I bought a 4th rotary axis, which I am not sure if I should be happy about on a "you get what you pay for" basis or should have received something better. Are my expectations too high from these 300$ things? This is what I bought (Option 2):

https://www.aliexpress.com/item/1005...47104c4dI8LQr7

Everything looks nice, but...



So the question is, if you think this is "normal" or not. I did complain to the seller, he asked to make a video to show the problems, so I made one today. I am still waiting for his reaction, but basically what I asked for is:

1. A new large gear or a chuck or both, because I thing that's the biggest issue.
2. A new MT2 live center., or at least a new pin for my MT2 taper.

Unfortunately, I don't know how to replace the pin or the large gear, so I also asked for instructions in that case. I don't know if the center pin is glues or not, but it sits so tight in the bearing that I can't remove it. I removed the three screws at the back of the large gear, but then there is nothing else to remove, and the gear still is firmly attached to the axis, so even there I need instructions because I don't know what to do. The chuck is more straight forward, I din'd try to remove it, but probably held only by three screws.

What do you think? I have zero experience with rotational axis, but dry running seems fun and works well with UCCNC.

I am also making a new 48V 7A supply just for this purpose, and also made a "Lathe mode" box, which basically is giving pulses and direction signal so that I will be able to run as a "lathe". I know, I know, don't laugh... it's not a lathe, but I will play with it and it may work for soft material. Anyway, if not good enough but I like the idea then I'll change the 1.8Nm motor to something considerably stronger, or a servo. Anyway, this device is based on an Arduino Uno and it will give pulses matching a set rpm, which can be set (as it is designed) between 0-350 chuck rpm. Of course, it has a display and it will accelerate/decelerate as well.

As usual, if there is an interest for this box then I will share the Arduino code, but will first make a box and everything before I will show it. It's a simple thing, but will be fun to try.