FOAK: broken studs

I've seen exhaust studs shear square with the surrounding surface, but
not really inside the hole - anybody seen this before?

I'm trying to work out if my shed of a steed (DR650) has lost one of the
studs or if if it is broken off deep into the hole. If its the latter,
any idea how to get it out (steel stud in an alloy head) given that the
usual tricks like welding a nut to it aren't going to work?

I'm currently hoping that the stud simply vacated the hole and that
they're not screwed in very deeply but this does feel odd...

Oh well, time to order another stud and see how far it screws into the
hole, methinks. That thing needs its own personal bottle of thread lock
anyway, given the way it vibrates.

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, Timo Geusch

LH drill bit.

 

.... in a bench drill, I assume? Bah. Head-off job but there are a bunch
of machine shops around here. Oh well.

 

+1

Worked a charm on the last one I did.

 

Why? I mean, I've never done this, but I can't see why you couldn't
just do it in situ.

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, Ace

Exactly that. Pick a drill that's undersized and go carefully. Have a
look at the swarf that comes out. If it's steel, you've got the remains
of the stud in there, continue. If it's ally, stop.

 

"easy-out"

Its a tapered LH thread with a square end to fit a tap (as in tap & die)
holder.

You have to drill a pilot hole into the sheared stud then open it up with a
bigger drill to fit the best size of easy-out.

As you run the stud through it distorts slightly and helps break the
"frozen" thread, but you only get one go at drilling the stud - off centre
or break out sideaways and you're down the machine shop to have it drilled
out and tapped for a brass insert.

If the stud starts to turn when you drill it, you can probably get it with
one of those JML screw extractors.

 

It's nice to know that Timo's bikes don't change, though they may now
be several thousand miles away ;-)

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, ian field

Which breaks and leaves you with a hole full of hardened steel.

 

Which can just as easily happen to the drill bit used to prepare the stud
for whatever tool is ultimately used.

It just one of those shitbag jobs you don't want to be doing the morning
after.

 

Not IME. The drill's far less likely to jam than something that *has* to
jam in order for it to work. And sometimes you get in the situation
where the damn thing won't turn in either direction until it snaps.

DAMHIKIJD

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, ian field

You'd have to be pretty cack-handed to break a drill bit on a job like
this.

 

Go and find yourself a drill that only just goes into the existing
hole, put a mark on the drill that measures twice the diameter of the
thread, see what happens when you try drilling the damaged thread.

If it takes out any steel you've removed the stud and if it doesn't
then you'd made a mistake.

Once you've done that buy a helicoil set and use it to insert the
head. Drilling, tapping and fitting the insert will probably take the
grand total of about 5 minutes and if the existing threads are fucked
you won't even need to pre-drill it, just tap it and fit the insert.

 

I bet you said the same about cross-threading wheel spindles at some
point.

 

Thread appears to be undamaged so I'd rather not Helicoil it. I'll take
a better look on the weekend once I got all the crap off that prevents a
more thorough inspection...

 

I wouldn't go /quite/ that far, but yeah, I'll never use one again
since discovering LH drillbits.

 

The one time I used one (on a master-cylinder reservoir screw on the
600) it was a fingers-only job -- because drilling the pilot hole had
cracked the inter-metal corrosion.

Anyone know a source of socket-head countersunk 6/32x3/16" screws?
I'm having to use violent taps on the heads of cross-heads holding hard
drives into hot-swap caddies in the RAID arrays of our GRID storage
elements. Luckily force is tolerated as the drives being removed are
deemed dead.

--
Ivan Reid, School of Engineering & Design, _____________ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
GSX600F, RG250WD "You Porsche. Me pass!" DoD #484 JKLO#003, 005
WP7# 3000 LC Unit #2368 (tinlc) UKMC#00009 BOTAFOT#16 UKRMMA#7 (Hon)
KotPT -- "for stupidity above and beyond the call of duty".

 

I'd wager the one's who're complaining about easy-outs snapping off are the
one's who made a piss poor job of drilling the pilot hole.

Can't say I've never done it myself, but I could see what I did wrong and
didn't blame the tools.

 

The problem with an easy out is that it forces the outside of the
thread to expand as you wind it in so it makes the seized fastener an
even tighter fit in the hole.

I'd use one to extract a stud I'd broken by over-tightening but I
wouldn't use one on a stud that was seized in after a few years of
use.

I don't use them because there are better ways of doing the job.

 

I also managed to actually twist one without moving the stuck fastener
once years ago. They were cheap shite TBF.

Some frog must have tried to drill out a stuck chain adjuster on the YZ
years before I acquired it. Even John at Revs who fitted the new swing
arm bearings didn't want to try to undo the damage. So now the one side
has just a long hex head set screw and lock nut in a hole which isn't
threaded or perfectly straight. As it is on the sprocket side I don't
worry too much about it, and as long as I keep the nut nipped up tightly
it passes scrutineering OK.


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