Metal Disintegration Machine dissolves broken bolts.
 

I am trying to drill a harmonic balancer/pulley bolt out of a Mitsubishi truck crankshaft that has broken off below flush in the recessed hole. common problem for these 90 era trucks.

after the first hole, i broke the easy out(square fluted tye) off in the hole, and am now drilling the hole next to the broken easy out so i can break the new craftsman easy out off next to the first.(LOL)

so whikle i am drilling and sharpening the bits, i get a lot of time to research other peoples methods of dealin with broken bolts. So i read about this Metal Disintegration machine, which i think accelerates the oxidation process of metal. anyone have real life experience with this device?

is ther one in Kansas City or nearby?:)

thank you all for the tons of advice.

tom

Electro discharge machining (EDM) is what its called. You basically burn out /vaporize the broken stud and it leaves the threads intact. Its the best solution though not cheap. Also might be hard findind a place near you that can do it. Its usefull also because it will burn as easily through the EZ out as it will the stud.

How does it work??? How does it not harm the metal around it??

EDM machines operate on a spark erosion principle. for removing a broken bolt the item would be setup with a carbon electrode plunging straight down in to the hole. This is all done in a bath of some kind of non conducting oil or water mixture. The electrode plunges down for a few moments and then raises briefly to flush out the eroded particles and plunges again. This up and down movement gradually works its way down going a few thousandths of an inch further every time. The electrode is eaten away also but at a slower rate because of the carbon material. The electrode used would be sized to the minor diameter of the threads of the broken bolt. When its all done all that remains of your bolt is basically shaped like a spring an can then be picked out of the threads in the hole.

How do I know? - I'm in the Tool and Die trade and this is one of the tools we use. It is also possible to EDM threads into a Hardened steel object using a setup where the electrode is rotated as it is inserted and retracted.

If anyone is interested there is also a tool called a Wire EDM where the electrode is a brass wire. The wire is .008in dia and cuts a .010in slot following a CNC tool path to create incredibly accurate cuts in any metal or conductive material. Like a super accurate bandsaw.

This is the kind of high tech jobs that we are losing everyday to cheap offshore competition

It sorta sounds like that tool won't help out the average Joe. Considering that you'd have to pull out the engine and dunk it in a big tank of 'water' :p

That second machine almost sounds like a plasma cutter on steroids.

Call around your area to find a shop that can remove broken bolts. I called a BMW dealer to find out who they use for broken bolts for my sister's BMW and they referred me to a shop that can EDM and do just about anything that has a hole through it (the business is called the Hole Shoppe) but its probably 1500 miles from you.

A few months ago I spent 2 days and incalculable frustration trying to EZ Out a lower than flush bolt out of the A/ Compressior (the top bolt that mates the housing to the car). Finnaly I gave up doing it myself. Local machine shop got it out in 20 minutes for $10.