4th Axis

grabcad

This fusion 360 model a 4th axis I designed and made for my milling machine which is a Warco WM16B, similar to PM25V, G0704 etc.The idea behind this design was to be able to use the work-holding as my lathe, which takes 100mm chucks with 72mm recess. The spindle has 20mm through hole for feeding bar stock. The base has a 12mm key to align it to the machine table and it has holes for M10 screws that align with the table's t-slots.The spindle was turned from a piece of steel tube pressed into a steel disk. It is driven using a T5 280x16mm PU steel re-enforced automotive timing belt. There is no belt tensioning mechanism, I found the optimum distance between the shafts by experimentation and made the parts accordingly. The spindle has 48 tooth aluminium pulley and the motor shaft I turned from 10 tooth T5 bar stock. The spindle runs on LM48548 taper roller bearings and the motor shaft is supported at the front by a 0608 bearing. The other end of the spindle is threaded M35 x 1.5 in order to use a lock nut to pre-load the bearings.The main supports are 25mm thick aluminium plate, the base is 16mm thick and the lid and sides are 6mm thick.I used the same NEMA 23 3Nm closed loop hybrid stepper / servo as for the other three axis of the machine. Torque and holding power are much better than I expected. It is able to tighten a ER32 collet nut using the 4th axis motion. I need to use around 20cm of leverage to trip the motor controllers out of position alarm.I intend to design tail stock and trunnion for this and will update the model in the future when those have been successfully completed. If you plan to build one or if you have any questions please comment below.