Re: DRO with surplus plotter parts

> Has anyone tried making a DRO using the guts of surplus pen plotters like the HP 7550?
>

Not exactly, but I did cut my trumpet bell mandrel using a DRO, one
axis of which was salvaged from an HP deskjet. It was something like
a 2016 cpr (don't remember exactly) rotary encoder stacked on the
little motor that moves the printhead. I couldn't get it off the
motor, so just coupled the whole thing, motor included, to the
crossfeed screw. (no, the motor isn't nearly powerful enough to move
it, allthough it might be usable as a tachometer in a servo setup).

The reader module is apparently similar to the (suprise) HP ones sold
by US digital - so I hooked it up exactly like the HP reader head that
came with my linear strip.

Plotters might include similar encoders - although it's possible some
are open-loop stepper systems with no feedback other than a home sensor.

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
30 Griswold Street, Cambridge, MA 02138
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