Hardinge HC Lathe - CNC Conversion

Well, it has eight sides and T slots for tool holders, but that's about it. Unfortunately, the turret on a HC is strictly manual operation only - no CNC indexing like your CHNC.

Guys,

After some more delays, I managed to finish a Mesa 7i73 based control panel for the lathe today. The top three knobs allow manual selection of axis and increments, and jogging movements via the manual pulse generator. Two of the bottom knobs are Grayhill optical encoder/switches, which allow changes to spindle speed and feed rates while a program is running, to fine tune machining operations. Two knobs are also push switches, which allow start, pause, step, and resume of programs using, someone else's code

As always, thanks to the guys on the forum for advice on getting it working.

Nice workmanship. Would be cool if you could post a Youtube video of it in action.

Nice work and cool looking controller. How is it mounted? Is it on an arm? I did mine on my AHC so it can swing out of the way mounted on the right side. I still feel like having to wear a rain coat every time I use coolant as it gets all over the place. Will you be adding some kind of chip shield?

Thanks guys,

The panel has a bracket on the back, with a 3/4" pin which drops into a hole in the headstock, where the original Hardinge motor speed controller fitted. It can swivel, but not move.

I was considering mounting a removable sheet of 3/8" polycarbonate against the headstock, with a 6" hole to fit over the spindle bearing retaining/labyrinth seal ring. The perspective of the photo is a bit out, but the right hand side of the panel would be behind and protected by the poly sheet.

I'm a bit of a technophobe, and YouTube is a bridge too far for me. If I get my finger out one day, I may get something up, but don't hold your breath.

Cheers, Steve

Nice work!
Neat and tidy too.
cheers:)

Im a bit late to this thread but youve done something I am just considering.
Any chance you could answer more questions at length?
Was this a Hardinge "2nd operation" Lathe to start?
Is there an optical encoder or resolver on the spindle for position control?
You mention vfd in an earlier post but I dont see how you can thread repeatable without syncronizing the spindle and feed. no doubt youve done that.
Amazing work and workmanship.
Hope to hear back. Matt

Hi Matt

This started off as a Hardinge 'HC' lathe - a weird little production lathe fitted with an eight position tool turret, and no tailstock.

Typically, CNC conversions of these sort of lathes have used the tried and trusted solution whereby a separate toothed drive off the back of the spindle drives the encoder behind the head stock, (a bit like the Accuslide and Omniturn CNC conversions).

I've went down a different path, using the encoder fitted to the rear of the new spindle motor, and driving the spindle with a toothed timing belt at a 1:1 ratio. The encoder on the motor sort of keeps track of the spindle position, allowing synchronisation during threading operations. This is a less than ideal solution, as while the timing belt will prevent large errors, load on the spindle could possibly stretch the load side of the belt and introduce slight errors, and minor variations along the length of the spindle drive belt would cause a periodic error.

Anyway, I've had no problems with this setup using single-point threading, but I wouldn't want to try rigid tapping with it. I certainly wouldn't recommend this as a solution for anyone else! The only reason I did it this was that being a lazy sod at the best of times, when I got the new spindle motor and found it already had an encoder fitted, I believed that it would save me mucking around with a separate encoder, drive, and bracket on the headstock.

Cheers, Steve