cutting speeds

On or around Wed, 18 Oct 2006 10:44:56 +0100, Austin Shackles enlightened us thusly:
No?
Oh well, I'll have to hunt it meself then... :-)

Austin,
A chart is here:
lots of good stuff on that site which starts here:

That old Student still doing it's stuff?
AWEM

I've got an 80mm Indexa Seiki inserted (6 SEHW inserts) face mill that I've used on a Warco VMC and also on the Bridgy. On the VMC I couldn't really take any serious depth of cut on it as it would chatter too much because of the overall machine rigidity, but it did very nice job of finish surfacing taking a 0.005" cut at about 1000rpm and feeding quite slowly. Removing 3 of the 6 inserts made it chatter less on the VMC.
On the Bridgy I can cut about 0.040" deep in steel and feed the thing fairly quickly. The swarf comes off like little curly pig tails, speed would have been somewhere around 600rpm IIRC (not at home and can't look at the speed range plate!) In Aluminium I run the spindle at about 1100rpm and crank the table about as fast as I can turn the handle. I can cut up to 0.080" deep in ally and it's no problem at all. What you do have to watch out for on these face mills though is that the swarf really does fly around everywhere off the cut.
I've also noticed that both the machine and cutter are happiest when the entire width of it is in the cut. When surfacing less then the width of the cutter it will get a bit of light chatter as it loads and unloads.
I recently put some new Kennametal coated inserts in it and the finish these give is absolutely superb. I'll try and dig a picture out if I can find it.
Peter

On or around Fri, 20 Oct 2006 09:26:17 +0100, "Andrew Mawson" enlightened us thusly:
excellent, I shall have a look.
yep. still noisy, still running. I solved the knock it had when I bought it - pulley on the driven end of the main belt loose on the shaft.
I've been fettling it gradually; hence the comment somewhere about switches for reversing...
I've even got the 3-jaw chuck to run (reasonably) centred, by dint of gripping a large old bearing shell on the outside of the jaws and running a carbide-tipped boring tool down it.
needs a bigger motor, though. anyone got a 2.5HP single-phase 1400-odd rpm motor going spare/cheap? Can swap it for a 1.5HP...

On or around 20 Oct 2006 02:32:05 -0700, "Peter Neill" enlightened us thusly:
yeah, kennametal seem quite good stuff. I've got their inserts for a lathe tool this time.
might have to look at getting a better milling cutter - this is a fairly-crap one that came with the machine - at the price, it's not going to be even middle-notch stuff. Main problem is that it's got brazed-on cutting doofrits, not replaceable, and some of them are chipped.

1400-odd rpm Sorry my biggest unused single phase is only 1 hp. Got all the bit to make a big rotary phase converter though if you want to run 3 phase including a 15KW idler motor and 240 to 415 auto-transformer & start caps.
AWEM

On or around Fri, 20 Oct 2006 18:08:21 +0100, "Andrew Mawson" enlightened us thusly:
I had been considering that - but from looking into it, it's liable to be more hassle and expense than just buying a single-phase motor. Granted, the single-phase motors are not so good technically, but for the sort of use the machine gets efficiency is not super-important.
I had also though about a 3-phase alternator and making up a generator set to generate me own 3-phase power, but I don't really need enough of it to be worth it. I know a local sawmill where they run a biggish generator (on red diesel) which is way cheaper than getting 3-phase power put in - but they run BIG machines.

start Granted, the generator set I'm surprised at that as I worked out the figures for my 100kw generator that I use fo the induction furnace, and it comes out more expensive than grid bought stuff and that's with no allowance for maintenance and wear and tear. It's just that they want a fortune to run a 150amp 3phase service in!
AWEM

On or around Sat, 21 Oct 2006 10:48:32 +0100, "Andrew Mawson" enlightened us thusly:
I think that's the point. the cost of buying secondhand gensets is much lower than getting the board to put a fat 3-phase supply in, unless you live beside the substation.