Denford Orac conversion to new CNC controller

[xander janssen]

Hi all,

Recently I bought an Orac with production number 64 (june 1984).

The previous onwner has completely stripped all CNC related parts (control cabinet is empty and steppers are removed, main motor still present).

All important surfaces (bed, bearings, ballscrews) were completely free of rust and heavily covered in oil and grease.

Over the last days, I completely disassembled the machine, except from the main spindle which I could not get disassembled without using excessive force. All parts are now cleaned and re-lubricated. Next step will be ordering all CNC controls to convert it to EdingCNC, which is a (semi)professional CNC hard- and software controll from a Dutch company.

Plan is to mount 2 Nm stepper on the x-axis and a 2.5 Nm to the y-axis and adding VFD to the main motor.

I would like to build an enclosure comparable to the one in the image-link below.

viewtopic.php?t=3782

The original belt covers I will preserve for authenticity as they contain the numbered tags, but discard the original stand and electronics bay as this is dented, rusty and it puts the lathe too high over my workbench anyway.

Now I have some questions:

- Was anybody succesful in replacing the main bearings? And if so how did you get the assembly apart? I did not succeed, not even with heavy pulley pullers
- Does anyone know the RAL color of this lathe? I would like to repaint the bed and give the new enclosure the same (similar) color.

Regards,

Xander
Belgium

[xander janssen]

Some progress after disassembly, cleaning and reassembly

X-axis running on the new 2Nm stepper with Leadshine EM556S 50V 5,6A driver
https://www.youtube.com/watch?v=zUJKHPmPPeI

Main motor running on new Lenze 8201 VFD
https://www.youtube.com/watch?v=rTGC9MusSp8

[kfm36]

Xander

I am refurbishing a similar vintage Orac and have obtained replacement spindle bearings. I found the set of instructions below for removing the spindle over on the mycncuk forum. I have sourced the M20 rod and nuts/washers, just need a suitable pipe to go over the spindle nose before I give it a go.

Kevin

The spindle comes off fairly easily... Just need the right tool!
1- on the back of the head you will see a small slotted sensor attached to a metal plate - remove that... It is attached to the head with 2 bolts If I remember right?
2- from the back of the spindle remove the locknut, pulley and perforated disk -> You will probably need a bearing puller to bet the pulley off
Important: check for grub screws on the pulley before pulling with the bearing puller!
3- Now comes the custom tool! You'll need a M20 threaded bar + washers and nuts + a piece of tube with an internal diameter greater than the spindle nose about 5" long + a big washer with an external diameter greater than the tube diameter (this could be just a piece of metal with a 20mm hole in the middle...).
pass the M20 threaded bar through the spindle, place 2 washers on the threaded bar against the back of the spindle and 2 nuts behind them locked against each other.
Now from the front of the spindle, place the piece of tube around the nose, then the big washer behind it, then 2 washers and a nut.
4- With 2x 30mm spanners or adjustables... screw slowly the nut in the back of the spindle against the one on the front (clockwise).
The spindle will slowly but surely move out...
5- Done!

[xander janssen]

Since my last message, a lot of things happened.

- The control cabinet for EdingCNC is finished including 2x stepper drive 50V 5.6A for the two 2.5 Nm steppers, a modern VFD and safety circuit
- An interface plate for the spindle nose of was fabricated such that it can hold my modern 4-jaw, 3-jaw, ER40 collet holder and faceplate.
- chip guard for the x axis was missing so a new cover had to be build

[xander janssen]

Gently cutting the collar to reduce its lenght by 15 mm such that it will accommodate the modern chucks

[xander janssen]

All tests were successful.

Now moved to the final location for further installment.

[xander janssen]

First cut

20211222_204044.jpg (22.26 KiB) Viewed 17255 times

[xander janssen]

First part, the head of a 1:25 scale model gas cylinder.

20211224_140919.jpg (254.47 KiB) Viewed 17237 times