H.E.S. 24NCS Lathe (24 X 60) conversion

Hello and thanks for the help ahead of time.

I purchased a machine shop from a retired machinist one year ago and am finally able to get serious about retrofitting the HES Lathe. It is an early 80's machine that had the original controller, drives, and motors stripped out when I received it. The original motors had been replaced with steppers and the new controller was made by Ahha, I am in the process of stripping the machine down now and rebuilding it with linuxcnc and Mesa cards. I have several questions to start with of what I am sure will be many.

First should I continue to use the stepper motors that are on this machine? I would like to price servos but don't even know where to start, where to buy, or what size. Any help here would be appreciated.

Second the machine has separate mpg's? for both the x and z axis that use motor generators and resolvers. The previous overhaul did not use these but they are still in place and might be good (might not also). If they are good is it possible and reasonably easy to use these with some combination of Mesa cards?

Third the previous owner had purchased a new ball screw to replace the old one on the x axis and I plan on putting this in but on the z axis there is about .005 of backlash, does anyone have thoughts on if I could get rid of most of this by replacing the balls in the nut? Or if this is a good idea?


Russell

Hello.
Were are you located? Maybe I can help you with hardware.
The use of steppers or servos depends, in my opinion on the size of the machine, although servos are "always" better.
Can you post a picture of the machine?

I am in a similar process of retrofiring using also mesa cards that I already have.

First should I continue to use the stepper motors that are on this machine?

Well you have them, they are installed and I take it they work properly.

Second the machine has separate mpg's? for both the x and z axis that use motor generators and resolvers. The previous overhaul did not use these but they are still in place and might be good (might not also)

If you go with your steppers you will not need them, so if they are bad it will not matter.

Are the stepper drivers in good working condition?

Third the previous owner had purchased a new ball screw to replace the old one on the x axis and I plan on putting this in but on the z axis there is about .005 of backlash

Is the backlash the same across the entire length of the travel? Are you sure the backlash is the ball screw and not the thrust bearing?

Rick G

emcPT

I don't have a picture that I can post right now but it is similar to the one at this website: fp1.centurytel.net/dansmachines/new_page_2.htm

Yea, I think I will go with the steppers for now and see how I like it. I am located in the Pacific Northwest, USA. Any help would be appreciated.

Rick G wrote:

First should I continue to use the stepper motors that are on this machine?

Well you have them, they are installed and I take it they work properly.

Second the machine has separate mpg's? for both the x and z axis that use motor generators and resolvers. The previous overhaul did not use these but they are still in place and might be good (might not also)

If you go with your steppers you will not need them, so if they are bad it will not matter.



Are the stepper drivers in good working condition?

Third the previous owner had purchased a new ball screw to replace the old one on the x axis and I plan on putting this in but on the z axis there is about .005 of backlash

Is the backlash the same across the entire length of the travel? Are you sure the backlash is the ball screw and not the thrust bearing?

.

Rick G

Yes, the steppers do work properly but I worry about speed and accuracy. I do think for now I will probably stick with them though.

The resolvers are not used to report the position of the different axis's to the controller but to run the machine manually. They are not mpg's but I don't know what you would call them (maybe a manual analog generator MAG?). They work similar to an mpg in that you turn the dial and the machine moves that axis a certain amount in that direction. They would be convenient to have working but it is not make or break.

Yes, the motor drivers are working and I have several of the same model as back ups, they are about 10 - 15 years old now.

How could I determine if the backlash is in the screw or the thrust bearings? Is there an easy way to check this without the machine running?

Russell

Thrust bearing endplay can be checked by putting a magnet base indicator on some fixed part of the machine and touching its indicator tip to the end of the ballscrew. Rotate the ballscrew by hand back and forth and the total indicator reading is how much the thrust bearing play contributes to backlash. With some bearing arrangements some of this can be adjusted out. You can assume the rest is ballscrew/nut or put your indicator base on the moving component (turret, saddle, cross slide, etc.) and put the indicator tip against the side of a turn of the ballscrew. Rotate the screw in both directions and TIR reading is ballscrew/nut endplay.