There is no reason you cannot used a toothed belt and pulley at the other end. As long as the lead screw backlash is taken out somehow. On my Gingery Lathe I have two ball thrust bearings on either side of the lead screw bushing taking out the backlash. At the tail stock end a toothed pulley goes to the stepper motor. I've not had any problems.
> -----Original Message----- > From: Linden [mailto:l...@island.net] > Sent: December 25, 2023 11:39 PM > To: Chris Albertson; Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Ball Screw Driving Questions > > Thanks Chris > > This is exactly the insight I was looking for now I understand why the > conventional mounting is always with the servo at the head stock end. > > Linden > > On 2023-12-25 22:35, Chris Albertson wrote: > > When it comes to flexing and bending, think about the bed too. If the > servo motor and pullies are mounted at the tailstock end, then the bed will > carry the reaction forces and see exactly the same tension and �twist� force > as the screw. But if the motor is mounted at the headstock end the bed sees > no net forces. > > > > The twist force on the bad will be the motor�s stall torque times the pulley > reduction. Would that be enough to warp a cast iron bad? That depends on > the detainees. > > > > Also you. want the force of the motor applied to the fixed end near the > headstock because none of the mounting points will move as force is > applied. > > > > In short, think about what bends as force is applied, the motor pushes on > the screw one way and the motor mounts in an equal but opposite direction. > > > > > >> On Dec 25, 2023, at 3:37�PM, Linden via Emc-users <emc- > us...@lists.sourceforge.net> wrote: > >> > >> Hello All, > >> > >> In the early stages of converting a 13 x 24 inch manual Chinese lathe > >> to > run with Linux CNC. > >> > >> I have 2 questions regarding replacing the Z axis lead screw with a 3205 > ball screw: > >> > >> What I am thinking is mounting the fixed end in a pillow block at the > >> head > stock end of the lathe and the floating end in a second pillow block at the > tail > stock end of the bed. The question I have is there any reason I shouldn't > drive the ball screw from the floating end? My logic for driving at the > floating > (tali stock) end is 1 I have more room for belt reduction at this end and 2 > with the fixed end of the ball screw at the head stock end is that the ball > screw will be in tension when it is pulling the carriage toward the head stock > during cutting and less likely to flex or bend. > >> > >> The second question I have is what would be a realistic cutting speed > range for the ball screw in RPM? The servo motor I am using has a top speed > of 3000rpm and I am trying to figure out reduction ratio that is realistic. > >> > >> Thanks in advance for any help or suggestions. > >> > >> > >> Linden > >> > >> _______________________________________________ > >> 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
