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View Full Version : Speed for 1/16" Carbide Ball End Mill?



CCWKen
04-02-2007, 12:14 AM
There's no way I can get that kind of speed out of the mill so I'm thinking of mounting it in a TP grinder on the lathe. I'm making up a few snap and rivet setters so the lathe would be a better setup any way. (It will already be chucked.) I figured I could turn the chuck by hand and feed (DOC) with the compound but what speed should I wind this little bugger up to? The material is W-1 drill rod.

TIA

Willy
04-02-2007, 12:55 AM
Ken, my Machinist Toolbox calculator says 12,223 rpm, at a 0.0025 chip load per flute you are flying at about 122 ipm.
Those little suckers like lots of Rpm's, I've got some in .125 and I have a hard time utilizing them.
I should add those figures are for 4 flutes,2 flutes and your feed rate will be halved.

Mcgyver
04-02-2007, 07:03 AM
you'll bust cutters with 2.5 thou per chip for a 1/16 cutter, divide by ten imo. you can do this at 2k just fine, provided you reduce the feed rate as well. production like that maybe not, but fine for doing a couple of rivet snaps

DR
04-02-2007, 08:09 AM
Turning the chuck by hand will be very tricky with an end mill that small, one jerk or uneven movement and good bye end mill.

Why not use a grinding point instead of an end mill? Then you can run the lathe spindle at slow speed.

CCWKen
04-02-2007, 01:52 PM
Thanks guys. I think DR has me talked out of that idea. I'd hate to see part of an $18 end mill go flying. I had thought about using a carbide bur in a rounded tree form but didn't know the size of the point. I tried a small stone but it didn't last long enough to get around one pass.

The double cut burs might be a better way to go. I'll have to order that. Thanks for the help.

BobWarfield
04-02-2007, 02:41 PM
This can be done with the endmill. ME Consultant Pro suggests 15 IPM with a 20,000 rpm (Dremel) spindle speed for a 2 flute in aluminum. Steel will be a different story, but you didn't mention your material. I would keep depth of cut to the mill diameter with these tiny little mills.

I've had good success with these little end mills in my Dremel powered CNC mini-router:

http://www.thewarfields.com/cnccookbook/img/MiniRouter/EZClamp/P3243879.JPG

For getting to the right feed, I like to convert IPM to "handwheel turns per second". It's very easy to count off and get pretty close to the speed you'd like to feed.

BTW, 1/16" carbide end mills can be had much cheaper on eBay and their fine cutters. I think I paid $3 to $4 apiece for mine. Sometimes less.

Best,

BW

CCWKen
04-02-2007, 07:34 PM
"Steel will be a different story, but you didn't mention your material."

I believe I did. As the last sentence in the original post said, it's W-1 drill rod. :eek:

Forgot: Do you also have a formula for converting IPM to chuck turns? ;)

Mcgyver
04-02-2007, 07:46 PM
Ken, I'm trying to remember where i'd see rivet head profiles, ie what radius for what OD. a snap dimple using 1/16 radius is for a very small rivet, right? or am i missing how you are doing this. I haven't done this exact job (making snaps) but I've thought about it - what about drilling a small pilot almost to depth then follow up with a hemisphere shaped d bit (could be made using Lautard's stepped approach to turning a radius) ?

japcas
04-02-2007, 07:57 PM
Ken, what is the fastest speed on your milling machine? If around 1200 to 1500 there is really no reason why you couldn't use the mill with that 1/16 diameter cutter. Like one of the others said, it might not be ideal for production but it will work for what you are doing provided you don't crowd the feed.

In the real world, you can't always go by what the charts call out. Not everybody has a 20000 rpm spindle, or even a 5000 rpm spindle but that doesn't mean that you can't use small tooling. I drilled a .013 diameter hole on my lathe with no problems and no broke drill bits and it has a top speed of 1200 rpms! I did use a sensitive drill chuck though. Yes, I could have use more rpms but I got the job done with the equipment I had here in my shop.

CCWKen
04-02-2007, 11:05 PM
Thanks guys. It may be a while for me to work up enough nerve to try it though. I just threw in a carbide bur with an order from Enco so I'll wait and try that first.

Mcgyver, one of rivet sets will be for small hollow rivets. (1/8x1/8") The setting punch has a small nipple in the center then tapers or flares into a rounded area like a donut footprint, so to speak. I've made a few free hand but not this small. For soft metal like copper, the flare needs to be pretty smooth or the rivet is crushed instead of spread and rolled. The others will be for setting snaps that also have hollow rivets.

BobWarfield
04-02-2007, 11:31 PM
Your drill rod wants about 1500 rpm like the gent said, but the feed rate is way slow with a 4 flute--0.704 IPM is what's coming up on ME Consultant. It wants to run a chipload of half a thousandth.

Not sure what you mean about chuck turns vs IPM, but I'll assume you wanted "handwheel turns". The dials on my mill give 100 thousandths per revolution. To get 0.704 a minute that's 704 thousandths / 100 thousandths per rpm or about 7 revolutions a minute. Each turn of the handwheel should therefore take 8 and a half seconds. Try turning between 8 and 9 "Mississippie's" or whatever you prefer for a cadence per revolution.

Best,

BW

Willy
04-05-2007, 09:33 AM
Ken, sorry I haven't been able to get back on this sooner but I have been rather busy the last couple of days.
Just a thought, but rather then trying to mill or grind the shape you need have you considered grinding a HSS bit to the profile that you need and using it as a form tool to get the profile you need as a rivet setter.
I use this technique often on W-1 to form a die if you will, and then harden it after it meets my requirements.