Tom Sherman wrote:

smack. Brinelled bearings. specifically unjoyous deployment
of a 4lb hammer when the car's own function can serve the
purpose, and not damage anything.

How come bottom bracket bearing do NOT have this problem when a
hammer is used to drive cotter pins in [1] and out on cranks?

[1] No, tightening is NOT done with the nut with attaching a
cottered crank.

When cotter pins have to be pounded in, there's something
horribly wrong. It usually happens from the bike shop who
doesn't quite have the exact match of what you require, and
gives you what they consider the next closest thing. It's an
all too common occurrence.

Anyway, bearings get ruined by being used dry of lubricant.

I'd like to hear more about that. Who rides with lubricant free
BB bearings?

A number of Pacific Northwesters who frequently ride through deep
puddles and torrential rainfalls, and don't maintain their bikes
as well as they should for the prevailing conditions.

Besides, no matter how you brace the spindle when pounding in
cotters, the shock reaches the ball or two under the spindle. In
addition, I saw many cranks secured without more than a 1/2 lb
hammer held under the crank, yet no dents in the spindle
resulted.

I still have cottered crank spindles lying around that have no
sign of Brinelling although I have a few head sets where both top
and bottom ball bearings as well a roller bearing ones have
fretting dimples.

You shouldn't have to pound them in. If you have to pound them
in, they don't fit. Maybe tap them in a little, sure -- but to
~pound~ them in?! Nay.

I see you don't work with these. They must be pressed in with
enormous force to give enough preload and insure no "lift-off" from
the small cotter face under hard torque. Those of us who lived
through the steel crank + cotters can recall how they failed with
excess torque if not installed forcefully enough.

They must be driven in with a hammer or a special press. Not only
that, the also needed to be filed to the right wedge angle to match
the other crank in a one side replacement. The off-the-shelf
cotter not being ready to install. The flat taper was only an
indication of where the flat belonged because the threaded end was
offset to pass under the spindle flat. Again, it is a retention
nut, not one that can be used to install the cotter, it having
insufficient strength for that task.[...]

See http://www.sheldonbrown.com/var/images/var0012.jpg.

Nice item. As you can see, those were the "good old days" of bicycle
mechanics. Fortunately Sheldon saved evidence of that.

Jobst Brandt