Fig. 5-15 TANG AND STOCK BOLT Views of the tang and stock bolt.
Fig. 5-16 STOCK AND FOREARM
Exact size outline drawing of the stock and forearm of the F.D.H. CH1COPEE
C.F. rifle shown in this chapter.
As described in the text, this photo shows the drillpress setup to grind the radius surface on the rear of the breech block sides.
This shows the drillpress set-up to grind the support shoulders. See text for further details.
Instructions and Sequence of Operations for Making the F.D.H. CHICOPEE C.F. Action
As you may already have noticed if you have examined the drawings, we have not provided you with every specification or all dimensions on most of the parts. We have done this purposely. If, for example, in Fig. 5-10 we had supplied all of the dimensions needed to make the hammer drawing a true mechanical drawing, it would have covered an entire page and one look at it and you surely would have thrown up your hands and given up on the entire project. Making such a drawing would have been very difficult, but far less difficult than it would be for you to make the hammer according to those dimensions. Instead, what we have done is to give only the most critical dimensions and the exact sized drawing of the parts so that you can shape each part to your own liking. In the cutting out and making of many of the parts, such as the hammer, we suggest you put masking tape on the piece of steel from which the hammer is to be made, and using carbon paper trace the outline of the hammer on it, spot the hammer pin hole and drill it and then rough saw and file the hammer to shape. Leave a little extra metal on it for the final fitting. If you do not like the shape of the spur on our hammer, then go ahead and shape it to your own fancy. Making the hammer and other parts in this way is far easier than making it according to a set of figures. And, if in the making of a part, you find that you have removed a bit more metal than our drawing or dimensions show, or you have a hole drilled a few thousandths off, it probably won't matter as you can compensate for it in the making and fitting of another part to it. For example, the hammer safety lock lever, once you understand what its function is and how it has to work it does not have to be made exactly as shown in the drawings or engaged with the locking lever and hammer in the exact place as we did. The entire design of the CHICOPEE action is such that there are few vital specifications to follow.
THE RECEIVER RING (see Fig. 5-5)
Make this part from cold rolled steel. You can use a standard tap to thread it if you have the means of starting the tap in correct alignment with the hole. The preferred method is to cut the threads in a lathe setup and in this case we would suggest going to 16 or 18 threads per inch. You can fit the barrel to this part at the same time. It is important that the unthreaded part of the barrel shank be a close fit in the receiver ring. A threaded portion 3/4" long is ample. Tighten the barrel in the receiver ring and turn off the breech end flush with the receiver ring. After fitting the barrel set it aside until it is time for the final fitting and chambering. If you are going to silver braze the receiver sides to the receiver ring (Fig. 5-5) use a 1/8" Woodruff keyway cutter to cut the grooves in the receiver ring, and also use it to cut the grooves in the receiver sides. The four small holes in each of the grooves in the receiver ring serve to hold short pieces of silver-solder wire during the silver brazing operaton. They need be only about 7/32" deep to hold 3/16" pieces of wire and of a diameter a bit larger than the wire you have. If you plan to steel weld these parts together prepare the receiver ring and sides as shown in Fig. 5-6. Steel welding with oxy-actylene torch or with an electric arc welder is the stronger method for joining these parts.
RECEIVER SIDES (see Fig. 5-5)
Use 3/16" thickness cold rolled flat stock. This steel usually has a hard scale surface that is rather unsightly and often pitted and we suggest that it be removed. This can be done quite well with a belt sander and emery cloth belt or with a disc sander. The best method, however, is with a surface grinder. If the parts are to be silver brazed together machine the tongue and grooves to match those in the receiver ring and shape them to the outlines as shown. The fit of the tongue and groove cuts in the receiver ring and receiver sides should be an easy sliding fit requiring little hand pressure to fit the pieces togther, with just enough looseness to permit silver-solder to flow throughout the entire area. After the tongue and grooves have been cut into the sides, shape both sides alike. If the parts are to be steel welded together, merely bevel off the cor ners of the joint to be welded as shown in the front end view of Fig. 5-6. Do not drill any holes in either side at this time. Your next job is to make the breech block sides.
BREECH BLOCK SIDES (see Fig. 5-7)
Use 1/4" thick cold rolled steel with scale removed. Two identical sides are required. We suggest you make a carbon tracing of the breech block side drawing on a piece of cardboard, cut that out for a pattern and then use it to cut out one side from the piece of steel. Now carefully spot and drill the hammer pin hole and the hinge pin hole, 7/64" for the hammer pin and 11/64" for the hinge pin. Clamp this drilled and roughly cut side to another piece of steel, drill it through the holes in the one side already drilled and pin the two together with snug fitting pins. You can use a piece cut off the drills used for these pins. These two holes are now your master guide holes for all the remaining operations on the breech block sides as these sides must be identical. Saw out the second piece to match the first. Mark each side in some way to indicate right and left sides.
Now you are confronted with two operations that are critical and must be done right. The First one is to file or machine the top of the breech block extension and the face (standing breech) of the breech block level and square to each other. The second critical operation is to grind or machine the radial surface on the rear of the two sides. This is quite easily done in a simple drill press setup (Fig. 5-17), especially so if your drill press is fitted with an Atlas compound feed accessory. Take a smooth and level board (a 1x4 one foot long will do) and drill a hole centered and 3" from one end of it into which you drive the guide pin used in the hinge pin hole. You should clamp this board to the drill press table or in the compound feed accessory and place the breech block sides on the pin so that the rear end of the sides project over the end of the board. Use a 1" wide by 4" diameter fine grit grinding wheel mounted on a short arbor and chucked in the drill press. Adjust things so that the rear of the breech block sides can just contact the surface of the grinding wheel. With the wheel turning at its correct speed and with one hand on the breech block sides to swing them in short arcs against the wheel, slowly feed the table towards the wheel. Grind until you have a smooth surface or until you have obtained the approximate radius of 3.82" as shown in Fig. 5-7. A similar setup can be used to grind the concave surfaces on the breech block support shoulders, this will be described later.
FIRING PIN BLOCK ASSEMBLY (see Figs. 5-1, 5-2 & 5-8)
Use 1/4" cold rolled steel to make the block and tool steel for the face. Making and partially fitting the firing pin block along with the 1/8" thick breech face is the next suggested operation. Use a 6x48 Weaver scope mount screw to attach the breech face to the firing pin block and use a No. 6 fillister head screw, 32, 40 or 48 thread, to hold the block in place and the breech block halves together. The hole for this screw should be drilled low so that it will be hidden by the receiver sides. Do not do any drilling for the firing pin hole at this time or to finish the top of this assembly. Make sure the breech block sides are perfectly aligned before and during the drilling and tapping of the firing pin block retainer screw hole.
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