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Old 12-07-07, 01:21 AM
  #22  
Bob Dopolina 
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Originally Posted by ParkingMeter
Just two days ago I punched out the cups of a customer's Chris King headset. A little tight-loose pattern and a trashed lower bearing after a year of use. Guess what, head tube not faced. Probably contributed to that. Being anal-retentive, I machined it for him no charge. On a properly machined head tube I've seen those things go for several years with almost zero maintenance.

Frame prep is sort of a "specialty" service that a lot of shops I've been to (and worked for) don't offer. I've seen plenty of trashed tools too; I think a lot shops simply don't know how to do it or don't know how important it is. It's also easy to screw up your tools or the frame your prepping (use lots of cutting fluid, special fluid for aluminum, keep your taps/dies/reamers/facing mills nice and sharp, don't bang the cutters around or store them in a tool box where they'll bang around against other tools, don't turn your reamers and facers backwards when cutting). I've done some hobby-level machining, so I'm probably a little more knowledgeable about machining than the average mechanic (I am not a machinist however). When I started at the shop I'm currently at, I sent in all the cutting tools to get sharpened. The tool grinder ground off about half the lands of the BB taps to get a good edge again, they probably hadn't ever been sharpened with something like 10+ years of use! Cutting tools are unique among bicycle tools: they're expensive, very fragile and high precision. But many mechanics treat them like cone wrenches and vice grips, and they often get ruined (one shop I worked at had a Campy toolset; about a third of the tools were chipped or broken, nearly made me cry, now those are some expensive tools!).
I think a lot of shops got lazy. when Shimano introduced cartridge BBs you could easily get away without facing. Chasing only became needed if there were damaged threads. basically, an entire generation of wrenches gained their experience at a time when you usually didn't need to chase and face.

Now, with BB designs having changed back to a design which benefits from this machining, most of the mechanics simply don't know how any more.
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