[Public-List] Battle of the Bolt

[Jeffrey]

Yesterday, after days of heating, spraying, tapping, heating and
waiting..I put the wrench on the one bolt bolt that holds my tiller
head to the shaft, and of course the head came off.  Luckily, there
was just a little stump of metal sticking out past the shaft that
prevented me from removing the tiller head which was easy to grind out
allowing me to remove the tiller head.

Today, with the tiller head out of the picture, I got myself a couple
of screw extraction kits, which of course failed. The bolt isn't that
corroded, it just seems to be part of the shaft now.  When I drilled
the hole for the extraction bit, I drilled all the way through the
bolt since the hole in the shaft also goes clean through.

I could see with a mirror the back side and clear through so with my
hole evenly centered I, drilled out the hole in the bolt larger and
larger, moving up in drill bit sizes to where there's not much bolt
left. I used a chain saw file to further file out the bolt.  I got the
bolt to where just the edges are left. Thinking I could remove this
like a cutless bearing I put a modified hacksaw blade in the hole to
create a split, thinking I'd dork up the threads in the bronze but
cleanly in just the one line. I got the cut finished and still cannot
remove the steel edges of the bolt.

See: https://picasaweb.google.com/lh/photo/dXMZtCcrcLA_ZZuU9tI0bK3GpdfW2x_hlAS0ffzZ0So?feat=directlink

What I'm thinking now is that I should give up on saving the threads.
Just drill it all out and tap threads to the next larger size.
Currently I believe the bolt was 3/8. The hole in front of my tiller
head measures 7/16. Perhaps I could drill this all out to 7/16 and cut
some threads for the new 7/16 size.  How difficult to tap bronze? I'm
not expecting much trouble, but one lever knows.

See: https://picasaweb.google.com/lh/photo/RHegX__ChJC4c-bWAsP_F63GpdfW2x_hlAS0ffzZ0So?feat=directlink

Once (if) successful,  should I use a steel or bronze bolt for this??
It would seem that 7/16 bronze is strong enough, but then again the
bolt is pretty important. Stainless and some anti corrosion substance
like tef-gel??



-- 
Jeffrey Fongemie