The DRO

Having chosen an excellent SINO lathe DRO from Allendale Electronics* (Machine DRO) I was confronted with the task of fitting it to the Long Bed Super 7 and immediately encountered scale siting issues.

All the x-axis installation options were problematic in one way or another -

Siting the scale the front of the slide puts the unit in the way of the work, chucks, drive dogs and chips, with it on the back of the slide it's in the way of the tailstock, limiting the proximity of carriage & tailstock, extended out at behind the bed it is out of the way of the work but somewhat vulnerable.

 

Discounting these options a fourth way was needed.

Using some ground round rail, linear slides and end mounts for the rails I constructed a precision slide.  

By mounting the scale to the rail ends and the reader to the slide a self contained unit was created which works on or off the machine, one bolt and an L bracket hangs it off the back of the carriage and a simple T-Nut and link rod arrangement to the cross-slide accurately and repeatably transfers motion.

Fitting or removal is now achieved in a minute with 2 hex screws and a wing nut.

X-Axis encoder and scale unit  shown in place at the rear of the lathe, a bump which could destroy a conventionally mounted scale and/or encoder in this location will merely bend the easily replaced mounting bracket

 The Z-Axis

A taper attachment sees occasional use on this lathe so the standard installs for the Z-Axis were not an option, an enlarged version of the X-Axis install had some merit but the Long Bed Super 7 was just too long for a pair of round rails, sag and flex would be a problem.

 

A single Supported Round Rail with two Linear slides was sourced from Zapp Automation*.

Two outriggers (with sealed bearings for wheels, running on the support extrusion) were fitted to the slides producing accurate linear motion with no rotation using just one rail.

 

The Linear Scale and cover are mounted to the rail base extrusion, the reader is linked to the slide unit. Two wingnuts on captive threaded studs in the rail base support the whole assembly on a pair of L-Brackets screwed to two of the standard holes in the back of the Myford bed.

Motion is transferred to the slide through a set of angle brackets provided with the scale, a machine screw fitted to the top bracket contacts the carriage, a tension spring holding it in firm contact.

 

Z-Axis encoder and scale in place at the rear of the bed, a spring clip and two wing nuts allow rapid fitting andremoval of the entire unit, two further screws release the L-Brackets from the bed leaving the lathe free for the taper attachment.

 

Construction and installation is entirely from off the shelf DIY shop nuts bolts & screws and easily available Aluminium Angle materials, requiring only basic benchwork and drilling to complete.

 

* Magic 9 Design Ltd has no connection with Allendale Electronics or Zapp Automation except as a very satisfied customer.