Advice on DRO mounting on Myford VMC

[Brian O’ConnorParticipant @brianoconnor49474]

Hi John,

The problem with mounting the Z axis scale on the VMC is that the pillar slopes in towards the top. I got over this by simply drilling and tapping into the pillar and using a screw as a standoff. I can't remember what I did at the bottom, probably a short sloping spacer. I've just taken this photo of it.

As for the Y axis, I did consider the loss of travel when mounting it behind the table, but after nine years there have only been a few occasions where I could have done with some extra room but have always managed to find a way round the problem.

Edited By Brian O’Connor on 02/10/2022 18:16:08

[John DParticipant @johnd]

I thought I’d drop a quick update on progress with the DRO install.

The Y axis is done, the knee Z axis is done. I am procrastinating about whether to go front or rear for the x axis. I don’t mind losing the stops but don’t like the vulnerability of having it on the front – but equally I don’t want to lose y axis travel unnecessarily. Also, does anyone know the angle of the dovetail on the front of the table? Or better still where dovetail nuts are available from (I could just by a dovetail cutter I suppose)?

I decided to go with the idea of a combiner and an addition Z axis encoder on the quill. It will only be tiny but a nice addition and not much more money thanks to Tony and Jo at M-DRO.

I’m looking at no-drill mounting options for the quill scale and thinking a machined plate to replace the cap on the left of the head and then a mounting on the top inch or so of the existing scale for the encoder.

Edited By John D on 16/10/2022 18:25:02

[Martin KyteParticipant @martinkyte99762]

Front mount is best for the X. You should already have the captive nuts on the end of the stops which you no longer need. The solution to the Quill is magnetic strip encoder mounted on a plate stood off from the quill scale.
Hope this helps.

regards Martin

[John DParticipant @johnd]

Thanks Martin. I’ll go front for x as you suggest. I’ll cut a large chamfer on the back of the L bracket that the encoder mounts on so it clears the oiling points and that way the rail can sit nice and flat just above the two oiling points.

i don’t have any captive bits for the dovetail so hoping I can find a ready source for them. Does anyone know if all the variants of these VMC have the same dovetail size in the front?

[Nigel Graham 2Participant @nigelgraham2]

It's not really practical to fit the scale on the back of the table. There is no room for it without losing a fair bit of cross-travel; and it would be in the worst place for swarf and coolant. This leaves you little alternative but to lose the stops as it hogs their slot, short of having to build a rigid off-stand for it.

That I found the biggest drawback.

I do not believe this common idea that once you have a DRO you no longer need the stops. If you are making a lot of repeated cuts, such as in milling a large recess, it is far easier to use the display to set the stops then work to them, rather than keep having to look up at the display.

I prefer to augment the machine's features, not just blindly replace them.

In fact I spent a little while yesterday examining my VMC to assess how I can make not only new long-travel stops, but also cross-travel stops it lacked as original design.

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