CNC Lathe Conversion – 8
by John
Continuing the installation of the ball screws, and stepper motors.
I have completely removed the digital read out module and glass slides, and they will not be reinstalled. Not sure what I will do with them. They are only a year or two old, and in good condition. I will probably put them on Ebay. Same with the old gearbox, carriage apron, and electric controls.
Here are some pics of the plates and blocks which support the ball screws and steppers.
This is the steel plate at the headstock end, bolted to the bed. And the block with the holes is cast iron 42mm thick, to support the leadscrew and leadscrew stepper motor. It was machined out of an old piece of machinery, hence some unintended holes. Being cast iron it was fairly easy to machine, but incredibly dirty. Turned everything in the workshop black, including me. (whoops. Unintended not PC)
This is the block which replaces the gears and controls of the apron under the carriage. The thick block is cast iron, and the stepper motor support is 20mm thick steel. Very heavy.
This plate is hidden under the carriage. It secures the lead screw nut.
The slot in the carriage had to be widened and deepened a bit, in order to accomodate the slightly fatter and taller cross slide nut. See the next photo to see the setup for milling the hole through the carriage.
A rather confusing photo. The carriage is clamped to a large angle plate on the mill, and I am enlarging the hole which accommodates the cross slide ball screw. It was at the limit of what my mill could manage. An intermittent cut, with a lot of tool stick out. Not the best way of doing the job, but it worked OK.
Plastic covers attached to the stepper motors, and toothed belt pulleys fitted.
Checking the centres between the pulleys, using 2 wooden wedges to push the pulleys apart.
The underside of the carriage. The hole and channel at the left side of the picture was machined to accept the larger cross slide screw
So you can see that I have been busy since the last post.
At present the lead screw is at Linear Bearings in Melbourne, having the ends machined to accept the driving pulley, and support bearings. I did consider doing this machining myself, but decided to leave it to the professionals because of the high cost of the item and the hardness of the material.
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