Ok, first of all you have permission to laugh but here is my "rule of thumb" This is meant for a hobby situation not for industrial situations where trimming 10 seconds off an operation means the difference between profit and loss.
For speeds when cutting metal on a lathe or mill using high speed tools: 1000 rpm for 1/4 inch on ferrous metals of unknown composition. (This is the basis for all the further refinements) 3 to 4 times that for aluminum or 12L14 and 4 to 6 times that for brass, very slow for stainless. You can safely multiply these speeds by at least 2 to 4 when using carbide. Of course the actual RPM you use will be inversely proportional to the actual diameter of the material at hand; 2000 for 1/8 inch, 500 for 1/2 inch, 4000 for 1/16 250 for 1 inch etc. Feed rate and cutting depths are chosen based on what the machine will comfortably do at the appropriate cutting speed. I virtually never need to refer to any kind of calculator or chart but I always stay at a reasonable and conservative speed for the material and cutter at hand. If you want to check my rule of thumb against any published data I think you will find that it will come down on the conservative side in every instance. Keep in mind that if I use my method I will always start my machining with a safe and conservative speed but not so conservative as to waste a lot of my very valuable (well, sort of valuable) time. My goal is to not wreck an end mill while trying to save 2 minutes of cutting time. The problem with having a bunch of charts and graphs and calculations is that it is very tempting to not use them. In my case I remember one thing : *************************************************************************************** 1000 rpm for 1/4 inch diameter of tool for mill or drill or 1/4 inch diameter of material for lathe. now I can always go slower but only faster if what I am cutting is NOT ferrous. 2 to 4 timse as fast for aluminum and 4 to 6 times as fast for brass, very slow for stainless. Adjust the speed to account for how much bigger or smaller than 1/4 inch the actual tool or material is. ******************************************************************************** It is VERY VERY much simpler than it looks once you get your head around it. Cecil ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
