Centroid Community CNC Support Forum

The encoder on my mill is also belt driven with a very small timing belt.

Uwe

The encoder only had about 30cm/1ft of cable on it. I checked, if i can replace it completely, but there has been used a somewhat special connector, inside, so i had to splice the cable... How i hate splicing shielded cable But since i know that the encoder-cable is prone to receive a lot of electrical noise because of the length and running outside the cabinet and near the motor, i chose to go that way.

Unspectacular pic, but approximately 1h of fiddling



Not a real beauty, but 0,1Ohms at ~6m/20ft on the shield, seems to be fine.


I could finish the spindle-encoder completely today, spindle is running super smooth since my little overhauling, also the encoder runs without any wobble or vibration (the torque-arm is a piece of 0,2mm/0.007874" feeler gauge, btw).
So i am very happy

Ref-Z is mounted, too. First moves are made
Spindle turning, axes moving, reference-switches functional, could be fun at the weekend^^



I used 2K-EP-glue (3M DP490, to be exact) to fill the uneven underground for the reference-sensor. It can be applied to vertical surfaces without draining off or even moving at all... I clamped the sensor-holder to a spacer for curing, works like a charme.
Later, I made a very sharp corner at the "actuator" here, too, to improve accuracy of the sensor (just face-milled the small face of the rear-clamping-strip)
Maybe i won't need that, because i can also use the home-marks of the scales, but we will see

Besides that, i only updated my wiring-scheme (that eats hours, too...). But you better do that, while you still know what you have done there^^

First runs done

The scales are mounted and joined to the slides, and i also changed the Encoder to another one with 2000ppr. The first one was HTL and just sliiightly above the needed 5V...

Also the servos are tuned in a first apporach, i reached +/1count (23bit Enc) max. deviation, about 1,8µm.
But i will have to invest some more time there, the Z axis is cheeping very loud in standstill, no matter what parameters (even on default), and THAT BOTHERS EXTREMELY!! But i didn't manage to quieten that beast, yet (i will start a thread regarding this, soon)

I mounted my old top-slide (with magnetic-scale in it, hence the wound up cable on the right^^).
I still have to mill me a solid-toolpost for that lathe, now that the exact travels and dimensions are defined.
In the meanwhile, this slide will do it's thing, too, i already had modified it to more rigidity before.

Here a brief overview, and also some more detailed pics from the cabinet. Not that i would think my cabinet would be suitable for an example

Next, i have to finish the servo-tuning, drag-chains and centralized lubrication and scale PID tuning.

If there are any questions, please ask.













(if you can't see pictures, please tell me! Already happened once with ImgBB and me

You did a great job!
Wouldn't the X-axis scale have been better on the other side?
What motor are you using for the spindle?

For mounting the tool holder, I advise you to remove the small carriage, especially if you plan to do any cutting.

i do this on mine:

The X scale on my lathe is also on the same side for the reason it would be in the way if using the tailstock if it is mounted on the right side.

Uwe

indeed, I hadn't thought about the tailstock

On my Colchester Bantam, I fitted a magnetic strip on the underside of the cross slide and a miniature encoder head (and the limit switches) on the saddle. That way it doesn't impede either the tailstock or the chuck.

As long as you close off any holes on the top of the cross slide to prevent (magnetic!) swarf ingress, it's a neat solution.

You have to be willing to butcher your machine but I collect machine tools to use, not to run a museum collection.

Aurelien wrote: ↑Sun Jul 06, 2025 7:17 am You did a great job!
Wouldn't the X-axis scale have been better on the other side?
What motor are you using for the spindle?

For mounting the tool holder, I advise you to remove the small carriage, especially if you plan to do any cutting.

i do this on mine:

Thank you!

The scale is on the left for two reasons:
1. When the scale is near to the cutting-edge, the deviation by cutting-forces between cutting-edge and scale is as small as possible.
On the right side, the deviation from cutting-forces would be much bigger, as the slide will always turn around the Y-axis when pushed from the cutting-forces. You can't really get rid of that, because the slideways need some play for being able to move.
Therefor it's placed near the cutting-edge.
2. And, as Uwe already mentioned, the tailstock would have to bridge much more distance.

The motor is still the original one, a 850W asynchronous-motor. I will see if this is enough, i still can mount a servo later.

What you have there is what i meant with solid-toolpost
The stiffness of the tool/machine will become much, much better with such a solid-toolpost, as you said.