Re: [CAD_CAM_EDM_DRO] Project on a miniscule budget

milespaul2004 wrote:

>Here's one to challenge all of you!
>
>I need to put a 0.1875" square hole along a 1.25 inch length of a
>0.250" square BMS bar. I need this hole to be a lapped or precision
>fit on 0.1875" square bronze slipper. Fabrication using silver
>soldered joints is a possibility but so far I have not been able to
>produce these components with the fine finish I need for the job...
>An EDM machine came to mind and I would like to have a go at making a
>simple one if that's possible.
>I am retired here in the UK and have little spare cash but as an ex
>audio engineer and film sound recordist I do have some knowledge of
>electronics.
>
>
>

>http://jelinux.pico-systems.com/edm.html
>
>

This is about as simple as you can get. You can use square brass tube,
we can find
it in hobby shops here, as the electrode. Apply fluid from the top to
flush the
debris away. I have used alum-tap, some kind of hydrocarbon tapping
compound
as an EDM dielectric. Water seems to electrolyze briskly, even at 30 V,
but your
water may have less dissolved salts. I didn't try distilled water, some
people
say this works well. The RC system is slow, but if you can rig a scheme to
feed the tool slowly, like .0001" per second, it will work.

Jon