QUOTE(Series9 @ Jan 4 2016, 10:36 AM)
Let's start with the basics.
What's the turning speed for various metals and other media?
How do I set the correct tool height?
Speed is dependent on diameter in addition to material. Surface feet per minute (at the tool) is the basis for selecting the correct rpm.
Generally, Aluminum under 1 1/2 inches can be spun at 1000 rpm or faster in most cases. Steel should be below 500 rpm for anything over 3/4 inch.
Carbide tools accept higher rpm than Cobalt steel. Cobalt tools can be run a little faster than High Speed Steel. Ie., they will operate at higher temperatures without ruining the tool.
Rule of thumb with steels, if the chips turn straw or amber color your at the max rpm. If they turn blue, slow the rpm down.
If a high speed steel tool turns color you are going too fast and ruining the cutting edge quickly.
Use a feed rate that gives a good surface appearance without taking too long to reach the other end. That will usually be around .005" per revolution, plus or minus, depending on the specific cut.
Depending on the equipment and the specific tool shape, you can run at cutting depths of .010" to .050". Deeper cuts will lose some accuracy, so best to leave a small cut for the last passes.
The crossfeed dial measures change in diameter, so turn the dial in 50 for a cutting depth of .025".
To lubricate aluminum, add 50% kerosene to your cutting oil.
You want some smoking of your cutting fluid to occur.
That usually indicates a good temperature for cutting.
The tool needs to be very close to the centerline, or just slightly above (< .060") in many cases.