DRO on a Myford Super 7B

I am contemplating fitting a DRO system to my Super 7B as the Digital scale length system I fitted has just died. Have spent a happy 2 hour reading thro, Forums but can,t find a complete description, found a lot of info and some potentially helpful links, (some that don't work) Thinking of using Machine DRO magnetic scales, but would appreciate any up to date help, about the scales used, positions and gib screw/saddle lock solutions. Better still some Photos of a finished setup.

Thanks

I wouldn't advise the EH -05 5 micron magnetic for Y axis, supposedly 0.005mm resolution. Have found on mine to have error in the region of +/-0.04mm repeatability. What that means is take a cut then zero, wind out then back in to zero it wont cut or take lots off. Can have to go in 0.04mm or out 0.04mm creates havoc when threading.

300 series glass would go on the back, me personally would mount a 300 series outboard at the back. If using magnetic it will cover up jib strip adjuster nuts or in front you would have to do away with travelling steady and the like not mention clouting it.

Magnetic ok on tailstock best bit is not having to use the extended nearest length glass available guaranteed to overhang by several inches plus add undue height.

Just completing the same job with glass scales. In essence the Y axis strip IF fitted to the right of the cross slide, interferes with the saddle lock screw and the toolpost rotation lock screw. Not to mention the the tailstock restriction when approaching the crosslide

Using a piece of ~1" x ~12"angle bolted to the back two tee slots. It is possible to cantilever the scale, out to the rear. Assuming you have the room to do it. A single block can then be fitted to the back of the carriage that carries both X and Y reading heads. This approach while seeming precarious is excellent for keeping the scale out of suds and swarf.

I examined three other installations before coming to this solution. Works for me. So far but still tweaking.

I considered DRO for my Myford but I allways thought that it was a little like overkill. The saddle axis was my primary niggle in as far as I would have liked a better way of gauging length of cut to a shoulder etc. This particularly became an issue when I removed the leadscrew handwheel to replace it with a toothed belt for a stepper drive so I could get variable auto feed. My solution came when I bought a Meek graduated handwheel at Harrogate last year.

http://www.homemodelenginemachinist.com/showthread.php?t=17715

This fits where the saddle traverse wheel would normally be and really looks like it fits in as part of the machine. If I did then fit any sort of DRO it would then be on the topslide only and even that I find a bit of a muchness as I can do exactly the same job with the micrometer dial or setting the compound slide over at 6 degrees if I want 1/10ths of a thou.

I try, not very successfully sometimes, to only buy stuff that enables me to do something I couldn't do before or does something in a way which is more pleasing because it gets rid of an annoyance.

The Mill DRO is a classic case which at a stroke removes all the sums with micrometers when going to co-ordinates and makes the mill a duel system machine (metric/imperial) at the touch of a button.

This is not quite the case on the lathe.

I would have to add that each to their own and if it does it for you then get one. The primary product of our efforts is pleasure when all is said and done.

Regards Martin

Hello Martin,

Glad to hear that the handwheel dial is giving good service.

Best regards,

Steve.

I have just completed fitting a two axis magnetic DRO to my Super 7B, it is a subject that has been covered before but I haven't seen it done like this, which of course doesn't mean it hasn't. Anyone contemplating fitting a scale to their lathe may get some ideas from it.

The y axis is straight forward, the scale was fixed to an aluminium flat bar that picks up the taper attachment tapped holes. The cross-slide is more difficult, I did not want to cover the gib adjusters, cross-slide locking screw or loose the carriage lock.

The scale is an EH-05 from Machine DRO, the extrusion that carries the scale has a slot down one edge that can be used for tapped strip. I did not need it so I milled it off to end up with a profile that is 20mm wide. Two counterbored holes allow the carrier to be fixed to a pair of close fitting tee nuts that lock into the cross slide tee slots with grub screws.

I am happy with it so far, the sensor does cover the cross slide locking screw in some positions but it has not been a problem, it could be avoided by mounting the sensor further outboard. I like the fact that the only modification to the lathe are the two tapped holes at the back of the carriage.

Regards,
Michael

Edited By Michael Briggs on 23/10/2015 18:28:07

Edited By Michael Briggs on 23/10/2015 18:31:26

Machine DRO seem to have a fully fitted ML7 on display at the exhibitions they attend. I do not know the differences between an ML7 and a Super 7B, I expect they do.

If you contact them I guess they may be able to help directly.

Short video on fitting DRO to myford kink