.0625 Wall thickness .
Receiver viewed from right side. The top of the receiver has been reduces glare along the receiver's sight plane. Be sure to use quality matted. In addition to Improving the pistol's appearance, this step steel of known analysis for the entire receiver assembly.
chamber section is turned to the inside diameter of the slide, and cut to the proper thickness. The collar will be silver soldered and pinned in place eventually, but don't do it yet. The finished weight of the complete slide must be between six and eight ounces to assure proper operation, and you may have to add or remove weight from the slide assembly.
The breech block (or bolt) is made from a piece of one inch diameter round stock 2.600 inches in length. Use good quality, tough steel for it. An automobile axle is quite suitable.
Turn the rod's forward end to the inside diameter of the slide body, and 1.700 inches long. Its rear end is left the full one inch in diameter, but the top and bottom are ground and filed to the same radius as the forward end, leaving an "ear" on each side of the breech. These ears are the same diameter as the outside of the receiver. Their size should be .500 inch wide by .700 inch long, centered on lines at the three and nine o'clock positions. Checker or groove the ears' outer surfaces, both for appearance and to provide an easily gripped surface, since the ears are the means by which the slide is manually retracted.
A counterbore is drilled into the face of the breech block. Make it .050 inch deep, and .006 inch to .010 inch larger in diameter than the maximum rim diameter of the cartridge this particular slide is made to accommodate. For the center fire cartridges, drill a hole for the firing pin in the exact center of the counterbore. On the rimfire model, the hole must be drilled just inside the rim of the counterbore, preferably in the twelve o'clock position. Drill from the counterbored end with a 1/16 (.0625 inch) bit to a depth of at least .400 inch. Do this drilling operation with the breech block chucked in a lathe if possible, with the drill held in the tail stock chuck. After the small hole is drilled from the bolt face end, the breech block is reversed in the chuck, and drilled from the rear end with a number six drilltoadepthof2.350 inches. Ifthe drilling is done slowly with a properly sharpened drill and sufficient lubricant used, both holes will line up on the center line. Polish the inside of this hole to make it as smooth as possible, since the firing pin fits into it. If this hole is not properly finished, the firing pin will bind. Fine sandpaper or emery cloth wrapped around a small rod and held against the walls of this opening while the breech block turns in the lathe is a reasonably good method of polishing. You may have to stay with it a long time.
A 1/8 inch hole is bored in the bolt face just inside its outer diameter, 30 degrees left of top center (in the eleven o'clock position). Drill this hole 1.200 inches deep and parallel to the body of the breech block. .600 inch back from the bolt face and at a right angle to the hole just drilled, bore a hole .250 inch deep directly into the bolt body. A slot for the extractor is now filed from this hole forward, using the lengthwise hole as part of the slot. The
Above: top view of the receiver. Note the fixed sights on top of it. These sights are home-made, though commercial sights could be substituted If available.
Below: bottom view of the receiver, showing front and rear mounting brackets.
To clear magazine lips
To clear magazine lips slot should be just over 1/8 inch square. The extractor will rest in the slot, along with a/etaining lug in the last hole (.250 inch) drilled, and a tension spring and retainer positioned in the remaining portion (or .600 inch) of the lengthwise hole.
Cut a slot for the hammer out of the rear end of the breech block, centered on the top and bottom center line. Its dimensions are .260 inch wide (to clear the .250 inch thickness of the hammer) and .550 inch deep, with flat sides and a square bottom.
A trough or slot is cleared from the breech block's front bottom side, to fit over the lips of the magazine when the gun is assembled. Leave a raised portion in the bottom of this slot to ride between the magazine lips, serving to strip a cartridge from the clip and push it into the chamber. The easiest way to form this slot, if you don't have access to a milling machine, is to mark its outlines on the breech block's forward end and the bottom side, and drill interconnecting holes just inside the outline. Remove the bulk of the steel and finish with files and chisels. The dimensions of this opening are different for each caliber and are shown in the drawings.
A small recess within this raised portion allows the upper end of the disconnector leg to ride through the frame opening. This recess, and the top of the disconnector leg will need to be hand fitted during assembling and testing. It is this recess that permits the trigger bar to engage the sear, and pull it forward when the trigger is pulled, firing the gun. Basic dimensions for this recess are provided in the breech block diagrams.
The bottom lip of the counterbored bolt face is filed away until the cartridge head can slide freely upward into the counterbore.
As shown in the illustrations, the rear end of the breech block is sloped with a slightly concave shape. This should be ground and filed almost to size and left unfinished until put together. At that time, the receiver, slide body, and breech block are finished all at once, assuring a smooth, well-fitted assembly.
Turn a firing pin to the dimensions shown in the drawing. Drill rod is suitable for making the pin. If no drill rod is available, find a discarded automobile shock absorber, and use its piston rod. The firing pin should be no longer than the distance from the bottom of the hammer slot to the bolt face. This means that when the hammer is down, the firing pin is just flush with or slightly below the surface of the counterbored bolt face. Be certain that the firing pin fits precisely in this respect, since it is only then possible to safely carry the pistol with a loaded chamber with its hammer down. If the firing pin is even slightly too long, a blow on the hammer could cause the gun to fire. When the pin is properly fitted, though, the pistol can be dropped, thrown, or hammered without danger of it firing.
Above: lop view of the finished slide assembly with home-built recoil spring In place.
Below: bottom view of the slide assembly. The cut-out portion Is for magazine clearance; the raised portion in Its center strips cartridges from the magazine Into the chamber.
Bore a 1/8 inch hole just forward of the hammer slot for a firing pin retainer as shown in the diagram. Place a close-fitting rod inside the firing pin hole prior to this step. The rod will guide the drill and prevent it from wandering toward the unsupported side, as it will if the firing pin hole is left unplugged. After drilling the hole, cut a corresponding slot in the side of the firing pin to accommodate the retaining pin that keeps it in place.
You will need a coil spring small enough to just fit into the firing pin hole without binding; the spring's inside diameter must fit over the body of the firing pin. The spring serves both to retract the firing pin after firing, and also to prevent it from jumping forward as the slide slams shut, perhaps firing the gun without pulling the trigger. The finished spring should be about 1V4 inches long and have 24 to 30 coils of wire, .022 inch to .026 inch in diameter. Start with a longer spring than is required, and cut off a bit of it at a time until it performs correctly.
Saw and file the extractor to shape from 1/8 inch flat stock. A strip cut from an annealed automobile leaf spring works well for this piece. A small coil spring, .700 inch long, that fits freely inside the lengthwise hole at the end of the extractor slot is used behind a follower turned from drill rod (a broken 1/8 inch drill stem is just right). A flat is ground on one side of the follower, providing spring tension on the extractor and also retaining it in place.
Weigh all of the parts together that go into the slide assembly. Again, they should weigh between six and eight ounces. If they are within these weights, the bushing at the forward end and the breech block at the rear end can be silver-soldered in place. Use pins or screws in conjunction with the silver solder if you do not trust silver-soldered joints completely. As I've said before, I do not.
Beginning directly behind the bushing and ending just forward of the breech block, cut a lengthwise slot .500 inch wide from the top and bottom sides of the slide body. The ejector clearance cut is now made, as is the magazine slot. This last slot is simply trimmed from the bottom of the slide, until the cut-out section and raised portion in the bottom of the breech block is fully exposed. Steel is also removed as needed from the upper right side to provide an unobstructed opening for the ejection port.
After the receiver assembly is completed, it can be fitted to the frame by spotting and filing. Make sure that the front and rear retainers fit properly as well as the joint between frame and receiver. When properly mated together, a hole for the takedown lever is drilled completely through both sides of the frame and the front receiver lug. As usual, drill first with a smaller drill and finish with a 5/16 or .3125 inch which will be the correct finished diameter.
Sweat, glue or silver-solder spacer blocks of steel on each side of the frame where the trigger pin and hammer axis pins are located. The steel shims reduce the inside
width to the same width (plus a small clearance) as the hammer and trigger. Again, I recommend silver-solder for this step. Place the steel spacers in their positions with the help of the paste-flux, with a spacer block of the same thickness as the hammer/trigger between them. The area is heated with an acetylene torch enough to flow the silver-solder, then allowed to cool. Remove the spacer blocks, and drill the holes for the hammer and trigger pins. Cut the slot in the lower rear of the magazine housing for positioning the combination magazine catch and hammer spring guide. Do not drill the grip screw hole until the grips are finished.
Put aside the frame-receiver assembly now until a barrel assembly is completed as described in the following chapter.
Adjust firing pin length according to Instructions on page 49
Coil spring As required for caliber used torn
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