The lathe is perhaps the most important machine tool in a workshop. In almost every kind of machining operation, either the work piece or the cutting tool turns. – link.
We are approaching the lathe in a rather nonconventional way at Factor e Farm. We already have a heavy rotor with a detachable 20 hp hydraulic motor in the LifeTrac infrastructure:
What if we convert this rotor to a lathe? See more on the wiki. The program is to mount the rotor to a 640 lb steel table (welding table), and see how well we can do to start a multipurpose machining center. We proposed a similar concept before, but alignment issues remained unresolved in that program.
The present concept replaces the concrete block with a heavy metal table, uses the auger rotor above, and replaces the long rail with a 4-point alignment mechanism:
The basic concept is that you start with a perfect rotor and 1 7/8″ shaft as above. The bearings hold the shaft tight to what I would guess would be about 10 microns. Add a 12 inch chuck, off-the-shelf, with a professionally machined mounting plate, and you still have that level of accuracy, if your structure is stiff enough. That is the case if either you have a very beefy structure for 20 hp of lathing, or you can get away with a weaker structure if you run the motor above at low power such as 1 hp. That’s the beauty of hydraulics – you can control power and speed easily.
Add a rotary table with cross slide to the above scenario, plus a tool post and vise. Allow the cross slide to mount either horizontally or vertically, for lathing or milling on this lathe.
The rotor is perfect and easy to come by, but alignment is the showstopper for this project. When the rotor is attached to a structure, it is not aligned with much accuracy relative to the working table surface. The plan is to use a four-point alignment platform: four 1″, fine thread bolts under the workpiece assembly. This way, combined with the rotary table, we could have perfect alignment on the x-y plane of the working surface, plus perfect alignment along the axis of rotation. This is the present plan. If you have suggestions on a better cross slide than shown here, let us know. The cross slide is a weak point now, but it can be replaced readily.