lapping a hub?

this may be a dumb question, but why do you lap the hub and axle...

 

So it is a nice fit after you clean off the leftover compound. You want the mating tapers to seat and carry the load and not depend on the key holding things in place.

 

I didn't know that your did? I ***ume we're talking about tapered axles and hubs? If thats the case, I'd think it would make for a better match and even tighter fit.

 

It's no different than when you lap a gear when you put it on a shaft.