Stuck crank removal?

FastBass

Hi everyone,

I ride a modified hybrid (equipped with triathlon bars) which is a good
bike despite being inexpensive, but I'm constantly having problems when
trying to replace the crankset. All the bottom brackets (some old-fashioned,
adjustable, with separate ball bearings, some cartridge-type, sealed) are
of the same square taper profile. It's more of a removal problem, any time
I try to use my crank removal tool, the inner threads (where the dust caps
usually are) of cranks get stripped right away, but the cranks won't go off.
I imagine that may be because I use a hammer to drive a crank on a spindle,
since if I don't do it, it starts to fall off during a ride, usually far
from home, which is very embarassing. So what's wrong in my approach?
How should I install/replace the crankset properly?
I consider replacing the existing 28/38/48 set (it's riveted, no replaceable
chainrings) with a bigger road triple in time, but I don't want to wreck it,
since it is a bit more co$tly.

What do you say?

Thanks a lot in advance,

Serge in Odessa, Ukraine