On Mon, 16 Jan 2006 17:44:58 GMT, "Leo Lichtman"
<
[email protected]> wrote:
>
>"Mark Hickey" wrote: (clip) Obviously 90+% of the bolts that are ever
>removed and reinstalled aren't slathered with thread locker, yet they don't
>seem to come loose. (clip)
>^^^^^^^^^^^^^
>90%+ of the bolts are tightened so that the torque produces tension in the
>bolt. This produces locking friction in the threads which usually is enough
>to prevent loosening. In cases like the brake caliper nut, (correct me if
>I'm wrong) the nut is tightened enough to take out excess play, while still
>allowing the arms to move without binding. So there is no tension on the
>threads to produce the locking friction. Hence, the need for a Nylock type
>nut, or Loc-tite or tape.
Many use a capnut.
>The other way to deal with this would be to use a shoulder bolt,
Or a sleeve, or two nuts locked together if there's no shoulder or
sleeve.
>but that [shoulder bolt]
>would be more expensive, would not allow fine tuning the clearance or
>compensation for wear.
Why would that be a problem? I ask because it appears that this is a
common design.
A quick look at the cheap calipers in the junkbox and the in-use
stable reveals that most of the ones here have a shoulder for the
caliper arms. The only exception is a scrapped-out early-70s
department store bike whose brakes are little more than scrap metal in
my opinion. Some older cheap side-pull calipers that I can recall
(like the ones I just cited) were essentially impossible to keep
centered reliably; on those, double-nutted caliper mounting
studs/bolts were often employed (and left loose enough that the whole
assembly could "float" to allow the pads to not make heavy contact),
but this was far from an optimal solution.
--
Typoes are a feature, not a bug.
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