I only know the initials. Not sure what they stand for. Can someone describe what exactly this is if someone knows.

Is it somekind of laser?

I thought broken studs made engines junk but...

EDM to the rescue!

Electrical Discharge Machining. It basically is the use of an electric current to remove metal. Although it's an inexact analogy think of it as electroplating in reverse.
You make a carbon electrode of the "male" pattern either with CNC or other means, and this is used to munch a matching "female" shape into the metal to be machined, one spark at a time. It is done underwater, and is kinda neat to watch for a few minutes. It's accurate, but not quick. The sparking pulses are cycled and the watery fluid helps keep things cools and clean.

I'm maybee way off beam here, but I beg to differ. Chevtown must have been at an informal street racing meet where somebody set out the 1320 ft mark with a surveyors EDM/Theodolite.

That EDM is Electronic Distance Measurement. Survey Theodolites are fitted with an infra-red wave generating device which sends out a specific wavelength of electromagnetic radiation to a target made of crown glass. The infra-red wave is focused to a point which the beams the wave back to the unit that sent the signal. By measuring the phase separtion between what was sent, and what is returned, the distance can be measured to the nearest hundreth of a mm ( 40 thou of an inch), even for distances of up to 6 km ( 4 miles+).

I did land surveying for 2 years and used it a lot. In the old days, we just fitted a external EDM device ( our beloved DI1000) to the Wild T1a theodolite we used. Then we'd shoot to the target, and measure the return signal, and get the readings. Much better than using a fibre tape or metal "chain".

These days the Japs build self contaned things like Sokitia Set 4's etc which cops use after accidents, or Civil engineers use for complicated set out where an engineers level aint gonna cut the mustard.

My 2 cents. Could be crap, could be fertilizer!
Yes, XECUTE, it may be more accurate. But can it perve on chicks like the good old builder's level? :nono:
Yes Addo, it can see right through them with x-ray vison. That's the best part! The EDM part comes with a 28X or greater magnifcation eye piece. As Whittey said
XECUTE: Please, if you know that girl in the 'babe patrol' pic, could you feed her a cheeseburger? She looks like she could use a couple.....

With 28 X magnification, small topographical features can become quite significant!

ooopps, watch out for the bolts of lightening! :shockin:
:devilish: You rotter! Mine only goes to 24×... Then again, I've got hair AND a suntan... :LOL:
OK, technical question,
EDM for broken stud removal was explained, how does the EMD- theo system work and is it better at removing broken studs, bolts and taps.

The broken studs were the ones discussing it.

There's also a "wire EDM" system which simply uses a wire as the electrode rather than machining a piece of carbon to the desired contour. It is more likely to have been used for stud removal since "one size fits all"
Had one at Beech for Apollo Project machine shop, if the piece being removed conducted electricity it would eat it, slow but gone.
It would even eat carbide bits, exotic metal taps, if the conductor was machined to the right size and centered over the hole, it would eat through, taking out the center of the tap leaving four "racks" of cutting teeth.
That EDM is a crazy kewl deal man.

It worked like a charm and looks like the broken stud was never there.


Only $20 bucks including taking off one exhaust stud that was stripped and retapped all 12 holes for the 7/16" rocker studs...that place rocks man.

EDM isn't a new process- I was cleaning up some paperwork in an old office at my last job, and found a salesman's brochure on the process. I think it was dated 1962 or 63. Seems pretty cool, but really is best for drilling small holes in thin stock. They had cutaway pictures of a piece of wire that had a hole drilled into it lenghtwise, first with a #80 drill (kinda nasty looking hole), and then with the EDM (nice and clean). IMO, though, the best method for removing broken studs would have to be sonically cracking them.

Is sonic crackling kosher? Seriously, how does this work on a stud embedded in a block?
Not sure exactly, but it is similar to sonic welding on plastic and aluminum. Basically, you have a computer control device that creates a resonance in a solid piece of steel, called a horn. This piece is tuned to create the best resonance for a certain material at a certain hz. The horn is touched to the piece, and if it is set up to weld it, the vibrations heat up the material enough to cause fusion. If it is set up to remove material, the resonance is set to affect the stud or piece that needs to be removed, and not the surrounding material, as every material has a different hz that it is affected by. The horn is touched to the material, and the material disintegrates. It's a pretty cool process, but I wouldn't recommend being in the same room while it's going on- not loud, just a REALLY annoying sound.