Broken bolt in rear dropout

The bike that I've recently repurposed as my town bike used to have a set
of fenders -- mud guards? -- on it. I took them off a couple years ago,
and when doing so I craftily broke off one of the mounting bolts in the
rear dropout. Don't ask. It wasn't one of my prouder moments.

We're getting some rain and it's time to mount the fenders. But I'm
staring at the face of the broken bolt. And it's not wearing a very
helpful expression.

I have a feeling that things are gonna get messy real fast.

So it's broken off flush with the outside of the dropout, and there's
nothing on the wheel side to grab onto. The bolt wasn't any special
hardened type, just the usual cheap and cheerful kind that came with the
fenders.

Most articles on broken bolt extraction are targeted at extracting larger
ones from engine blocks and such. Anyone have any advice on how I should
proceed with his little one?

--
Mike "Rocket J Squirrel"

"Mike Rocket J Squirrel" wrote in message
...

Most articles on broken bolt extraction are targeted at extracting larger
ones from engine blocks and such. Anyone have any advice on how I should
proceed with his little one?

Is the hole tapped all the way through? Is there much manky thread on the
other side from the bust face? If not, you're in with a good chance because
drilling it will also tend to turn it in such a way it will come out the
other side. Which is what you want :-)

(smaller drill than the threads obviously, and make sure to drill in the
right place. Starting it will be the tricky bit.)

cheers,
clive

On 10/4/2008 7:50 AM Clive George wrote:

"Mike Rocket J Squirrel" wrote in message
...

Most articles on broken bolt extraction are targeted at extracting larger
ones from engine blocks and such. Anyone have any advice on how I should
proceed with his little one?

Is the hole tapped all the way through? Is there much manky thread on the
other side from the bust face? If not, you're in with a good chance because
drilling it will also tend to turn it in such a way it will come out the
other side. Which is what you want :-)

(smaller drill than the threads obviously, and make sure to drill in the
right place. Starting it will be the tricky bit.)


The hole is through-tapped, there is no bolt protruding from the other
side. I see what you're talking about: drilling carefully at a slow speed
might indeed cause the bolt to turn itself through the dropout. But it was
pretty seized, else it probably would not have broken when I tried to
unscrew it.

Where's that bolt solvent when I need it?

--
Mike "Rocket J Squirrel"

Mike Rocket J Squirrel wrote:
The bike that I've recently repurposed as my town bike used to have a
set of fenders -- mud guards? -- on it. I took them off a couple years
ago, and when doing so I craftily broke off one of the mounting bolts in
the rear dropout. Don't ask. It wasn't one of my prouder moments.

We're getting some rain and it's time to mount the fenders. But I'm
staring at the face of the broken bolt. And it's not wearing a very
helpful expression.

I have a feeling that things are gonna get messy real fast.

So it's broken off flush with the outside of the dropout, and there's
nothing on the wheel side to grab onto. The bolt wasn't any special
hardened type, just the usual cheap and cheerful kind that came with the
fenders.

Most articles on broken bolt extraction are targeted at extracting
larger ones from engine blocks and such. Anyone have any advice on how I
should proceed with his little one?

Just use a very small drill bit on a Dremel tool to start. If that
doesn't get it to turn, keep moving up to slightly larger bits. At least
you'll be able to get the hole started with the tiny bit, without
wandering all over. Eventually it will come out. Worst case you'll
damage the threads of the drop-out and have to use a bolt and locknut.

"Mike Rocket J Squirrel" wrote in message
...

The hole is through-tapped, there is no bolt protruding from the other
side. I see what you're talking about: drilling carefully at a slow speed
might indeed cause the bolt to turn itself through the dropout. But it was
pretty seized, else it probably would not have broken when I tried to
unscrew it.

Thing with drilling is it gives you heat, which is good for shifting things,
and if it doesn't manage to shift it you can then have a go at getting rid
of the remaining thin bit by some form of brute force.

(I'm not talking about drilling at a slow speed - there's force on the screw
even if the bit is slipping).

But yes, plus gas on the thing first.

cheers,
clive

Mike Rocket J Squirrel wrote:
The bike that I've recently repurposed as my town bike used to have a
set of fenders -- mud guards? -- on it. I took them off a couple years
ago, and when doing so I craftily broke off one of the mounting bolts in
the rear dropout. Don't ask. It wasn't one of my prouder moments.

We're getting some rain and it's time to mount the fenders. But I'm
staring at the face of the broken bolt. And it's not wearing a very
helpful expression.

I have a feeling that things are gonna get messy real fast.

So it's broken off flush with the outside of the dropout, and there's
nothing on the wheel side to grab onto. The bolt wasn't any special
hardened type, just the usual cheap and cheerful kind that came with the
fenders.

Most articles on broken bolt extraction are targeted at extracting
larger ones from engine blocks and such. Anyone have any advice on how I
should proceed with his little one?



Center the bolt and drill it out. Increase the diameter of the drill
until the inner diameter of the thread. Most of the remaining bolt
thread will fall out. Tap if necessary.

Lou

Mike Rocket J Squirrel wrote:
The bike that I've recently repurposed as my town bike used to have a
set of fenders -- mud guards? -- on it. I took them off a couple years
ago, and when doing so I craftily broke off one of the mounting bolts in
the rear dropout. Don't ask. It wasn't one of my prouder moments.

We're getting some rain and it's time to mount the fenders. But I'm
staring at the face of the broken bolt. And it's not wearing a very
helpful expression.

I have a feeling that things are gonna get messy real fast.

So it's broken off flush with the outside of the dropout, and there's
nothing on the wheel side to grab onto. The bolt wasn't any special
hardened type, just the usual cheap and cheerful kind that came with the
fenders.

Most articles on broken bolt extraction are targeted at extracting
larger ones from engine blocks and such. Anyone have any advice on how I
should proceed with his little one?


Bummer. The only thing is to drill, baby, drill. The first hole is the
critical one. Ideally you want it to be centered & on axis. That rarely
happens. Center punching is good if you can do it. If the face is
protruding, it's worth flattening it. A small bit is best to start,
light pressure, try to keep it from skating.

The last time I did this, I wound up a bit off center as usual. I chewed
out the remaining bolt (small, like yours) with a carbide cutter on a
Dremel (one that looks like a drill with very shallow flutes, slight
taper & rounded tip). I wouldn't obsess too much, if you trash the
threads you can either retap larger or use a nut.

On 10/4/2008 9:12 AM Peter Cole wrote:

Mike Rocket J Squirrel wrote:
The bike that I've recently repurposed as my town bike used to have a
set of fenders -- mud guards? -- on it. I took them off a couple years
ago, and when doing so I craftily broke off one of the mounting bolts in
the rear dropout. Don't ask. It wasn't one of my prouder moments.

We're getting some rain and it's time to mount the fenders. But I'm
staring at the face of the broken bolt. And it's not wearing a very
helpful expression.

I have a feeling that things are gonna get messy real fast.

So it's broken off flush with the outside of the dropout, and there's
nothing on the wheel side to grab onto. The bolt wasn't any special
hardened type, just the usual cheap and cheerful kind that came with the
fenders.

Most articles on broken bolt extraction are targeted at extracting
larger ones from engine blocks and such. Anyone have any advice on how I
should proceed with his little one?


Bummer. The only thing is to drill, baby, drill. The first hole is the
critical one. Ideally you want it to be centered & on axis. That rarely
happens. Center punching is good if you can do it. If the face is
protruding, it's worth flattening it. A small bit is best to start,
light pressure, try to keep it from skating.

The last time I did this, I wound up a bit off center as usual. I chewed
out the remaining bolt (small, like yours) with a carbide cutter on a
Dremel (one that looks like a drill with very shallow flutes, slight
taper & rounded tip). I wouldn't obsess too much, if you trash the
threads you can either retap larger or use a nut.

OBSESSING OFF

Someone hand me my 1/2'' drill motor.

--
Mike "Rocket J Squirrel"

Mike Rocket J Squirrel wrote:
The bike that I've recently repurposed as my town bike used to have a
set of fenders -- mud guards? -- on it. I took them off a couple years
ago, and when doing so I craftily broke off one of the mounting bolts in
the rear dropout. Don't ask. It wasn't one of my prouder moments.

We're getting some rain and it's time to mount the fenders. But I'm
staring at the face of the broken bolt. And it's not wearing a very
helpful expression.

I have a feeling that things are gonna get messy real fast.

So it's broken off flush with the outside of the dropout, and there's
nothing on the wheel side to grab onto. The bolt wasn't any special
hardened type, just the usual cheap and cheerful kind that came with the
fenders.

Most articles on broken bolt extraction are targeted at extracting
larger ones from engine blocks and such. Anyone have any advice on how I
should proceed with his little one?

Drill straight through on center with a 1/8 (3.1mm) bit. Try a screw
extractor. If still not, and if it is truly on center, follow with a
9/64 (3.5) drill. Repeat screw extractor. Clear with m5 x 0.8 tap and
use an anti seize paste next time. Even stainless screws in a small fine
thread are no help as adding salt water makes the end itself oxidize and
lock those in any way.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
** Posted from http://www.teranews.com **

In article ,
Lou Holtman wrote:

Mike Rocket J Squirrel wrote:
The bike that I've recently repurposed as my town bike used to have a
set of fenders -- mud guards? -- on it. I took them off a couple years
ago, and when doing so I craftily broke off one of the mounting bolts in
the rear dropout. Don't ask. It wasn't one of my prouder moments.

We're getting some rain and it's time to mount the fenders. But I'm
staring at the face of the broken bolt. And it's not wearing a very
helpful expression.

I have a feeling that things are gonna get messy real fast.

So it's broken off flush with the outside of the dropout, and there's
nothing on the wheel side to grab onto. The bolt wasn't any special
hardened type, just the usual cheap and cheerful kind that came with the
fenders.

Most articles on broken bolt extraction are targeted at extracting
larger ones from engine blocks and such. Anyone have any advice on how I
should proceed with his little one?



Center the bolt and drill it out. Increase the diameter of the drill
until the inner diameter of the thread. Most of the remaining bolt
thread will fall out. Tap if necessary.

Good advice. I would add this: if you have access, and can maneuver the
frame into place (big ifs), a drill press can be a tremendous advantage
for nailing these holes. The stability of a press helps so much that it
can help drill some pretty nasty stuff. This may be a good time to buy a
simple mount that will hold your hand drill.

The other nice tool for this job is an automatic punch like this one:

http://www.keenzo.com/showproduct.as...1435190&ref=GB

Your local cheap-and-cheerful tool place (Princess Auto or Canadian Tire
around here; Sears or Harbor Freight in much of the US) probably has
one. The advantage is that you gently push the tool onto the
(irregularly-shaped?) workpiece, and then it trips and punches. It's a
little less fussy and a little more fun than a hammer-and-punch.

Harbor Freight will sell you one for $4:

http://www.harborfreight.com/cpi/cta...Itemnumber=621

I'm sure there are good reasons to prefer the pro versions, but one of
those is usually endurance through repeated use. You probably only need
$4 worth of punch for this job.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."