I could swear I'd seen one. Similar to an annular cutter or a plug cutter for wood.

I need to cut a cylindrical projection .200" diameter on a carrier dog (it was worn undersize and I welded it up; I can file it or try to hold it down on the rotary table or the lathe or use a boring head or fly cutter probably, but I'd have other uses for this). The projected cylinder would be like a trunnion on Beretta shotgun action. Needs to cut a cylinder in the center but mill flat around it.

Thanks, Steve

They are referred to as a hollow mill

Also you can use a boring head and a boring bar to do the same thing on such a low height stud

J Wisner

drill a hole in any piece of drill rod and hand file the cutting flutes. should take about 5 min tops. no need to harden . if you want to get carried away, you can drill all the way through and then back bore with a bigger drill bit within .050" of the cutting end. add 45 seconds to the above time estimate.

Thanks, both!

you will be amazed at the precision cutting tools you can make with a lathe, torch and file. a little dykem or black sharpie helps you know where you're going with a file.

I just made a thread mill out of O1 and it cut perfect threads. You need to remember that high carbon drill rod (O1) will need a much slower cutting speed than HSS. Just cut the RPM in half and with a little cutting oil you will be fine.

I usually file the secondary clearance angle within .020" or less and then harden and temper. then stone (or diamond lap) the final cutting angle. never made a tool that didn't cut as expected. I'm still using cutting tools I made 30 years ago in gunsmithing school.

My buddy uses a hollow core end mill to cut the bolt knobs off of rem 700 handles so he can install "target" knobs. I'll get the numbers. Probably came from Travers.

James, Thanks! I'd like to try that out. Have made a couple of taps for oddball threads and a chambering/reloading die reamers out of O-1 and they did work pretty well cutting slow like you say. And I've seen shop-built D bit cutters and multi-flute side cutting tools. But I'm afraid I can't imagine the geometry for the cutting edge and relief for a flat bottom cutting tool. Is it 4 cutting edges with shallow relief angle straight back from the cutting edge for each cutting flute?

Rich, appreciate the link.

i love that I am not the only one that loves o1 for making tools ....

oh, interesting to note, if you water quench o1, it's harder than woodpecker lips ... and brittle!! but of you need something stupid hard, this will work, in a pinch

The proper name for what you want is called an annular cutter

quote:

Originally posted by skl1:
I could swear I'd seen one. Similar to an annular cutter or a plug cutter for wood.

I need to cut a cylindrical projection .200" diameter on a carrier dog (it was worn undersize and I welded it up; I can file it or try to hold it down on the rotary table or the lathe or use a boring head or fly cutter probably, but I'd have other uses for this). The projected cylinder would be like a trunnion on Beretta shotgun action. Needs to cut a cylinder in the center but mill flat around it.

Thanks, Steve

Inquiring minds want to know, what is a "cylindrical Projection" and a "carrier dog"??

http://homesteadparts.com/shop.../rem12carrierdog.jpg

Jim, I hope the link to the picture on Homestead Parts's website works. It's a carrier dog on a Remington Model 12 pump 22. The "cylindrical projection" engages under the lifter and rides a ramp to time the lifting up of the next cartridge to the bolt face and into the chamber.

Steve

quote:

Originally posted by J Wisner:
Also you can use a boring head and a boring bar to do the same thing on such a low height stud

+1 This is how I would do it. I've made sako style extractors like this.

I use a carbide end mill to cut a hole in the end of a high speed steel end mill. Use rotary table and make the hole any size I want.

quote:

Originally posted by gwahir:
I use a carbide end mill to cut a hole in the end of a high speed steel end mill. Use rotary table and make the hole any size I want.

Explain please!

Carbide will cut HSS!

quote:

Originally posted by gwahir:
Carbide will cut HSS!

Yes. but why in this case?

Jim,

I think he's saying that to make the hollow mill cutter, he's basically "drilling" the center of the HSS endmill (to allow a "cylindrical projection") with the carbide endmill. If he needs a bigger hole/cylinder, then he puts the HSS endmill in the rotary table and by offsetting the carbide endmill, he gets a bigger hole in his new hollow mill.

gwahir, let me know if I got it wrong.

quote:

Originally posted by skl1:
Jim,

I think he's saying that to make the hollow mill cutter, he's basically "drilling" the center of the HSS endmill (to allow a "cylindrical projection") with the carbide endmill. If he needs a bigger hole/cylinder, then he puts the HSS endmill in the rotary table and by offsetting the carbide endmill, he gets a bigger hole in his new hollow mill.

gwahir, let me know if I got it wrong.

That's how I read it too. This would give you a hollow end mill that would allow you to make a "cylindrical projection" of a non-standard diameter. Especially handy if you had a number of these projections to machine.

I can't see how the H you will get it to cut steel. Maybe you wouldn't need any relief on the hollow part.

quote:

Originally posted by Jim Kobe:
I can't see how the H you will get it to cut steel. Maybe you wouldn't need any relief on the hollow part.

Good point. With no relief inside the center hole, the walls would be rubbing on the projection as the cutter fed down. Galling might be a problem. I wonder what sort of finish it's producing?

maybe dumb question. IF you have a rotating table can't you just chuck up an old end mill and rotate the part off center

oups I see gwahir post

Well, I made this tool out of 01 last weekend. Worked great! Thanks for the idea, James.

Of course I dropped the part under the workbench behind 40 bags of lead shot, so...