It's an upside down "L" shape, how about a sacrificial block that turns the "L" into a block?
Martin Oops. Forgot the raw material photo. > -----Original Message----- > From: John Dammeyer [mailto:jo...@autoartisans.com] > Sent: August-03-21 2:28 PM > To: 'Enhanced Machine Controller (EMC)' > Subject: Re: [Emc-users] Something went wrong. > > That's a good suggestion John F. Thanks. I did do some more playing around > and it's clear the part flexing and the backlash both > were at fault especially with the plunge to the next depth. > > And that brings up another issue. One of my pet peeves with electronics > project magazines is they are great at a schematic and > either point to point wired or PC board but very little energy is spent on > describing various ways of mounting or installing in a > cabinet. Especially with the concept of Human Factor Engineering which is > the practice of making something easy to use or even > intuitive. Like an ESTOP button is always a red mushroom Not a toggle > switch. > > Same goes with work holding. Youtube has tons of videos that show a tiring > sequence of a milling cutter sprayed with coolant > making chips for 3 minutes with 3 commercials interjected, one every minute. > But very little on work holding. > > The next part I am making is shown in the attached screen shot rendering. My > raw material is in the second photo. So the question > is about work holding and how or what features of LinuxCNC can be used to > make this easier. > > I can use my band saw to create the initial width and split it into two L > shapes. But after that I start to have problems, due to lack of > experience I think, on how to firmly hold it and mill the stuff with a 5mm > and 6.35mm (1/4") cutter. > > Suggestions? > > Thanks > John > > > > -----Original Message----- > > From: John Figie [mailto:zephyr9...@gmail.com] > > Sent: August-03-21 11:59 AM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] Something went wrong. > > > > Speaking of backlash. My tiered old Bridgeport has about 0.002" of backlash > > in the ballscrews. So if circular interpolation is used there is a small > > bump at each 90 degrees of the circle. But if I make the finish pass first > > clockwise and then repeat counter clockwise the imperfections are much > > smaller. I know from experience with my first CNC machine that's built that > > actually used leadscrews with lots of backlash the clockwise followed by > > counter clockwise method was remarkable compared to a single direction > > final pass. > > > > John > > > > On Tue, Aug 3, 2021, 10:10 AM jrmitchellj <jrmitche...@gmail.com> wrote: > > > > > You might try the run again without the backlash compensation in LCNC to > > > get a feel of what it is actually doing. > > > > > > > > > --J. Ray Mitchell Jr. > > > > > > > > > ?I predict future happiness for Americans, if they can prevent the > > > government from wasting the labors of the people under the pretense of > > > taking care of them.? > > > > > > THOMAS JEFFERSON > > > > > > > > > On Tue, Aug 3, 2021 at 6:24 AM Gene Heskett <ghesk...@shentel.net> wrote: > > > > > > > On Tuesday 03 August 2021 05:31:56 andy pugh wrote: > > > > > > > > > On Tue, 3 Aug 2021 at 07:58, <marcus.bow...@visible.eclipse.co.uk> > > > > wrote: > > > > > > I draw all this from my own ballscrew conversion of my own mill, > > > > > > some 20 years ago. If I was doing it again, I would use two nuts, > > > > > > with spring tension between the pair > > > > > > > > > > Springs might not be the best way. The common way to tension double > > > > > nuts is to (basically) screw them into each other and lock the angular > > > > > relationship. > > > > > > > > > > You _can_ get preloaded single nuts, using oversized balls. That only > > > > > works if the ball track is the right shape, though, it needs to be a > > > > > 4-point contact shape. > > > > > > > > Which I'd suspect as being subject to rapid initial wear until it was > > > > just a normal screw with about a thou of backlash. > > > > > > > > For me, I bought C7 grade which may have 2 thou but in several years has > > > > not gotten significantly worse. Protecting the screw from contaminants > > > > is the most important thing for long life. On my Sheldon, the Z screw, a > > > > 1450mm long 25mm C7, got sealed bearings on both ends, a collar to clamp > > > > a bellows to on both ends of both sections, and 2 of the 6 mounting > > > > holes in the nut were drilled all the way thru so air could get from one > > > > side of the nut to the other as the nut moved. The nut gets one pump of > > > > grease a year. Backlash, some of which is in the end bearing, was about > > > > 1.9 thou 5 years ago and still is. It has not been uncovered in that > > > > time. I don't have a bellows on the x screw but its channel in the > > > > carriage is sealed top and bottom unless the carriage is clear in. > > > > exposing the screw behind the QCTP boss. No compound since LCNC is > > > > better than mechanical you set by eyeball. Plus it was busted from a > > > > fallover when I bought it. I keep a rag over the slot in that event. > > > > > > > > That faint thumping? Me, knocking on wood, no swarf has gotting into it > > > > yet... > > > > > > > > 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 > > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
