On Sunday 07 August 2016 13:09:49 Gene Heskett wrote: > Greetings all; > > I seem to have a saddle that is bell mouthed. Or something. > > I can get a new saddle from LMS, about $60. > > I put the front tapered gib on last evening, parking a mag base .0001 > dial on top of the saddle with the finger riding the flat behind the > v-way. I had done this the day before to see how much of the brass I > could cut off the small end, and had then cut it off at that mark, and > about an inch longer on the fat end, then made the screw like R. > Kruger did. > > Drilling and tapping the screw hole was a trick as the clamp is hot > roll, and diamond hard in the center. The correct sized tap drill, > about 3.44mm's in diameter, went in at paint drying speeds for about > .200" and the first inch and a quarter just exploded. Took the remains > to my oldest drill doctor & resharpened it. Went back to the docs and > set up a G83 to finish it, at about .004 per peck, drowning in cutting > oil. Then did the same with the rigid tap g33.1, setting it for a > very small advance per peck. Took a while but didn't break the only > 4mm tap I had that could go deeper than the thread length as it had a > short section of reduced diameter. Entry worn a bit sloppy but works. > then milled the screw heads slots nominally .099" wide, 4 of them at > .2" > intervals .0625" deep, so as to be able to move to the next slot for > the screw head as it wore. > > So I go out to put that on it and useing the dial to see if I could > get rid of the carriages twisting on the bed, which makes it climb the > v-way and cut a bigger hole moving to the right than when going into > the hole toward the left. By several thousandths, > > But the dial refused to indicate less than a 2 thou diff on a repeat > move. So I kept driving the wedge farther. I wound up, without > creating a drag the z motor felt, driving the taper around 3/4 inch > out of the left end of the clamp. When I quit for the night, it was > all the way in and still showing a noisy 2.5 thou of jump. > > I'll take it apart again today, looking for why, and take .010" off > the mating face of the clamp while I have it out. I have not removed > the rack strip as its the back guide for tapered gib. And its thick > enough the gib rides the smooth side above the teeth of the rack. I > get the impression I am cutting thru a coating on the bottom of the > bed lip, or something in that category. The old gib plates were worn > about a thou bell mouthed on both ends, so I would have to assume they > were keeping that underlip fairly clean. > > In other words, I think the one of you who called it "the little > monster" hit it square on the head, and the name has stuck, because > its darned sure being one. :) To give some credence to the rubber > frame claim I've made many times, the replacement saddle's shipping > weight is 3 lbs. And I have seen it bow up or down in the middle from > cutting forces! > > When I am ready to run the Sheldon with a computer, I know exactly > where it will come from. That one's drive has room for dozens more > configs, and the the electronics box can serve as the starter kit to > drive the X. And I have the complete kit I took off the mill to run Z > with. Slow, but it will get the job done since the spindle is also > slower, and will go plenty slow enough without the noisy back gears > once I swap the 3/4 hp single phase 120 volt motor for a 1 hp 3 phase > motor on the inverter. With the inverter I have about a 6 to 1 speed > range. On that table, the motor seems happy with a 20 hz drive, or > with a 120 hz drive, and with its new bearings, maybe 180 hz. Limit, > now that I've had one of them apart will likely be fan disintegration > although it seemed failry substantial when my bearing puller leaning > into it to get a purchase on the old bearings. With a 4 slot pulley > setup down below, I ought to be able to spin at any practical speed > w/o the backgears. > > After getting a Z screw, the next biggest cost is tool holders for > that Phase II QC tool post, they are 4x the cost of the ones for the > little monsters smaller QC post. Ouch! And it only has 3 IIRC, not > near enough to be able to setup a usable tooltable. > > And thats the Sunday afternoon news from a small village in WV. :) I > hope everyone is well. > > Cheers, Gene Heskett
I can't read the date-time, that was all yesterday, and I did get it tightened up, after I threw away a mill bastard file I had been using to get a fit because it was twisted a good 1/16" in its length. Swapping to a flat file, even it it was duller, and I made good progress and had it down to .0005" of wiggle before I quit last night. So today, back to working on my code for tapered thread cutting, and I now have that nut made. The little monster is now boring some pretty threads indeed. The clamp looks like it will hold very well, considering it will not have any great thrust pulling on it, just the twist from the front handle when motor power is off. Motor power will come in from the other end when thats done. So that was a quitting point of sorts on that. But curiosity had me measuring the various pieces of the compound with its missfit tapered gib. I'll do like Andy did with his Holbrook, except I'll just machine another pad to sit on the crossfeed and fill up the space under the Phase-II. Everything on the compound is a mess starting with its base piece on the crossfeed. Only 2 bolts, and its been hammered around so it can rock on the crossfeed under the bolts, and the base V-Way itself is tapered about 20 thou, so there's no way to get a decent gib fit even if I did make another gib. So thats settled, its not worth screwing with. Fun and games as I'll need to put in longer hold down bolts so theres enough meat to bolt it down solid, but thats no biggie. That flange the holddown nuts were sitting on is maybe .1" thick max, flexible (permanently) under load. I think 1/2" is more like it. Same comment for the T-slot in the top the phase-ii is using, it could be deeper. There seems to be room in the OEM part to add another 1/4" of depth and move the holdown flange up quite a bit too. But I wonder if the G0704 has the cajones in low gear to turn that big a keyslot cutter, which I've not bought yet. That, and a 3/8" mill to clear out the center before the keyslot cutter goes to work that I'll be looking for tommorrow. Its going to be a while before I can make first swarf with this Sheldon I guess. 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> ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. http://sdm.link/zohodev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
