9x20 Lathe DRO

9x20 Lathe Digital Read-Out (DRO)
Last updated on Monday, August 12, 2019 05:15:49 AM Mountain US Time Zone

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9x20 Lathe DRO, DRO Wall Mount Bracket, DPU-550 Daughterboard Upgrade, Lathe Work Light

9x20 Lathe DRO

The lathe is at the upper limits of weight & size that I could safely move down a hill & into my lower level walkout.
X-axis scale is mounted off the back of the carriage so there is no interference with the tailstock. Both L-channel
mounts effectively protect the scales from impact, fluid & debris. For my particular setup, the lathe is still the same
distance from the wall as before the scale addition. DRO is mounted onto wall. Its location positions the DRO
away from any cutting fluid spray. When the X-axis scale is set to the diameter mode, its far left decimal is on.
The tachometer is indicating 637 RPM on the Z2 display. The auxiliary port must be first set to ON in setup, then
tachometer & SFM are activated using Functions 7 & 8, respectively. Scales directions & polarities must be
correctly defined in the DRO setup for several of the functions to work properly.

DRO Wall Mount Bracket

The arm pivots at both ends. Cement screws used as wall fasteners. Since the mount is so rigid, there is no
need to offset the bracket like that done for the Mill DRO. Plugged fastener access holes with black, 5/8" diameter,
snap-in plastic caps. Cables are spiral wrapped for protection. Adding a deep red filter enhances the LED display
contrast. The five LED indicators have circular (punched) red filters, placed in the enclosure cover, too.
The DRO is plugged into a surge protector.

DPU-550 Daughterboard Upgrade

The DRO-350 has been upgraded with the DPU-550 daughterboard & overlay for enhanced capabilities.

DPU-550 OpenDRO User's Guide Rev 5 OpenDRO Supplemental Guide OpenDRO Software Upload Manual OpenDRO

Scales' directions & polarities must be correctly defined in the DRO setup for
several of the functions to work properly. Refer to page 38 of the Open DRO Supplemental Guide.

DPU-550 for the 9x20 lathe showing 146 RPM.
For the DPU-550, a 74LS14 Schmitt Trigger was needed to make the tachometer work reliably.
Since any input can be displayed on any line, the RPM is assigned to the middle line & Z1 to the bottom line.
The X-axis far left decimal is illuminated indicating it is in diameter mode. Of the numerous features, some include:
ARM-7 CPU, fractional input, reverse Polish calculator, high-precision displays, large storage & USB interface.

With the variable speed DC lathe motor modification, I can now dial-in speed to
display a specific SFM (e.g., 200) which varies instantaneously with diameter changes.

Click on linked thumbnails

Lathe Work Light

All cable plugs are held in place with a spot of hot glue. Don't let any volatile liquids seep in behind the
DRO's overlay, it might damage the silkscreen. I accidentally splashed mine with isopropyl alcohol while on
the bench, causing damage. The overlay has since been replaced. It pulled off but it left quite a bit of sticky
residue to remove since I had used the suggested (excellent) 3M Super 77 adhesive for mounting.
The newer upgraded overlay for the DPU-550 has double-sided tape applied in the proper areas, only.
An upgraded display mount design allows better pivoting positions & incorporates a cable tie strain relief.

Installed a galvanized steel extension plate to move the light's magnetic base towards the back.
The plate is an electrical-box cover.

An upgraded task/machine work light (USA) for the Jet 9x20 lathe setup.
It uses up to a 100W (maximum) halogen or incandescent lamp.

Double-walled shade with a finned aluminum heat sink keep it cool to the touch & extends switch life.
The lamp's head can be directed more effectively than the previous light.

Discarded the magnetic base & bolted directly to the cross-slide T-groove. The mount uses 6mm cap head
bolts with steel T-nuts. The original base bolts were 1/4-20 but the 6mm bolts used here fitted perfectly.
Now the lamp is very secure when moving the head around & there is no magnet to attract metal swarf.