On Tuesday 08 September 2015 04:24:01 Erik Christiansen wrote: > > I once bought a nearly 40 lb block of aluminum, about 6.5x6.5" cross > > section about 20" long that way. Been nibbling on that for smaller > > bit & pieces for a while, but it would take quite a large bag to > > hold the swarf if I sacrificed whats left of that, and its dead soft > > gummy stuff, wanting to pack up the flutes of your tools way to > > easily. And I'm not yet rigged for coolant on this mill. The table > > has a drain, but its way to small at 1/4" bore and would be plugged > > with swarf in less than 2 minutes. But I can see a small pool pump > > and a 5 gallon bucket of water if I could figure out how to rust > > proof it. I assume there is such a product. > > As has been mentioned here before, Gene, keeping chewing-gum grade Al > cool is the trick, and metho does that very well, without mess.
Metho? Thats a slang I've not encountered. > For > small jobs, I've repurposed a small long-nosed plastic oil bottle, > which can be persuaded to squirt, so its nose isn't so often nibbled > by the cutter. It's a pity that they sell pure gummy Al, when just a > few % Cu makes it nicely machinable, and stronger. (OK, enough Cu and > it'll age-harden, which isn't a good idea for rolling or extrusion.) Some of the 1/2" plate I made that jackshaft frame out of must have quite a bit in it, it machines great, but sounds as if I am grinding glass. The two end bulkheads carrying the shaft bearings are made from it, and its origin says it was rolled out in the later 60's as its part of the bracing skirt around the edges of a much larger sheet of it that was one part of an Ampex VR1200 2" quad vcr. Riddled with tapped holes to mount stuff, and the 6" holes for the NAB hub clearance, out in the weather for many years now, it carries a pretty deep greyish age patina. I was reminded of that Sunday while taking about 3mm's off the top of it to make sure it could rise enough in that pocket in the back of the lathes bed to compensate for the exchange of a 10 cog kit pulley for a 16 cog pulley in order to get some spindle speed back. That part is being a cast iron bitch. I had installed a small boss of this 1/2" adjacent to this pulley, intended to carry a 4mm screw that could be tweaked in and out so as to touch the bed casting, and thereby prevent this frame end from rising under cutting load tension far enough to allow the belt to slip by jumping cogs. But the required rise to compensate for a belt about 3 or 4 cogs too short exceeds that which allows a decent tension. That too high a tension made the end bearing walk down the staft and out of its pocket in the frame! So now, taking advantage of the fact that when I built it, I had ordered a spare pair of bearings, I lost my cool and there is now a solidly retained bearing installed in both faces of both end brackets. And waiting on me to find some of that fawncy loctite. So today that added boss gets relocated to a new set of holes about 6mm down from the existing ones as that bolt is restricting the rise needed and its now screwed completely in. Plus I need to find a hex head 4mm bolt so the thing is adjustable by wrench without taking it all back out of the lathe to access it with a 3mm allen wrench. Which it seems I miss-laid (or murphy stole it) late yesterday. IOW, I haven't got the darned thing together yet. > Yesterday, though, I just cranked up the spindle RPM so the chips were > flung off, and forgot about coolant on two pieces of extrusion, it > went so well. My facing went well, 1/4" bit, 3mm stepover, 1100 revs and about 450 mm/minute feed. And a bit of wd-40 when the bit looked as if it was starting to pack. And the jig to hold the motor worked well enough once I found a decently sharp pilot bit. That big chuck is a bitch, as it will not hold a drill under 3mm shank, so a 1/16" bit wasn't usable. So I need to obtain another R8/smaller jacobs shank (or a 3/8" threaded one) & mount a smaller drill chuck. Thats stuff for my bucket list... > Piping kero about the workshop sounds distinctly scary to me. Me too. I don't smoke anymore, quite about 27 years ago, and in the usage for EDM, I haven't ever had a fire even when using a big enough power supply that it could be heard a coule blocks away when running. So while is can be ignited, the fireworks so far have been deep enough no air could get there to make it burn. > > So treated for rust prevention water would be better. > > "Suds" (water & soluble oil) may in time make the mill table look > duller/greyish, but is fine so long as it doesn't sit in the sump for > so long that it begins to stink. A distinct possibility. :( > What about drilling out the table drain to a more workable size, and > hammering in a bit of brass pipe to fit a bigger drain hose > underneath? I have some 3/8" clear plastic hose that will fit it. But I've not yet rigged up the pump and tankage. The reason I even mentioned the K2 was that it would do a far better job of isolating the alu from the airborn o2 which is the cause of a large part of the heating when machining alu. The heat from the cutting is largely carried away by the chip, but the heat created by the instant burning of the alu as the tools cutting flute passes and a new film of oxide forms behind the edge is the major part of the alu getting hot when machined. With a mist of safflower oil coating it instantly, that heat almost vanishes. But that also fills the building with a visible fog, and screws up your attempts to keep your glasses clean for days. So while it works very well indeed, it has a nuisance price you have to pay unless you can figure a way to suck up the overspray & vent it outside. Probably not good on lungs either... Water soluble oil? Heavy on emulsifiers I expect. What do I ask for? > Erik > > ---------------------------------------------------------------------- >-------- _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "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> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
