RE: [CAD_CAM_EDM_DRO] cheap edm tap buster?

Yes Jon, Paraffin is Kerosine, over there, aviation fuel, what they fly jet
aircraft on, though I prefer Avgas in my car what they fly the old prop
planes on.

Nice cheap and readily available. As a liquid in a bucket you have to get it
really hot to vaporise before you can burn it, or you use a wick to vaporise
it.

I suppose for EDM use, it's either keep the amount small so that if it
catches on fire, it's one puff and all burnt up, or keep a large quantity so
it keeps cool.

On the commercial sinkers they pump the kerosene through filters and a
complete cooling plant. If you push the current up too much you can get
quite some nasty smoke puffs.

AS you know they also have quite fancy power generators and automatically
withdraw the probe on a short, a probe like yours they actually rotate and
bump up and down, the current controlling the rate they bump at.

I have never worked on any of the old simple sinkers, as an electronics
engineer I was dumped in on CNC stuff, 'hey mate can you fix my machine
cheaper than the manufacturers engineers'.

I am amazed at how simply you manage to pull this off. I don't have the need
or room for a full CNC EDM machine, but I do get broken taps and things
where I could do with a better codge to get it out. When the mill is
finished and running as a mill, I am going to have to make up a simple EDM
rig and play I think. May even reserve an input on my G100 to control short
circuit lift off.

Thanks for the heads up Jon



Regs Mark



Dr. Mark Vaughan Ph'D. B.Eng. M0VAU

Managing Director

Vaughan Industries Ltd, reg in UK no 2561068

Water Care Technology Ltd, reg in UK no 4129351

Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH, UK.
Phone/Fax 44 1872 561288

_____

From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Jon Elson
Sent: 11 March 2007 05:26
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] cheap edm tap buster?



Mark Vaughan wrote:

>I note here Jon had problems finding a suitable fluid.
>
>In the wire machines we use deionised water, which is deionised by pumping
>it through resin after it comes out of the filters.
>
>
>
>But on the EDM sinkers we use paraffin, and a fire extinguisher just in
>case.
>
>Paraffin is quite cheap, and readily available. I have never seen a machine
>go up in smoke, but if you play with this I would suggest to be very
>cautious.
>
>
>

Because this thing has voltage on the electrode essentially all the
time, it needs very
clean water or it will foam like crazy with electrolysis. I couldn't
get clean enough
water, but then I didn't try real hard, either.

The stuff I was using was some sort of hydrocarbon, but either had a
fire suppressant
in it, or just had a really low vapor pressure. I did get one "puff" of
flame one time
when the fluid level ran low, although I had sparks ejected through the
fluid all the
time. So, I would be real cautious with flammable solvents.

The British term parrafin is something close to the US varsol, kerosene,
etc. A low-evaporation
paint thinner might be good.

Jon





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