Author Topic: Poor Man's EDM  (Read 8323 times)

Offline Bernd

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Poor Man's EDM
« on: June 28, 2011, 08:10:16 AM »
Found this on the Mial List I belong to. Might help out those small holes that need to be dilled through hardened material.





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Offline David Jupp

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Re: Poor Man's EDM
« Reply #1 on: June 28, 2011, 08:41:31 AM »
Now all those incorrectly made 123 blocks can be fixed !

Offline Bogstandard

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Re: Poor Man's EDM
« Reply #2 on: June 28, 2011, 08:47:16 AM »
Very interesting Bernd.

I'm always interested in easy ways to do things.

I have seen all sorts of home very complicated builds for EDM machines over the years, some requiring degrees in electronics, and many thousands of pounds worth of precision machinery, it would have been cheaper to go out and buy a second hand (or even a brand new) commercial unit.

I actually worked on that principle in the late 60's, when I was just a lad, but being used for an arc welding tool that could be run off your car battery.
It self struck by flicking backwards as you touched the stick onto the job, then forwards again, continually striking an arc and depositing metal. Because it wasn't a continuous burn process, a lot less heat was generated and you could actually weld paper thin corroded up steel sheets (just what cars of the time were built from).

The idea was actually put into production a few years later here in the UK, someone might even remember them. Not produced by me BTW, I just got the very basic prototype working. But it is basically exactly the same as the chappie in the vid was doing, but he uses gravity for the forwards motion, whereas I used a light coil spring, the same as a standard sort of solenoid, but great deal more amps. My coil was made from fairly thick copper wire wire wrapped in glass fibre tape for insulation, and it got very hot, but it worked for a run of about 6", then let it cool down a bit before continuing.

If anyone is interested in making a low voltage welder, I am sure I could remember enough to knock up a sketch to get you started.


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Offline raynerd

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Re: Poor Man's EDM
« Reply #3 on: June 28, 2011, 08:57:30 AM »
There is a chap who demo`s spark errosion at the last few Harrogate shows and I also saw him at the midlands show. I don`t know too much about it but it looked a fancy setup, I presume similar to the one in the video - but I could be wrong!  Very interesting - thanks for posting. 

Offline crankshafter

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Re: Poor Man's EDM
« Reply #4 on: June 28, 2011, 11:11:51 AM »
I want one  :drool
Hey Bogs make us a nice C.O.C of your EDM.
Here is an other simple EDM.

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&version=3"></param><param name="allowFullScreen" value="true"></param><param name="allowScriptAccess" value="always"></param><embed src="
&version=3" type="application/x-shockwave-flash" allowfullscreen="true" allowScriptAccess="always" width="640" height="390"></embed></object>

Offline Bogstandard

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Re: Poor Man's EDM
« Reply #5 on: June 28, 2011, 11:19:32 AM »
Quote
Here is an other simple EDM.

And made by a simple person who uses a micrometer as a g clamp :doh: :doh: :doh:
If you don't try it, you will never know if you can do it.

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Rob.Wilson

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Re: Poor Man's EDM
« Reply #6 on: June 28, 2011, 03:54:32 PM »
Nice one Bern  :thumbup:

Cheers for showing ,,,,,,,,,,, i will surly make one when i next snap a tap in a job  :dremel:



Rob

Offline John Hill

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Re: Poor Man's EDM
« Reply #7 on: June 28, 2011, 04:07:09 PM »
Very interesting Bernd.

I'm always interested in easy ways to do things.

I have seen all sorts of home very complicated builds for EDM machines over the years, some requiring degrees in electronics, and many thousands of pounds worth of precision machinery, it would have been cheaper to go out and buy a second hand (or even a brand new) commercial unit.

I actually worked on that principle in the late 60's, when I was just a lad, but being used for an arc welding tool that could be run off your car battery.
It self struck by flicking backwards as you touched the stick onto the job, then forwards again, continually striking an arc and depositing metal. Because it wasn't a continuous burn process, a lot less heat was generated and you could actually weld paper thin corroded up steel sheets (just what cars of the time were built from).

The idea was actually put into production a few years later here in the UK, someone might even remember them. Not produced by me BTW, I just got the very basic prototype working. But it is basically exactly the same as the chappie in the vid was doing, but he uses gravity for the forwards motion, whereas I used a light coil spring, the same as a standard sort of solenoid, but great deal more amps. My coil was made from fairly thick copper wire wire wrapped in glass fibre tape for insulation, and it got very hot, but it worked for a run of about 6", then let it cool down a bit before continuing.

If anyone is interested in making a low voltage welder, I am sure I could remember enough to knock up a sketch to get you started.


John
John, I remember those 'staccato' welders being advertised and at the time I wondered if a spot welder would not have been practical on a car battery.  Unfortunately the staccato welders got a very poor reputation here as they were promoted to people such as farmers who would have then tried to weld half inch steel with them.
From the den of The Artful Bodger

Offline Bogstandard

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Re: Poor Man's EDM
« Reply #8 on: June 28, 2011, 05:21:33 PM »
John,

They actually gave a weld similar to joined up tack welds, a very small deposit at each strike, but very little actual penetration. They worked OK on something like 1/16" or maybe 1/8", but definitely no thicker.

They died a death after a couple of years on sale. Just like the bowler hat with sleeves.


John
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Location - Crewe, Cheshire

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Offline Corvus corax

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Re: Poor Man's EDM
« Reply #9 on: June 30, 2011, 10:37:43 AM »
I have to say that something like that would be perfect. I have a regular arc welder for anything over 3 mm anyway. But thin sheet welding is next to impossible with it.