thanks for all the replies guys just answering everyone now
Gene i am using brushless AC servos already (just like your closed loop steppers only better) your steppers sound pretty cool but you will find that once you get into the larger kw sizes its best to just go straight to servo motors my motors are 3.5kw (steppers with the closed loop drives and encoders kinda become servo motors anyway at that point) regarding the ballscrew preload. i think i will try the scales first and then if i have issues i will look at ballscrews. currently i don't want to put a whole lot of time into this. just want to wire it up and forget about it and then make parts on it. i need pretty good accuracy on the z axis for height but currently the x and y axis don't actually matter too much for the job i have for the this machine right now and i already have a spare magnetic scale for the z axis so i will try set that up in a few weeks and test this dual feedback PID stuff I have a horizontal mazak 5 axis cnc 22ton beast, that has taken a year and a half now to get going lol and i know how these projects can stall a bit. i had a few issues with old tired drives and should have just pulled the pin and bought new drives early on but tried to repair them for awhile. because we don't have many people in new zealand that can repair them and i don't have the skills myself that didn't go well once i bought new drives it was easy lol but between the toolchanger and the pallet changer and something like 20 separate motors on the machine that all need wiring up to contactors or drives etc there is a lot of work now finally its all finished apart from the spindle motor. just got this last one issue. it's a special permanent magnet synchronous motor and i am having issues getting a vfd to run it On Mon, Jan 5, 2026 at 5:08 AM Sam Sokolik <[email protected]> wrote: > I would have to look again.. but I think I remember the k&t ball screws > are preloaded to 1 ton of force.. > > Sam > > On Sun, Jan 4, 2026, 10:03 AM Ray Henry <[email protected]> wrote: > > > > > Many of these commercial machines have double ball nuts and a linkage > > between so that they can be rotated against each other to take up wear. > > > > > On Sun, 4 Jan 2026 at 12:59, Stuart Stevenson <[email protected]> > wrote: > > >> > > >> I don't know how much preload is considered 'tiny'. The 5 axis Cinci X > > >> travel is 120". The preload stretch is supposed to be .007" measured > > >> with > > >> an indicator on a mag base on the casting beside the screw while > > >> tightening > > >> the nuts. > > > > > > That sounds very tiny on that length. It pretty much falls off the > > > bottom of this bolt-stretch calculator. > > > > https://www.engineersedge.com/hardware/bolt_elongation_formula_15777.htm > > > > > > -- > > > atp > > > "A motorcycle is a bicycle with a pandemonium attachment and is > > > designed for the especial use of mechanical geniuses, daredevils and > > > lunatics." > > > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > [email protected] > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
