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+--- Thread: Cutting Speed and RPM on the Lathe and Mill (/thread-1755.html)
RE: Cutting Speed and RPM on the Lathe and Mill - chucketn - 10-01-2013
Well done, Tom. I wrote down your formulas and will print a chart to hang in my shop.
Chuck
RE: Cutting Speed and RPM on the Lathe and Mill - stevec - 10-01-2013
(10-01-2013, 10:26 AM)TomG Wrote: at some point eyes start to glaze over.I'm gonna put masking tape over the little camera at the top of my laptop's screen.
RE: Cutting Speed and RPM on the Lathe and Mill - TomG - 10-01-2013
There's more truth to that than you might imagine Steve.
RE: Cutting Speed and RPM on the Lathe and Mill - EdK - 10-01-2013
I was surprised you didn't break that 1/8" end mill climb milling.
My balls must be made of that sissy steel.
Ed
RE: Cutting Speed and RPM on the Lathe and Mill - TomG - 10-01-2013
I climb mill most of the time Ed. I'd rather have the end mill deflect away from the part than deflect into it and cut too deep. I break one once in a while, but not very often.
Tom
RE: Cutting Speed and RPM on the Lathe and Mill - f350ca - 10-01-2013
When I bought my mill I was so green I was afraid to go out in a field in case the cows would eat me. I cut the same as if i was using a router which I later discovered was climb milling. If you cut conventionally with a router the cuter tears the material causing splintering.
Oh this is bad so I read, as a result I tried conventional milling as much as possible. The surface finish sucked and the machine seamed to be hammering more than cutting.
With some experience comes confidence or absolute recklessness, like Tom I'm a back to being closet climb cutter.
RE: Cutting Speed and RPM on the Lathe and Mill - TomG - 10-01-2013
The reason conventional milling creates such a crappy finish is that the cutting edge drags on the work before enough pressure is produced for it to cut. When climb milling, as soon as the cutting edge hits the work, it's cutting, there's no dragging at all.
Tom
RE: Cutting Speed and RPM on the Lathe and Mill - Mayhem - 10-02-2013
So what's next Tom? Feed rates, depth of cut...
RE: Cutting Speed and RPM on the Lathe and Mill - TomG - 10-02-2013
Darren,
I'm debating the value of a feed rate video for the hobby machinist. I can show how to calculate the feed rate based on chip load and rpm, but most powered feeds on home machines are either variable or non-existent. I can't remember the last time I calculated a feed rate and then actually applied it. It's more "that sounds about right" or "the color of the chips is good".
Tom
RE: Cutting Speed and RPM on the Lathe and Mill - arvidj - 10-02-2013
Wow, an HP calculator and RPN to calculate RPM.
That is the second time this month I've seen an old HP.