Centroid Community CNC Support Forum

I got this Hardinge lathe a few years ago and am just now getting around to fixing it. The servo for the X-axis is hosed.

Original Part# 3879
17-in/lb @ 5 amps
2350 RPM @ 120vdc

any out there?

I'd settle for some help with finding an inexpensive alternate.

Skunk wrote: ↑Tue Dec 03, 2024 7:07 pm I'd settle for some help with finding an inexpensive alternate.

I have this DC servo motor listed on eBay. Pulled from a working CNC router with very low hours. Made in Italy.

https://www.ebay.com/itm/144605007898

The motor is 83.5mm in diameter and 267.5mm long. If you need the spec sheets with full dimensions and motor specs PM me your email and I'll send you the PDF document for the motor.

Unfortunately, that length may be a deal-breaker for the Hardinge, because the X motor sits between the motor mount (which moves with the cross-slide) and the back of the bed. Increasing the length of the motor limits X+ travel.

The old Centroid 17 in-lb motor is probably around 7.2" from flange face to back cap (comparable to the original Hardinge motors).

cncsnw wrote: ↑Tue Dec 03, 2024 10:44 pm Unfortunately, that length may be a deal-breaker for the Hardinge, because the X motor sits between the motor mount (which moves with the cross-slide) and the back of the bed. Increasing the length of the motor limits X+ travel.

The old Centroid 17 in-lb motor is probably around 7.2" from flange face to back cap (comparable to the original Hardinge motors).

Would the current 16 in-lb motor be a better replacement? It is about an inch longer than the 17 in-lb.

centroid467 wrote:Would the current 16 in-lb motor be a better replacement? It is about an inch longer than the 17 in-lb.

It is usable but problematic. It would prevent the cross-slide from reaching its normal X+ limit, and the limit/home switch trip points on a CHNC are not easily adjusted.

If there is still a good short-case motor on the Z axis, then a new (longer) motor can be installed on the Z, and the short motor moved to the X.

cncsnw wrote: ↑Tue Dec 03, 2024 10:44 pm Unfortunately, that length may be a deal-breaker for the Hardinge, because the X motor sits between the motor mount (which moves with the cross-slide) and the back of the bed. Increasing the length of the motor limits X+ travel.

The old Centroid 17 in-lb motor is probably around 7.2" from flange face to back cap (comparable to the original Hardinge motors).

cncsnw - I found a print that you posted for the original motor. I do not have mine on hand to measure but am fairly certain they match your drawing. Z axis motor is intact, but not yet tested. I will assume it n is good for now. However, it is the longer version. On good side...I have removed all the covers and think that I can get away with using g them so a lo ger motor may not be an issue for now. Is there an reason that 2 motors of differing input voltages would not work?

This machine was already fitted with the Allin1dc when I acquired it. Pretty sure I paid less than scrap price for the lathe. Looking forward to getting this thing running. I'll start a thread once I get started.

I have the same motors and had them rebuilt; it was about half the cost of a new motor and done by an outfit recommended by Mr. cncsnw. The place is Advance Electric motors in Portland OR but maybe there are others doing similar work. The X axis motor had to be rewound and it took about six weeks.

Ive got a Hardinge CHNC with failed electrics. Not sure what it has yet, might have a replacement for you, will check this week. Why not just replace with modern AC servos?