On Tue, Jun 23, 2020 at 6:27 PM Jon Elson <el...@pico-systems.com> wrote:
> > That looks a bit like my X-2 hack (although mine isn't a > real X-2, it is the same machine.) > See http://pico-systems.com/minimill.html for some photos. > > I found one big problem was the Y axis handle assembly did > not have a ball bearing, but just a bronze sleeve and the > handle jam nuts would slowly tighten up until the axis bound > up. The X has a pair of ball bearings with the handle nuts > preloading them. So, I cut the Y axis handle bracket to > work the same way. > You can just barely see it in one of the pictures. > I looked at the photos, can you tell me anything about how the machine performed. If you milled a circle how off-round has it? Yes, the Mini Mill does not have a bearing in the Y axis. I installed a pair of thrust bearing that are held in place by the drive pulley and the nut on the hand wheel. It is really odd that Sieg did not put a bearing on the Y axis when they used on X. I wanted to keep this build VERY simple so I made a plastic plate that screws to an existing hole on the mill and then there is a pocket where the two bearings are press-fit into the plastic. I did not want to cut any metal as that would go against my "simple as possible" goal. I wanted this to be do-able with only hand tools. The goals is to say "look what can be done with a 3D printer and a screw driver." I looked at your photos. VERY similar design except I bought much larger X and Y motors than you did so there was no need to gear them down. I have torque to spare. They run 1:1 for X and Y. You wrote that you found the smallest ball screw you could for the Z axis. I took the other approach and used the largest one I could physically fit in the space. Mine is a 16 mm diameter. The difference is that your design spins the screw, my design spins the nut. I had planned to use aluminum like you did, then thought.... A 4 Newton Meter motor can produce no more than 4 Newton meters of rection torque even if it stalls. Plastic can handle a load like that. All the cutting force is taken by cast iron dovetails -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users