keyhole cutters?? 38/357

[decoy91288]

I am new to metal work and have recently purchased a Taig lathe. I am in process of making lots of little slivers of metal while figuring how the thing cuts etc.

Since the lathe was there and I needed a new shell holder for reloading 38/357 I decided doing something other than making sharf would be a good idea. I now have a beautiful brass shell holder that will not hold a shell 'cause I could not bring myself to grind a new end mill to undercut the slot for the rim.

Are such cutters commercially available?? or do I just grind it and smile? Can a cutter like I need be ground from drill rod then tempered??

Since the piece needs to be undercut, what is the suggested way to make the cutter - turn down a drill rod?? Would the flutes be cut in before grinding down - seems to me this is likely.

Since I am asking questions based on ignorance - I read some plans that called for "grinding" a surface after machining. He indicated it was for appearances. Does the author mean sand and polish?? or what if not that?

Feel free to explain the most common knowledge items.

thanks,

Craig

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Craig

[wwheelock]

First I will have to say I'm no expert as I have only been attempting to learn machining for about 8 months now. You should be able to purchase a metal slitting saw and mount it on an arbor and do your undercutting. You could also use a side milling cutter mounted in the same way to do the job. A T slot cutter would also work and that could be held by the lathe chuck. Another tool that you might be able to easily find is a dremel HSS cutter that looks very similar to a woodruff key seat cutter. I'm assuming that you are using a milling attachment mounted on the cross-slide to hold the shell holder? Or it could also be held on an angle plate mounted to the cross-slide.

A couple of sources for milling cutters are J&L industrial and Enco. Both have web sites and I believe they are www.jlindustrial.com (http://www.jlindustrial.com) and www.encotools.com. (http://www.encotools.com.)

Making a cutter out of drill rod is possible, but keep in mind that drill rod is high carbon steel. After shaping the cutter you would have to heat it to a bright orange and quench in oil to harden in the case of oil hardening drill rod. To see if the hardening was sucessful run a file across the piece and see if it will just glide across without trying to cut. If this is the case your hardening worked! Now if you use the hard tool it must be kept cool as high carbon steel will begin to soften at as little as 400 degrees. That's a big disadvantage of using tools made from high carbon steel and the reason why most tools are made from High Speed Steel, as HSS doesn't begin to soften until brought to red hot.

A couple of books I would recommend to a beginner are THE AMATEUR'S LATHE by L.H. Sparey and THE AMATEUR'S WORKSHOP by Ian Bradley. Both books are available from Gunsmith supplier Brownell's, www.brownells.com (http://www.brownells.com)

I hope I was of some help.

Bill Wheelock

[charlie coghill]

Hi Craig.
You could set the shell holder stock in the lathe.counter bore for the diameter of the case and bevel it as the RCBS shell houlders are than grind a lathe tool bit and cut a recess for the shell rim at the bottom of the counter bore. Then with a end mill cut into the recess and thru to the counter bore.
Hope this helps.

[SGW]

If you don't have it already, get a copy of the MSC catalog. It's mind-boggling, and you will see all kinds of cutters in it you never imagined existed.

(See www.mscdirect.com. (http://www.mscdirect.com.) The catalog weighs about 12 pounds and is free!)

[John Lawson]

Craig,
A shellholder must be cut from a hardenable grade of tool steel and properly hardened after it is made. The pressures of pulling a tight case out of a die that is running unlubricated will pull your beautiful brass shellholder to pieces or stretch it into uselessness.
Actually, you could make one from drill rod and harden it by plunging into a layer of oil on top of a half jar of water and salt.
The cutter would have to be cut to the proper diameter and thickness by using your toolpost grinder.
In that you don't have a toolpost grinder, you would have to begin by making a mount base and clamp for a Dremel tool that would attach to your lathe. I recently made such a device for my C5 Emco lathe. It will take a while to cut down a large keyway cutter to proper dimensions, and you need to protect the lathe with pieces of aluminum foil while grinding.
I have several extra .38/.357 shellholders because I have all progressive presses but one.
Send me your address and I will mail you one of my extra ones, since I will never use it again.
For other neat things to make for lyour lathe, visit my web site:
http://groups.yahoo.com(group)emcocompact5users