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prepare frame question(7 posts)

prepare frame questionQubeley
Dec 8, 2002 3:14 PM
I just ordered a frame from LBS.
Can someone tell me what does preparing frame include and the purpose of it?
Frame prep varies, but here's a listKerry
Dec 8, 2002 4:07 PM
- chase threads on BB to remove shavings & paint
- face BB to make sure both sides are absolutely parallel
- face head tube to make sure to and bottom are absolutely parallel
- ream seat tube to insure proper size, removal of burrs, and removal of paint
- chase derailleur hanger threads
- chase dropout threads
- chase brake bridge and fork to insure brake bolt fits
- check rear dropouts and derailleur hanger to insure alignment
- chase fork steerer tube threads (if threaded)
- chase fork crown race seat to insure proper diameter for headset crown race

Few shops will do all of this, but a truly well-prepared frame will have it all done. I think the purpose of all of these items should be self-explanatory
Kerry is right on, as alwaysgtx
Dec 8, 2002 4:54 PM
this site should have you write up a FAQ
chasing = thread cuttingthe other Tim
Dec 8, 2002 7:33 PM
Not something you would want to do to brake mounting holes or a fork crown.
I think tapping = thread cutting.up_hiller
Dec 9, 2002 6:51 AM
Isn't chasing a different process?
yes ...the other Tim
Dec 9, 2002 10:16 AM
and no. Tapping is the process of cutting internal threads, usually with a tap. External threads can be cut with a die. Internal and external threads can also be cut (or rolled) on a lathe using a single or multi- pointed cutting tool. Taps and dies can also be used on lathes and milling machines.

Thread chasing is the process of cutting threads, internal or external. The term is often used (by mechanics, more than machinists) to describe cleaning up threads that have been damaged, or to remove burrs from freshly cut threads. Consequently, people think 'chase' means to follow, as in following the existing threads. Actually, it comes from a difference meaning of the word: chase = a groove or channel. Others incorrectly think it refers to cutting threads on a lathe, where the carriage follows or chases the lead-screw.

In any case, chasing is cutting threads (or grooves), and is not something you want to do to a fork crown or brake mounting holes.
reamingis what he meant.....MrCrud
Dec 9, 2002 10:22 AM
Chasing threads means cleaning them with the propper tap. Your not really cutting new thread, just removing anything debris that's stuck there.

Tapping is creating new thread altogether.

Reaming is adjusting the size of a hole the the right spec. Such as reaming a seat tube, brake bridge holes.....

Cheers!

Mr.Crud