DRO errors, or are they??

[John BaronParticipant @johnbaron31275]

Hi Guys,

Any digital device can miss a step, usually reading speed related.

[Dave HalfordParticipant @davehalford22513]

Have you swapped the cables around to see if the fault moves to the other axis display?

Have you tried zeroing the readings and using it as a basic measuring tool cutting out the maths?

There have been issues with scales changing reading when the motor is switched on, that was a lack of AC earth.

Edited By Dave Halford on 25/10/2020 16:43:10

Edited By Dave Halford on 25/10/2020 16:49:58

[Sam Longley 1Participant @samlongley1]

Posted by Dave Halford on 25/10/2020 16:26:23:

Have you swapped the cables around to see if the fault moves to the other axis display?

Have you tried zeroing the readings and using it as a basic measuring tool cutting out the maths?

There have been issues with scales changing reading when the motor is switched on, that was a lack of AC earth.

I had not thought of swapping the cables but will give anything a go.

I do have a wiring issue. Ever since I had the machine from new I have had to press the start/stop switch sometimes up to 5 times to get it to start. I have found that wedging a piece of wood against one of the components to push it up against the copper strips does help, as the clips that hold it in place are naff. Perhaps there is an issue there, but I tend not to stop the motor if poss, because I have found that having pressed the start switch & it does not start, if I then forget to press the stop switch it sometimes starts on its own whilst i am handling it. No fun with the chuck key in place. It has rapped my knuckles twice, but i gave it a good swearing at

However the DRO is wired through a different 13 amp socket & it is earthed to the lathe.

[Dave HalfordParticipant @davehalford22513]

The DRO doesn't like being the only lathe earth . There's a certain amount of earth leakage on power units that's noisy.

Edited By Dave Halford on 25/10/2020 18:11:21

Edited By Dave Halford on 25/10/2020 18:11:54

[Sam Longley 1Participant @samlongley1]

Posted by Dave Halford on 25/10/2020 18:06:17:

The DRO doesn't like being the only lathe earth .

I am confident that the electrician who wired my workshop did it properly. Whilst the lathe itself is poor the earthing in the workshop is Ok. The mill DRO works perfectly well. I could disconnect the earth from the lathe, but i cannot see how this alters the readings. I will try it though.I will give any suggestion a go, thanks

[not done it yetParticipant @notdoneityet]

Dave H has indicated so many possibilities that have not been considered. If the resolution of the readout is only 0.01mm, do look up the specified system accuracy – it is likely rather more than you think. That alone could account for some of the apparent discrepancy suspected.

At present, posters are simply going round in circles.

[Dave HalfordParticipant @davehalford22513]

Posted by Sam Longley 1 on 25/10/2020 18:10:20:

Posted by Dave Halford on 25/10/2020 18:06:17:

The DRO doesn't like being the only lathe earth .

I am confident that the electrician who wired my workshop did it properly. Whilst the lathe itself is poor the earthing in the workshop is Ok. The mill DRO works perfectly well. I could disconnect the earth from the lathe, but i cannot see how this alters the readings. I will try it though.I will give any suggestion a go, thanks

I'm sure he did to, but the issue can be in the lathe check the mains cord earth is terminated on the earth spade properly, no paint in the way of a good contact on the mounting stud etc.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Sam, if your lathe and DRO are earthed via their supply leads and then you connect an earth between the DRO and the lathe, you could have an earth loop. Earth loops on audio equipment connections produce an annoying hum, so an earth loop between lathe and DRO may cause electrical noise which may give odd readings.

Regards Nick.

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