/diy/ - Do It Yourself

>>1431637
In metal? You need to know the surface feet of the material youre cutting.
the formula is:

RPM = (SFM X 3.82)/DIA , diameter in inches

This works for either material turning (lathe) or tool turning (mill)
For a less stable machine, dont be afraid to go slower that this, like 3/4-half speed esp on mill.

For plunge you use chipload:

>IPR (inches per rev) = FPT (Feed per tooth per rev) * # Teeth or flutes

If the place you bought the drill recommends .015 chipload, you know your rpm using the first formula, and you know how many flutes you have (2 for a drill maybe more for an endmill) you can plug that into the formula and figure out your IPR (inches per Minute)

>IPM (inches per minute) = IPR (Inches per rev) x RPM =

You can use a chart like this to find IPR directly for your drills
http://www.morsecuttingtools.com/Technical%20Data/HSS%20&%20Cobalt%20Drill%20Speed_Feed.pdf
If you literally have no idea give the people that made your drill a call, theyll help

If you dont know your rpm, you should buy a lazer tachometer and at least get a rough idea, or youre going to have a bad time. As you can tell from the first formula, bigger = slower

Buy a Machinist handbook