A lot of times, the broken-off bolt in the hole is easily screwed out if
only something can get a purchase on the exposed end.
Assuming it is not all crudded up in the bolthole (or solid with red
Loctite), there is no longer tension on the bolt to hold it. A simple dent
made with a small chisel may be enough for a straight-blade screwdriver to
get enough purchase to unscrew the thing.
--Rocky Entriken
----- Original Message -----
From: "Joe Curry" <spitlist@cox.net>
To: "'Randall Young'" <ryoung@navcomtech.com>; <FOT@autox.team.net>
Sent: Wednesday, October 08, 2003 2:20 PM
Subject: RE: flywheel bolts
> I wonder how an impact driver would work on a broken bolt if one uses a
> large Phillips bit and uses a Dremmel tool to create a crtoss hatch on
> the broken bolt!!!
>
> Joe (C)
>
> -----Original Message-----
> From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net] On
> Behalf Of Randall Young
> Sent: Wednesday, October 08, 2003 11:17 AM
> To: FOT@autox.team.net
> Subject: RE: flywheel bolts
>
> > 1. There is a machine called a "tap disintegrator" that uses an
> > electrical
> > discharge through a consumable electrode to destroy a hard part
> > in a hole.
> > Usually a stationary machine, but there are a few portable ones on the
> > market. Disintegrating a tap, or in this case a broken bolt, does not
> > damage the threads in the part. If you can find a shop that has a
> > portable
> > rig, or if you want to disassemble the engine and take the crank in,
> this
> > is one way.
>
> FWIW, there are also plans running around to build one of these on your
> own.
> It's called Electrical Discharge Machining, or EDM for short, and I've
> seen
> several articles published in Home Shop Machinist. I believe you can
> still
> buy the back issues with the various articles, and they also sell
> reprints
> of one of the more detailed articles.
> http://www.homeshopmachinist.net/
>
> One of the articles talked about using the unit to machine out a broken
> and
> corroded steel stud in an aluminum engine block, made it sound easy
> (although slow).
>
> Randall
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