On Tuesday 25 September 2018 13:51:20 Les Newell wrote: > Hi Gene, > > If I remember correctly the piece I used was only about 18" long but > about 4" diameter. Delrin that size is pretty spendy. I just used what > I had.
Thats why I started with the 22" piece of A2 .500". But it did not turn out to be straight by about 20 thou, well beyond the range of my .0001" dial. > I was setting head alignment so I didn't need it to be that much > longer. If I can get the taper down to a gnat's over that distance I'm > happy. > > The laser setup has a lot of potential. I think this is how I would go > about it: > First align the laser as close to center as possible at the furthest > travel. Make two alignment marks on the spindle 180 degrees apart. > Align the spindle on one of the marks. > Zero all offsets so you are in machine coordinates. > Start at Z home and center the camera on the dot by moving X. Make a > note of the X and Z positions. Rotate 180 degrees, center the dot and > make a note of the X. > Add the two X coordinates together and divide by 2. Move X to this > value and zero the axis. You should now be dead center. > > Rotate another 180 degrees, Move Z by whatever step size Step size when using a lincurve is arbitrary, and from my measurements, most of the jumping around is in the first 7" away from the spindle. But I mentioned measuring to the tailstock barrel while pushing the loose tailstock down the bed with the carriage, so I did, putting a lincurve "corner" into every peak motion that found. Put that into the setp tables for the lincurve, and re-enabled it. From about .2" right of the MIN_LIMIT, it was just under +- .001" full length of the bed until I ran out of lincurve. That looked pretty good, so I rezeroed the z by moveing the tool out of the QC holder about a quarter inch. Ran the mt-5 carver over that painted for size 5c adapter I've been screwing with for a week. Got a fit pretty well dead on the money, so I put it all together with the ER-40 adapter, and measured its runout right behind the nut at .0003", which is about 7 thou better than it was, and definitely close enough for the girls I go with. Looking at the apron to see if I could move the nut to the right, I can by around 2" which would be a huge help. But I'll have to figure out where to put the pushbutton that is used to adjust the distance per click of the dial since the nut would then occupy the space the switch is in. I need to replace that switch anyway as its not making a reliable contact with my usual thumb pressure. So I've a big grin and a big pork chop in the skillet for dinner, and the weather is getting wet and noisy. Tomorrow is another day. And I'll figure out how to move the nut then. Progress has been made. Thanks Les. > you want in > your table and take two X measurements as above. Repeat until you run > out of travel. > For each Z position add the X values and divide by 2. You should now > have the values that need to go in your lincurve offsets. Depending on > how lincurve is set up you may have to invert the values. > > It is important to always try to keep the dot centered on the camera. > That way you minimize the effect of any distortion in the camera. > > Les > > On 25/09/2018 17:07, Gene Heskett wrote: > > That too sounds like a great idea, Les. Suggested OD of the Delrin > > to get that stiffness? At about 30" between centers... > > _______________________________________________ > Emc-users mailing list > [email protected] > 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
