On Friday 28 February 2014 12:48:57 Jon Elson did opine: > On 02/28/2014 12:31 AM, Gene Heskett wrote: > > This latter is a common lament from all of us table > > toppers I imagine. I am amazed that they put in something > > that can only turn 2500 revs, then we put motors on it > > that are fully capable of moving fast enough to stall said > > motor even when its in low gear, and that of coarse leaves > > you with a pair of carbide pieces worth 10 to 20 bucks, to > > be dropped in the recycled carbide container. That was why > > I was asking a few weeks back about those 12k rpm R8 > > spindles on fleabay. > > The Taig "CNC" mill has a 10K RPM belt drive scheme. > I think it would be fairly easy to get higher speeds on > many of the tabletop machines with minimal work. > > > You folks shot me down saying the run out was probably > > well over 3 or 4 thou. These little table toppers really > > ought to have spindles capable of marching that 1/8" 2 > > flute carbide bit, plowing a slot .06125" deep in an alu > > workpiece (with mist lube & prayers that its hard alu so > > it cuts clean & doesn't gum fill the bit=instant quiet > > little "tink" > > The trick to aluminum is to take shallow cuts at a high > feedrate, > and repeat with enough passes to get to the depth you need. > The high feedrate sees to it that the aluminum doesn't get hot > enough to soften. And, 90 F is enough to soften it!
Tell me about it! I bought a block of alu scrap, nominally 7"x7"x30something" long, and have been slicing off the pieces that I need for raw material. Even with a mister going, I can't work that stuff at all when its over 90 in the shop. I can make nice stuff at 50F just fine though. Its a right PIMA when its nice & comfy out. Even on the bandsaw table as I freehand the piece, if the sun is shining on the saw, I can gum up and seize the blade if I'm not careful or don't keep a crayon of door- eze handy to give the blade a coat of wax frequently. > I had an accident many years ago with a 1/8" piece of 2024 > aluminum and a 1/8" solid carbide tool that gave me some ideas > of what they can take. I forgot to set the Z first, and the > tool > plunged full-depth into the plate and started running across > it at 40 IPM. It was cutting JUST FINE, depth = tool diameter, > and full width in the aluminum! It was only when I hit E-stop > that the cutter broke! This was at 2720 RPM (fastest my > mill goes without overspeeding the motor.) Sounds like the spindle stopped quicker than the mill. I am familiar with that myself. :( > Jon > > ------------------------------------------------------------------------ > ------ Flow-based real-time traffic analytics software. Cisco certified > tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow > Analyzer Customize your own dashboards, set traffic alerts and generate > reports. Network behavioral analysis & security monitoring. All-in-one > tool. > http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.c > lktrk _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> NOTICE: Will pay 100 USD for an HP-4815A defective but complete probe assembly. ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. Cisco certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer Customize your own dashboards, set traffic alerts and generate reports. Network behavioral analysis & security monitoring. All-in-one tool. http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
