DIY CNC Metal Lathe Build (Part 1) - Spindle Restoration and CNC Conversion

[GBWM]

Hi!
This is the first part of my DIY CNC Metal lathe project. This is my second attempt and I hope it will turn out much better than the first one.
In the first part I show the process of a short restoration of an old milling machine spindle and drive system modification. I swapped the old bevel gear for a HTD belt type pulley. Later on I'm going to attach it to a 2.6kW or 3.8kW AC servo.
Let me know what you think!

[gcrimi2005]

There the efforts are not indifferent and
I'm just wondering how long the timing belt will last,

[GBWM]

We will see. The supplier states the belt is somehow strengthened with cords inside. According to the catalogue it should be enough for that torque.

[tonyfoale]

There the efforts are not indifferent and
I'm just wondering how long the timing belt will last,

Similar belts last a long time driving cams on IC engines which would be more arduous duty.

[gcrimi2005]

In the past, to increase the spindle speed of a lathe grinding machine, I had used a toothed belt, thirty seconds after the first start-up it exploded.


I have always seen the belts mounted on the outside of the motor body, for easy replacement and for the black dust they release. There in a closed environment, I think a chain is more suitable. More durable, it doesn't dirty the inside of the crankcase. Of course at the price of greater noise.

[tonyfoale]

In the past, to increase the spindle speed of a lathe grinding machine, I had used a toothed belt, thirty seconds after the first start-up it exploded.


I have always seen the belts mounted on the outside of the motor body, for easy replacement and for the black dust they release. There in a closed environment, I think a chain is more suitable. More durable, it doesn't dirty the inside of the crankcase. Of course at the price of greater noise.

Chains give a rougher drive which is not desirable for a precision machine tool. As for cleanliness, a chains throws off lubricant and needs frequent lubrication, their one advantage in this particular application is that they can be replaced without dismantling the spindle assembly. There are countless millions of notched belt installations throughout the world which do not mimic your failure in 30 seconds. If your experience was typical then such drives would not be still in existence.