INDEXING HEAD
Now that this is done it is time to cut the land grooves in the button. Set up the indexing fixture on the
milling machine. You will need some way to set an angle to the indexing head.
They have special angle plates for this purpose. If your indexing head is set up for collect or drill chuck,
you can make a short piece of drill rod, drill. Then ream for the No. 5 taper pin reamer, and solder the
button in place. When cool chuck the drill rod and button.
The angle is set the same way on the milling machine as it was done on the lathe. Your 30-caliber button
with 1 in 12 twist, the angle is 4 degree and 35 minutes, or referring to the Taper per inch chart it would
be .0795. Set this angle of taper on the indexing head and it is completed.
Put your arbor with the 1/8-inch wide 60-degree diamond wheel in the collet of the mill. Now this is tricky.
You will have to lower the grinding wheel to where it just touches the large diameter of the button.
One half of the button is .555; add .062, which is half of 1/8, which is .218. Now set up the dial indicator
and run down the diamond wheel to .218.
If everything was done right, it will be on the exact center. Turn on the mill at the highest speed it will run,
and the mist coolant. Bring the diamond wheel to the edge of the carbide to where it just touches. Set it
for a .005 cut, and feed it across very slow.
Keep track of how many thousands that you have fed in on the first groove. The only thing that you have
to do now is to figure how many lands and grooves you want and how wide the grooves should be.
SWEATING BUTTON TO PULL ROD
After all the grooves are cut, the button is ready to sweat to the rod. The rod is .281 in dia. and is drill
rod. The drill rod should be chucked in the lathe, centered, drilled to depth with a drill slightly larger than
the small end of the carbide. It is then reamed with the No. 5 taper reamer.
While still in the lathe, coat the inside of the finished reamed hole with silver solder paste; stick the
button in the reamed hole. Put the lathe in back gear and start up. Take the torch and with a cool flame,
heat the button, shank, and rod until the silver solder melts.
Hold the button for a few seconds so the entire inside surface is tinned, and turn off the lathe while
pressing the button in hard in the reamed hole. Let it cool slowly.
The button is now attached to the pull rod. The next step is to cut the rod to the right length, turn, and
thread the rod to a 1/4 x 20 thread. This will be attached to the rifling head. This end should be hardened
and brought back to a light blue (700 degrees). If you fail to do this, the threaded end will break the first
time you use it.