Pedal came off crank arm while riding

"Gordon" wrote in message
om...
A bike store can chase the threads for me, but I would like to know
more about the process how it works? Its hard for me to visualize it
repairing the threads and still being as durable originally. Doesn't
chasing make the pedal hole bigger?

I am purposely not using that crank and pedal to prevent further
damage to the bike and myself. I want to make the best and safest
decision.

Thanks.

You'll need to find someone with experience to make judicious decision.
"Chase" as far as I can tell, implies just 'run a tap through the pedal
eye'. You'd think that the clear English phrase, or even "cut" would be
preferred, rather than the obfuscating "chase". Oh, well.

That process cannot add any material. Missing thread material is the actual
problem and a dangerous one at that.

You mentioned yesterday that your pedal does not fully engage the whole
width of the crank thread anyway. Cutting the occluding swarf out of the
front of the thread will let you start the pedal into the crank but it
won't magically restore missing aluminum. Get an informed and experienced
opinion before standing on that pedal.

I suggested earlier that a new crank is the preferred ( under $20) course. I
still think so , even moreso now that someone has suggested "chase" as
"remedy".

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On Sat, 6 Sep 2003 20:56:14 -0500, A Muzi wrote:
"Chase" as far as I can tell, implies just 'run a tap through the pedal
eye'. You'd think that the clear English phrase, or even "cut" would be
preferred, rather than the obfuscating "chase". Oh, well.

The phrase might make it more obvious; but to
say "cut" would be very confusing. "Cut" is how
you describe the action of using a tap to make
threads in a smooth hole.

That process cannot add any material. Missing thread material is the
actual problem and a dangerous one at that.

Agreed. Chasing the threads can remove garbage
from inside the threads, and straighten bent
threads (which will then be weakened, most
likely; see other messages here regarding
metal fatigue...).

I suggested earlier that a new crank is the preferred ( under $20)

At $20, I'd not bother fooling around with
anything else.

--
Rick Onanian

On Sat, 6 Sep 2003 20:56:14 -0500, "A Muzi"
wrote:

You'd think that the clear English phrase, or even "cut" would be
preferred, rather than the obfuscating "chase".

back in the "old" days .. lathes had a special geared shaft that was
used to "chase"/create threaded parts.... that term has just carried
thru to modern times.

charlie

"Rick Onanian" wrote in message
news
On Sat, 6 Sep 2003 20:56:14 -0500, A Muzi wrote:
"Chase" as far as I can tell, implies just 'run a tap through the pedal
eye'. You'd think that the clear English phrase, or even "cut" would be
preferred, rather than the obfuscating "chase". Oh, well.

(ro) The phrase might make it more obvious; but to
say "cut" would be very confusing. "Cut" is how
you describe the action of using a tap to make
threads in a smooth hole.

(am) That process cannot add any material. Missing thread material is
the
actual problem and a dangerous one at that.

(ro) Agreed. Chasing the threads can remove garbage
from inside the threads, and straighten bent
threads (which will then be weakened, most
likely; see other messages here regarding
metal fatigue...).

(am) I suggested earlier that a new crank is the preferred ( under $20)

(ro) At $20, I'd not bother fooling around with
anything else.


Straighten bent threads?????

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On Tue, 9 Sep 2003 02:12:57 -0500, A Muzi wrote:
(ro) Agreed. Chasing the threads can remove garbage
from inside the threads, and straighten bent
threads (which will then be weakened, most
likely; see other messages here regarding
metal fatigue...).

Straighten bent threads?????

Yes, when a pedal is not threaded in fully and
pulls out of the crankarm, not only will it strip
it's own threads, but I'll bet the threads in the
crankarm will be deformed and/or stripped.

Running a tap through those deformed threads may
push them back into the proper shape. Threading a
pedal in from the other side might do that better,
if it has good quality threads.

Mostly, I suppose, the tap is more likely to cut
the offending shape off than push it back into
place.

Of course, if the threads are actually stripped,
then no tap or bolt will bring them back.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
--
Rick Onanian

"Rick Onanian" wrote in message
news
(ro) Agreed. Chasing the threads can remove garbage
from inside the threads, and straighten bent
threads (which will then be weakened, most
likely; see other messages here regarding
metal fatigue...).

On Tue, 9 Sep 2003 02:12:57 -0500, A Muzi wrote:
Straighten bent threads?????

(Mr Onanian continued) Yes, when a pedal is not threaded in fully and
pulls out of the crankarm, not only will it strip
it's own threads, but I'll bet the threads in the
crankarm will be deformed and/or stripped.

Running a tap through those deformed threads may
push them back into the proper shape. Threading a
pedal in from the other side might do that better,
if it has good quality threads.

Mostly, I suppose, the tap is more likely to cut
the offending shape off than push it back into
place.

Of course, if the threads are actually stripped,
then no tap or bolt will bring them back.



I think you do not use taps and dies in aluminum.very often .
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On Tue, 9 Sep 2003 22:00:30 -0500, A Muzi wrote:
I think you do not use taps and dies in aluminum.very often .

I stand corrected. I was thinking of how
they've worked on steel for me, in
non-cycling applications.

Aluminum threads would break before they
would bend back. However, if the crank
isn't aluminum, it might work; then again,
if the crank isn't aluminum, it's probably
cheap enough to replace for all that effort.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
--
Rick Onanian