On Tuesday 30 July 2019 22:52:06 Jon Elson wrote: > On 07/30/2019 09:14 PM, Gene Heskett wrote: > > Greetings all; > > > > Like Jon said on the sheldon list. woodruff keys cut into a case > > hardened shaft are a bear. Carbide makes a mark, for about 5 > > seconds. > > > > So it appears I will have to dig the keyways by EDM. > > > > Because the electrode will go away too, what makes the longest > > lasting electrode material? > > > > And which polarity, if it makes a difference? > > I think you want workpiece positive, and either graphite or > copper makes a good electrode. > Unless you do it with a second pass and new electrode, the > slot is likely to get a taper as the electrode wears down. > > Jon > I'll make a container for distilled water, it seems to work better than k2, and write some gcode to sweep the bottom of the slot, going down about .0001 per pass around the loop. I've thought of using a motor brush like for a Dremel tool, but they're so short to start. Longer electrodes can be pulled and the ends squared up when the taper gets obvious. Or a copper wire set to wobble, and bent to cover the needed width as its being rotated, could always be filed by dragging it on a file so as the keep the bottom of the slot square. The shaft came with an expanded web sheathing which is padding it in the vice right now, so its probably isolated from the vice. That will allow the file to be clamped to the vice. For the reservoir, I'll machine a medicine bottle lid to be water tight on the shaft, and mill an electrode slot in the side of the pill bottle. Fill it to the slot in distilled water & write the gcode to pick the wire out and take it to the file, incrementing the depth there by that same .0001" per pass. Air hose the file occasionally to keep it clean. I haven't measured a key for height though, but can measure the key in the old shaft to get an idea of the depth needed.
Nobody said it had to be fast, and it won't be but by keeping the wire sharp, and wobbling about the key width (.189") it ought to work. I damaged the inner edge of my taperlock hub with the trapped key trying to get it out, but I've now got that polished smooth a again, and have now machined a slot for key access, matching the slot remains in the pulley which should make re-inserting the key a heck of a lot easier. There's very very little room, and a relief cut in the small end of the taperlock will make it considerably easier to get everthing in time so the key just tips into place. The flange of the taperlock robs me of the space to do that, so the key has yo be put in while the taperlock hub is backed away and loose but the shaft when the key is inserted is about 3/4" left of where it runs. Once its in, the shaft is moved to the right, carrying the key in past the taper, then the drawbolts are tightened to about 1/16th turn from broke, going around the hub until they don't move any more. With the working room I have I'll have to make the wrench into a really short arm, and with the belts dragging, tightening will take at least an hour, it took 2 to get them all loose to take it apart. I've even considered leaving that key out and depending entirely on the taperlocks grip. There is no wear mark on the key now so it hasn't been slipping and slapping against the key even when the old belts are yelping at the rigid tapping turnaround while reversing an 8" 40+lb chuck. And my back is still complaining about that 2 days it took to get it apart. With the shaft re-installed, raise it as high as it will go, to get enough room to join the powerbelts I'm going to try to put in, then see if it has enough tension when its been lowered to the max again. run for an hour, jack it back up and see if enough slack to take another link out can be found. The guy in the Fenner video, he doesn't have hands, he's got to have fingers with built in vicegrips disguised to look like fingers. I might wind up putting fresh but normal belts in it, in which case it won't be together for another 2 weeks because I'll have to take it all back apart again. Supposedly matched of coarse, these sure as hell aren't. But I'd guess they are 40 yo too. 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis 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
