Hello all,


I am planning to build a reasonably compact table top lathe.
This is designed for a Ø100mm chuck (that I already have).
Axial (Z) travel about 250mm.
Radial (X) travel at least 50mm (to match the chuck).


I designed this around 1204 ballscrews and HGW15 linear rails. I tried to keep the saddle height as low as possible (68mm, which feels still quite tall compared with traditional prismatic/dovetail lathes).
The spindle is high enough so the saddle can slide a bit under the chuck. This is done to have the cutting force mainly as compression in the middle saddle and avoid cantilevered loads that would create rotational forces.


I am planning this machine to be working first in manual operation and add CNC capability for threads, chamfers and anything that require precision or more than one axis .
Handwheels are accessible on the front. Steppers, limit switches, wires and associated clutter fits in the back.


I geared the ballscrew to make the X axis behave like a left-hand leadscrew. There is room for belt driven stepper on the back of the saddle, but this is not an immediate priority.
The Z axis is also geared with bevel gears to make the handwheel face the user. Still a bit of work to be done there as the handwheel direction is inverted (maybe add a new gear stage to reverse direction?).
A side effect of using gears is that it will reduce the impact of stepper cogging in manual operation. With direct drive ballscrews, I have 1.8° cogging, resulting in 0.02mm "indexing" of the sliding movement. Using a 1:2 reduction brings that down to 0.01mm (although that will add some backlash).


For the spindle, I already have a 25mm silver steel rod with a faceplate welded on one end, mounted on pillow bearings and driven by a treadmill motor. On the long term, this would be upgraded to a minilathe CJ18 spindle with proper bearings .


What do you guys think of this?