Building a Super-Simple EDM or Metal Disintegrator

The book "The EDM How-To-Book" by Ben Fleming is more involved than what you described but it is still down at the home shop DIY level. You might review it for ideas. I don't recall for sure but I probably got it from Lindsey Technical Publications.

http://www.lindsaybks.com/.

Bruce

Bruce,

I understand Lindsay is out of business. Do you know of any other sources of the kind of books they used to print? I loved 'em, but apparently all of us together couldn't love them enough to get them through these times.

Your spirit may be in the right place.

BUT.

I am bothered by people wasting their time reinventing the wheel.

The power supply needed is high voltage, current limited. Available on Ebay, cheap.

Wire or other erosion conductors are industry standard.

So is the dielectric liquid.

Now, what exactly you wanted to improve?

If you do it iust because you want to, go ahead, have fun.

This is not a waste of time pursuit.

An inexpensive, make-it-at-home EDM with limited abilities (mainly to help remove broken taps and drills from metal projects) is a reasonable goal. My target audience is Model Engineers . . . people who build operating miniature engines, locomotives, etc. They are not electronic technicians and are not about to go off and spend hundreds of dollars and lots of time building a piece of equipment they would only use occasionally.

So, I'm not interested in improving EDM state of the art but providing an affordable way to remove a hardened tool from surrounding metal without destroying what may represent hundreds of hours of work on a model.

I am told by old-time mechanics that a commercial version of this machine also powered by a 12 volt battery, was once available for use in automobile garages. Commercial 'Metal Disintegrators' are still available but are seriously upscale and pretty much out of the financial reach of an automotive garage. Looks like another case of the technology walking away from a market.

This machine I've built works already. I am merely attempting to optimize it. Seems reasonable to me as it will to my readers.

I hope you "publish" here as well as I would also like to build such a cheap unit.....as I don't have the money for an expensive unit either.

.....and even if I did have the money, my Scottish blood would prevent me buying it......

I will publish it in our free newsletter as well as the magazine.

You can subscribe to the newsletter by going to our Web site, www.modelenginebuilder.com and signing up.

The downloadable PDF file should be available by the end of this Month. I'll send a short e-mail to all newsletter subscribers when it is.

I've set the newsletter up to be a downloadable PDF rather than pushing it to all subscribers as it cuts down on the size of traffic and not every issue is interesting to every subscriber.

Many thanks.

I am sure that I won't be the only one taking advantage of your kind offer.

Now that I'm sort of recovered from having a heart valve replaced, I'll get on with publishing the EDM in the newsletter. Expect it before the end of the month.

With these elaborations it looks that much better. Please, count me in.

Aye ... am with you! I, too, would like to see the details of the finished (or even semi-finished) design. I MIGHT find a way to improve it for my use, but probably not. And I certainly would like to own an affordable one I built myself.

I don't remember the details; One of our field guys used to make one using a vibrating marker tool instead of the coil. Same deal with the battery. I never got interested enough to pursue the idea.

A few more resources

http://modelenginenews.org/meng/edm/index.html

skipping to end

http://modelenginenews.org/meng/edm/p6.html

even though I hate the way yahoo handles sign in

http://tech.groups.yahoo.com/group/EDMHomeBuilders/?yguid=177091715

Thanks but those two approaches have been around for many years now and the two designs have problems. Not only with their technology but just the fact the Model Engineers are not electronic technicians and have little patience or training for electronic projects.

far more than 2 approaches on the yahoo group

this may answer your question

http://tech.groups.yahoo.com/group/EDMHomeBuilders/message/3413

I had some sort of brain wave last night. The battery power is OK but the battery gets discharged rather rapidly at the approximately 40 amp discharge rate.

However, I have a perfectly good MIG welder sitting out in the shop that will happily deliver 90 amps (it is a small 110 VAC input model). It has a massive copper-wound transformer and should be capable of sustaining 40 amps for a fairly long time. It does have duty cycle limits but they are fairly mild at 40 amps.

Granted MIG welders have a constant voltage style power supply and the open circuit volts are something like 20-30 VDC, but this should work ok. I'll try it in the next few days.

If the 90 amp welder won't work, I have a 160 amp in the shed.

Any thoughts? Other than the MIG means the EDM isn't portable.

Greetings.

If I remember correctly Lindsay Publications had a book on building this.

Oly