9x20 Lathe DRO X-axis Scale
Last updated on Sunday, September 07, 2014 06:02:35 AM Eastern US Time Zone

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Brackets, Scale, Alignment, Cables & Mechanical Linkages

Brackets


-20 tapped mounting holes on the back of the carriage & the lathe bed (not shown).


10-32 & 1 (top, center)
-20 tapped mounting block.

L-channel mounted to block to hold & protect the scale from impact/debris.


A very sturdy structure.

Scale

Six-inch, vertical style scale mounted to L-channel; same scale style as the mill Y & Z scales.
I soldered a 100F 10v tantalum capacitor across the battery leads of the scale.


6-32 drilled & tapped (50% threads for steel) in the cross slide table end.
This particular tap handle has a guide that mounts into the drill press chuck.

Alignment

Measured scale runout & shimmed as necessary. The reach of the 2" dial helped.

Cables & Mechanical Linkages

Brackets & connector rods (6-32 screws) shown for the X & Z1 axes scales. The single pivot points of the
connecting rods allow easier alignment & the round rods do not snag debris as easily as flat surfaces. Since
the scale end brackets are slotted, the vertical adjustment was easily achieved by moving the scale to one
end, tightening the mount nut then moving to the other end & tightening the nut. The wires hang off the bracket
end which keeps them free to move with the carriage. All cable plugs are held in place with a spot of hot glue.


Cross slide fully retracted showing how all the brackets clear each other.


Installed rubber washers on the scale linkages allowing a little floating to reduce the strain on the transducers.

The RF-25 mill's free-floating Z-axis design works so well that now all of my mill & lathe scales
are attached at only one end while the other end remains captured but loosened to allow floating.
This approach greatly reduces minor out of alignment induced stress on the transducers. This
design also helps to reduce DRO jitter as does a clean, deburred transducer with NR capacitors.



It was good that my DRO design kept the transducers & linkage positions high, thereby providing
enough clearance & enabling me to install the 2.5 longer variable speed DC motor at the lower position.

Brackets, Scale, Alignment, Cables & Mechanical Linkages

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