a good use for a HP 7475A

One good use for an old plotter is to draw circuits for etching
circuit boards. a Sharpie or better pen will place the ink/resist
before etching the copper.

this is one of the most common used for these old units. at least
among hackers.

just for kicks, you might be able to drop some acid from the pen. The
kind that cuts glass and etches glass. I think some sort of floride
acid ??? real nasty stuff though. eats through lots of stuff and is
expensive.

I have 5 myself and they just are taking up space. The motors are
too small for any cutting use. IMO.

Dave

--- In CAD_CAM_EDM_DRO@y..., "eggpoodle" <eggpoodle@y...> wrote:
> I am new to this group, and have interest in making a CNC for use
in
> architectural model making and possibly wood work (canoes, curved
> things)
>
> I have access to about 9 Hewlett Packard 7475A pen plotters (11X17"
> capacity, 6 or so pens). Are these units useful for making a small
> machinge, perhaps using a dremel or similar for cutter?, or are the
> motors too light duty for the job?
>
> Also, any idea what a fair price is for them if working? (they are
> pre-1990, and use an off-base serial connector)
>
> I'll watch this thread, and can be directly emailed at hdesign@i...