm.

The original hole for the firing pin in the breech block measured 0.192-inch with a gauge pin. This hole was then reamed to 0.2031-inch with a 13/64-diameter reamer. Reamers almost always follow a hole previously drilled but if your setup it true, the new hole could just as easily be cut with a 13/64-inch drill bit. This hole was cut completely through the breech block and out the front face. The extra pin that was made to a diameter of 0.203-inch with the offset #45 drilled hole is going to be the bushing for the front of the breech bolt face. This pin was then cut to a length of 1/8-inch and the cut- off end faced off square. Make sure the offset firing pin easily slides through the offset hole in the bushing. If it doesn’t, polish it until it will. Using the new firing pin to help guide the bushing, dry fit the bushing so that the 0.052 offset firing pin hole is in the top dead center position in the front of the breech bolt. Silver solder this bushing in place. Once the breech bolt has cooled, the firing pin hole in the breech bolt can be cleaned out by running a 13/64-inch drill bit, ground to cut flat bottom, through it. Dress the face of the breech bolt flat with a smooth cut file, taking care to not remove any metal from the face of the bolt. Just clean up the new bushing until it blends in with the breech bolt face.

Test the new firing pin for fit by placing it inside the hole in the breech block. It should slide back and forth freely, with no binding. If it sticks at any point, color it with layout dye or a felt tip black marker. Try the fit again and see where the dye rubbed off. These spots are causing the sticking and should be removed with emery paper or needle files. Polish these areas until the firing pin moves back and forth smoothly.

The old firing pin was held in place with a cross pin going through the breech bolt and a notch in the firing pin keeping the pin from going out the back of the breech bolt. The new pin will be held in place in the same manner. Once again, color the main body of the firing pin. Insert the new firing pin into the breech bolt, then move the cross pin into the breech bolt until it rests against the side of the firing pin. Slide the firing pin back and forth so the cross pin rubs the dye off the area of contact. Remove the cross pin, insert it into the other side, and mark the pin in the same manner. This will reveal how much material needs to be removed from the main body to allow free travel. File, grind, or mill this relief cut into the new firing pin. Bear in mind that there may be some slight adjustments to the length and depth of this retaining pin cut to allow for the firing pin’s travel. The firing pin tip could probably be left round and function well enough to ignite a rimfire primer.

Once the new firing pin was made for this rifle, and the proper protrusion length determined, a blunt chisel point common to most .22 rimfire firing pins, was filed to shape. The rear of the firing pin was then contoured to the general radius of the rear of the breech block. Making the firing pin longer at both ends gives you the option of adjusting lengths when this stage is reached.

With the firing pin where I thought it should be, the gun was reassembled for testing. I generally keep a box of .22 rimfire blanks on hand just for that purpose. Popping a few blanks revealed that the firing pin needed to be shortened at the 0.080-inch diameter end.

After the pin was properly fitted, the rifle was completely disassembled once more. The checkering on the hammer spur was recut and pointed up to give it a nonslip surface. The receiver, along with all its parts, were soaked in rust and blueing remover so that visually checking the metal parts would reveal any rust pits, scratches or dents hidden by the blueing. Actually, there wasn’t much blueing left on these parts. It was more of a brown film—patina if you are a collector; rust if you are a buyer. All the parts were then hand-polished in stages until a finish of 320 grit was achieved. The parts were then buffed with a green Scotch Brite pad like those used to clean pots and pans. This will reveal any sanding scratches left behind in the finishing process.

This project started quite awhile ago and, in many ways, is like the story about the cobbler’s children never getting any shoes made for them. Business and other projects keep getting in the way. The planned ending is for the receiver to be color case-hardened after a AAA American walnut stock and forearm have been fitted, finished and then checkered. All metal parts except for the screws will be slow rust blued. The screws will receive the nitre or fired blueing process.