Hardinge HC Lathe - CNC Conversion

I agree, if there were a belt or gear drive, there would be significant radial loads on the shaft, requiring a support bearing.

While there is no belt drive, it is a good practice to support long and relatively slender shaft in at least two places to prevent 'whipping' at certain speeds. I was understandably happy with the ball screw end of the shaft - which is rigidly clamped to the ball screw , and well supported by the angular contact bearing. I was uncertain if the flexible coupling at the motor end, by itself, would provide sufficient support. Also, flexible coupling are known to produce side loads on shafts, the size of which is dependant upon the type of coupling, and the axial misalignment of the two shafts. While these loads are significantly less that those from belt drives, they are a factor.

Anyway, while I may have got away without a bearing, there were a few known unknowns, and I thought it prudent to fit a bearing to the motor end of the shaft - just to be sure.

Cheers, Steve.

Skippy1 wrote: I was uncertain if the flexible coupling at the motor end, by itself, would provide sufficient support.

Good point, I had missed the presence of the flex coupling.

With that length of shaft you could probably have not used a flexible coupling at all from a radial perspective, but there would still need to be some allowance for axial shift if the motor bearings and ballscrew bearings are to avoid "fighting" each other.
I have nearly always used a belt (or inverted-tooth chain) on my drives so I am not really up to speed on direct drives.

Clean build! I also did a Hardinge retrofit, but I started with one that already had a Bandit CNC.

What GUI are you using?

It looks like you are using the manual lever for tool changes. Mine already had a rotary air cylinder that replaced the lever. I wrote a custom component to operate the tool changer if you are interested.

I'm currently using the standard Axis GUI.

Yes, manual tool change for now. Sometime in the future I would like to convert the tool turret to CNC control. I have already got a small Parker geared servo motor, which I think may be suitable for operating the indexer.

Cheers, Steve

Nice clean refit. I wonder how similar the turret is to my Hardinge CHNC... it looks similar.

JT

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.