I've done a few of these now and have cut a few chambers with them, they work amazingly well, the chambers they make look as good as those cut with factory reamers. So here goes, it is really easy, takes me about 2 hours and I am slow with very little equipment.
Start with about a 6 inch piece of Water Hard drill rod, this is steel you harden by getting it red hot and dropping it in water as opposed to Oil Hard that you drop in oil to harden. Oil hard may work good too, I have just never used it.
Drill some center holes in the end of the bar and set it between centers in your lathe. I don't have a face plate but I let the dog run on the chuck jaw and it works fine. With some type of measuring device, offset your tailstock to obtain half the proper case taper on your work piece. This is an 17 AH so I need a taper over the length of the body of .011 inch, so I set the offset to get .0055 over about 1.060 inches.
Now turn the body taper on the drill rod until you have the proper diameter at the sholder and at the base.
Now locate where you want the sholder to be, but first take the offset out of the tail stock. Set the sholder angle in on the compound this one is 30 Degrees, but you can make it any thing you like. Turn the sholder on the rod, leave a neck that is about .005 to .010 smaller than the bore, don't know why, I just do it. You will need to ream the neck after you cut the chamber.
When everything is wonderful, part off the reamer in work.
Now the tough part. I use a milling attachment to remove just over half the the diameter of the reamer, these only work with a tapered case, you cannot cut a straight hole with one, that is why we don't cut the neck now. I leave a small bar down the middle of the reamer to thicken it up and make it stronger, this works well for me, if you are using a grinder to take off the metal you can't do this. I remove metal until it is half as thick as it started minus about .002 inches to make sure I take off more than half.
Now get it fairly bright red with a propane tourch, it takes a while to get the whole thing bright red, then into the cold water, and it is really hard. A light stone on the edge making sure not to round it off and you are set. These reamers cut both directions, so when one side is dull just turn the lathe the other way and cut some more. Larry
