|Tapping and Facing frame worthwhile?||dirtpoor|
Feb 3, 2003 3:11 PM
|I'm building a Schwinn Fastback with a Dura_Ace group. Older bike maintenence books suggest tapping and facing the BB shell. Is it still recommended with new frames?|
|mabye I'm a dolt, but I don't||DougSloan|
Feb 3, 2003 3:45 PM
|I've built up 7 or 8 of my own bikes, and never did it, with no problems. As between tapping and facing yourself (if inexperienced) or building without, I think you should forego it. You could do much more harm than good.
|I think so.||RJF|
Feb 3, 2003 4:27 PM
|I just bought a new frame (a Pinarello) and on the distributor's recommendation had the headtube and BB faced, and the BB tapped/chased/whatever.
Can you live without it? Probably. But having it done will make building your bike easier, and it will ensure that your headset and BB are working fine, and probably wear better.
I figured that since I spent all that money on a frame, why not spend the extra $35 to do it right?
|Depends on the frame||Kerry|
Feb 3, 2003 4:37 PM
|The need for tapping threads can be determined pretty much "by inspection." If there is no paint in the threads and they are clean (free of burrs) then there's no need to tap them. Tapping threads came from the days when frames were tapped, then painted, then shipped. They often arrived with BB, derailleur hanger, shifter bosses, and bottle bolt holes full of paint, in some cases making it very hard to start a thread without tapping first.
Facing is another question. Any frame can be off on the BB and head tube faces, even if it was done at the factory - it's something that should not be screwed up but seems to happen too often (5% of bikes? no data - just guessing by hearing of problems). The head tube and BB can appear to have been faced (bare metal) but not be parallel. Depending on the frame supplier and my access to facing tools, I would at least try to find out if the faces are parallel. Use a couple of long straight edges to see if the job was done right.
|re: Tapping and Facing frame worthwhile?||laffeaux|
Feb 3, 2003 5:51 PM
|If it was not done at the factory or by the retailer where you bought it, I'd say do it. A good LBS will do it cheaply. I chased BB shell will allow you to install the BB without tools (up until you need to torque it down).
You should be able to look at the edge of BB shell and head tube to see if they have been faced. Your BB and headset may not seat properly if the tubes were not properly faced.
If it's a frame you've spent a lot of money on, why not spend the extra $20 to make it perfect?
|re: Tapping and Facing frame worthwhile?||Calvin|
Feb 4, 2003 6:26 AM
|As a rule, if the bike goes together well, and adjusts well, this machining was not necessary. In other words, frame machining can be applied to solve problems. If the bottom bracket installs well and adjusts without a tight-loose pattern, then all was well. If not, machining is needed. The same is true of the headset. |
For bb tapping see http://www.parktool.com/repair_help/howfix_bbtap.shtml
In the image below, the shell face is completely faced. Notice the arrow. This is a low point, but there is still a fresh face cut completely around the circumference.