Bicycle Mechanics - Refacing frame surface for headset/BB installation

Another question while I'm waiting for the frame saver to dry.

How important/nessesary is it to reface the BB and headset surfaces when installing new parts? The surfaces seem true (i.e. smooth) but I can't be sure the are exactly parallel. The frame in question is high end steel and a quality threadless headset (Cane Creek) and square taper BB (XTR UN-91) is whats being installed.

Also is it worth paying to have the threads chased in the BB? They seem in good shape and old BB came out no problem.

If the threads are in reasonably good shape there's no real reason to have them chased, just make sure they're cleaned and regreased when you install the new BB. The question of facing is an easy one if the frame has never been prepped...yes, absolutely. The more prep you do yourself (removing old parts, cleaning out old grease and gunk), the less the shop is going to think of giving you a good deal and doing the work right on the spot.

On frames that have already been prepped properly the first time, I would just inspect for visible burring or scoring or wear and proceed as necessary (easier done on thick aluminum than skinny steel). Since steel is easy stuff to cut and a light run over it with the tool just to remove wear and ensure parallel surfaces won't *hurt* anything, go ahead and do it if it'll make you sleep better at night. Your frame and headset and peace of mind are probably worth the meager amount they'll charge if the frame is clean and ready to go before you even hand it to them.

The question of facing is an easy one if the frame has never been prepped...yes, absolutely.

This is just more of that voodoo stuff the ARs insist has to be. My strong foco and merlin Ti frames came faced.None of my dozens of others were.No issues to date. I actually had a frame ruined by a shop monkey,cuz early on I bought into that voodo,but no more.

Thanks for responses and advice. Frame had never been faced (had original painted surfaces) and LBS had free time this afternoon. Was a good decision as both headset and BB surfaces were far out of true and I'm sure both new headset and BB will be much happier.