A b0

26

to D”, it is almost assured that the distance from “A to D” will not be correct as any smali measuring errors will “stack” or add up. If you measure from “A to B”, “A to C” and “A to D”, your measurements should be accurate.

FILE WORK

With Steel cut to the basie outline and shape of the firing pin, the remaining metal is removed with hand files (see Figurę 6). The work will go much morę ąuickly if you start with a coarse, or bastard cut file,

METAL REMOVAL

The first metal you will remove is from the center slot in the firing pin. Use a drill mounted in a drill press to help save time and effort. Carefully locate a series of over-lapping holes down the center linę of the slot. From the drawings, we know that the slot is .143” wide, so select a nine sixty-fourths (%«”) drill (.140” diameter) to drill out this slot leaving very little materiał to remove with a file. With only .003” differ-ence between the diameter of the drill and the finished width of the slot, locate the holes with great accuracy, using the magni-fying glass to properly place the center punch. If the holes are drilled off morę than .0015”, the slot will be out of spec.

After the holes are located and then drilled, use smali fiat and round files to flnish the slot out to the layout lines. When finished shaping the slot, double check to make surę that it is properly located.

Now, bring the part closer to its finał shape with the hacksaw. To avoid over-cutting, position the Steel stock in your vise so the top of the jaws serve as a guide, or “stop”, for the hacksaw (see Figurę 5).

FIGURĘ 5 - Rough -shape the part using drills and a hacksaw. Notę the "handle" on the right end.

FIGURĘ 6 - Use progessiuely fitier files to bring the rough part closer to its finał size.

instead of making the mistake many peo-ple do of using a file that is too fine. When you get to within .020” of your finished dimension, change to a finer cut file. This will give a smoother surface flnish, yet al-low metal removal with maximum speed and efficiency. Use your bench vise to hołd the workpiece and use the top of the jaws as both a “guide” and file stop to facilitate quick removal of Steel without over-cut-ting.

Filing Tips: Always use a file handle on the file shank to give a far better holding surface and much morę accurate work. Use both hands when filing; one hand on the handle and two or three fingers of the other hand positioned near the far end of the file to inerease control and help keep the file level. Alternating the direction of filing can also help keep the cutting surface level. Make one or two strokes from the lefl side of the part, then move to the other side of the vise and make an equal number of strokes from the right side. To check ifyou are cutting evenly or uniformly, coat the surface to be filed with Dykem. As you make a stroke with the file, you remove