----- Original Message -----
From: <Cougarjack@aol.com>
To: <Richard@fv623.demon.co.uk>
Cc: <mil-veh@uller.skylee.com>
Sent: Saturday, May 26, 2001 11:40 PM
Subject: Re: [MV] M37 axle-end studs/bolts
Good advice from Jack and I make no apology for re-copying it in full, we
have done very similar things with good success.
> A slick trick is to obtain a left hand helix drill bit. use this to drill
into the center of the broken stud end, using your reversible drill motor.
> It helps to make a drill guide from a piece of scrap steel first. (the
thicker the better) You lay out two holes so the guide can be bolted to
two of the hub holes, straddling the broken one, and a third one right in
line with the broken one. Drill the third hole so that the drill you'll be
using will just enter it. If you lay out carefully, the third hole will
force your bit to cut right down the center of the broken stud.
> When you have a good stable hole established, remove your plate, bear down
hard on the drill, causing it to snag, which will usually turn the broken
stud out. It takes a bit if finesse, but it usually works quite well. A
broken drill bit is way easier to remove than a broken screw extractor. The
new spiral cutter type rotary tools have bits which will cut a drill stub
like butter.
> Another trick I learned while working as a gunsmith is to use Aviation
Permatex liquid as a drill lubricant when drilling hard steel. It keeps the
drill sharp and helps keep the chips from packing, which is the usual reason
for breakage. try it!
>
I will have to see what this is called here. For example, a recent post
told us of the efficacy of Loctite (we like them, good stuff) "Extend 754"
as a rust converter, you wont find this on the UK website and I had to ask
them direct, its called "Rust Remedy" here and I am shortly to "evaluate" it
on the more serious bits of a FV623.
There is a device like an Ez-Out but is square section rather than a
left-hand spiral, these are driven into the pilot hole and seem to take far
more grunt than an Ez-Out before submitting, the disadvantage being that the
broken fastener is necessarily swollen slightly by driving the tool in.
The only time an Ez-out has worked for me was on an old and rusted spark
plug that sheared off on the body, this left a ready made and centralised
hole of generous proportions that would admit an Ez-Out of substantial size.
Normally its the 1/4" studs or similar that we break and this precludes the
use of an extractor of suitable strength owing to the size of pilot hole
that can usually be made.
In these instances it is often better and quicker to simply drill the whole
lot out oversize right off and fit a Helicoil insert, after fiddling about
with the other techniques its often the enforced final solution.
Richard
Southampton - England
This archive was generated by hypermail 2b29 : Tue Jun 05 2001 - 23:18:39 PDT