Table Top CNC Motor Spindle

[Sharpness10]

Hello, New to these forums as registered, but I cant find the information I am looking for for the life of me. So if you can, please help me out. I am currently planning to build a completely DIY CNC lathe with tool turrets, tool changers, cooling, the works. But since it is DIY, I am on a budget. I want this lathe to be able to accurately cut threads, so I need some sort of spindle motor that knows its position. Going from here I have a question. What motor would you suggest to use ( Knowing that the chuck is 100 mm in diameter and the motor should be around 1 kW, maybe a little less ) ? I know Servo motors can be used for this with great accuracy and success, but they are quite expensive. I have seen people use regular motors with induction sensors on the shaft to count steps, but I am not sure what kind of motor do they use and what kind of control, would be great if someone could explain in greater detail. I hope someone can help with picking the correct motor without overspending !

 

[Vancbiker]

Wrong forum. You should find a more hobby machine focused forum. Few folks here are messing with budget DIY stuff which is why did not find much when searching here.

 

[jmkasunich]

You are going to get a hard time from the crowd here. Your question would be more appropriate at CNC Zone.
That said, I'll give you a bit of an answer: you should separate the motor function from the spindle position measuring function. You aren't going to want a direct drive spindle. Lathes need a wide speed range for various workpiece diameters, and you'll want several different gear (or belt) ratios between the motor and the spindle. Choose you motor to give you the speed/power/torque you need, can be a regular induction motor most likely. No encoder needed. Then put the encoder for threading directly on the spindle.

 

[Sharpness10]

You are going to get a hard time from the crowd here. Your question would be more appropriate at CNC Zone.
That said, I'll give you a bit of an answer: you should separate the motor function from the spindle position measuring function. You aren't going to want a direct drive spindle. Lathes need a wide speed range for various workpiece diameters, and you'll want several different gear (or belt) ratios between the motor and the spindle. Choose you motor to give you the speed/power/torque you need, can be a regular induction motor most likely. No encoder needed. Then put the encoder for threading directly on the spindle.

Ah I see, sorry about the wrong forum thing. Was kind of getting desperate. Regarding idea with the induction motor idea, from what I understand, the cnc itself will not be able to accurately control the speed, so I assume the stepper motors that drive the axis will be able to compensate for that difference in speed ? I am asking this, since I am not sure how mach3 would handle this, if it knows the speed and the variance of it, but can not accurately control it. But your idea does give me hope, so thank you for that !