Denford Orac

[Twisted]

Should get my hands on an old Denford Orac CNC lathe but will need to convert from Tape Drive to PC control.

Has anyone done this before, if so I really need help on this as I have no idea where to start.

This post will be also on the Denford Forum soonish.

[cjmerlincnc]

Hi, Good easy decision. Rip the whole lot out and replace with Gecko drives and good breakout board. Also a VFD for the spindle with a Digispeed board to use with Mach3's PWM spindle control which is perfect for thread cutting.

Keep the steppers and spindle index and get a power supply for 75V DC.

Mine's setup this way and I'm cutting 316 stainless all day long. A good strong lathe although a little underpowered on the spindle. If I got the chance I'd try to fit a bigger motor and drive.

[Twisted]

Thanks, that's a start.
Any ideas as to how much this would cost?

[cjmerlincnc]

Hi, Well gecko's are about £60 each, Go to CNC4PC website for breakout board. VFD'S come up on ebay for about £25. Google for Digispeed for the price. I'm guessing by the time youv'e got it all sorted around £300-400. But then you will have an accurate machine that will last a long time.

[Twisted]

Thanks you've been a great help, looks like I may well do that.

Merry Christmas.

[Maurice]

Hi
I recently bought a same lathe ,as you did I was wondering how you made out. Did you had a chance to convert over and what software your using to drive it.
regards
Moe

[Twisted]

Not had a chance to convert it yet it's in the workshop with a cover over it, waiting for my bosses to release some funds to do the conversion.

[lordjw]

Any updates on this old project.

I have my orac stripped to bare bone and waiting for rebuild



Cheers!

Julius

[Twisted]

Hi Moe

Not been able to do anything to this lathe as bosses are not bothered whether it works or not.

[awemawson]

I converted one about five years ago. I kept the original steppers, stripped out the entire electronics and started afresh with Gecko 201's. There is just space to fit a Compac EN small footpring PC in the plinth. I made a new front panel with waterproof keyboard attached and had a monitor on a rear mounted arm.

I agree with the previous comment regarding underpowered spindle. Sold it about three years ago before I moved, and now have an Eagland CNC lathe sitting waiting to be fitted with a new controller. Rather bigger being based on the Colchester Chipmaster castings

[lordjw]

Hi

I got permission from the original poster to use this thread to post my Orac build.

Here is a picture of my Orac before it was stripped



I had the one with tool changer. If it had not had the changer I propably wouldn´t have bought it.



Unlike Andrew I did not want to keep the original electronics box since it weighed very much. I decided to cut the upper part of the box to be used as chiptray.



As everyone can notice, all the original electronics have been removed. If anyone needs original Orac electronics components please feel free to contact me. The Orac electronics were working perfectly. The CRT display has already found a new home.

Painted the chiptray black with Hammerite and will keep the stickers on chipguard to remind of the origins of this lathe.



Here are the Orac X and Z ballscrews. I have cleaned them thouroughly with lamp oil. Does anyone have recommendations about oiling of the ballscrews. Should they be oiled ? And with which kind of oil ?



Cheers!

Julius

[lordjw]

Orac assembly starts

Before reinstalling the carriage it is a good idea to check that lower surfaces of the bed are smooth. Usually the carriage moves in limited area near chuck and that area gets polished and other areas may accumulate dirt. I polished bed underside with oil and very fine steel wool.



This is how underside of the Orac Carriage looks like. It has been thoroughly cleaned and is ready to be installed.



Plates which lock the carriage to the bed from underside are very accurate. No shimming plates are used, fit is very accurate. If you detach the carriage as I did please handle the carriage carefully and maintain the original position of the plates.



At the picture below the carriage and the ballscrew.



Orac X-ballscrew has double ballnuts and backlash is removed by rotating one of the ballnuts against spring loading washers. Metal piece between the ballnuts connects the ballscrew to the carriage. I decided to oil the ballscrews with synthetic vaseline.



Thick mounting plate is placed between ballscrew assembly and carriage. Mounting plate adjusts the hight of the ballscrew to be correct for ballscrew end supports . Again no shimming plates, very nice build quality from Denford.





I let the ballscrew be slightly loose becouse I will have to mount end supports first before tightening the ballscrew assembly to the carriage.



To be continued...

Cheers!

Julius