Mark, et al:
> Not sure what you mean by "properly relieved", could you elaborate?
You're right, Mark, that's a poor term. What I should have said was
"prepared" and by that I mean the inside of the tube should probably have a
"clean up ream" and then honed with a "bottle brush" or brake cylinder type
hone. The reamer, to remove burrs, stray paint and primer, and other
imperfections inside the tube and at the top of the seat lug. The hone, to
polish.
> A flex hone is a cool tool, I've flex-honed hundreds of frames (maybe a
> thou?) but as far as I know it's impossible to do on a painted frame
without
> wrecking the paint, at least a little, right at the opening - do you know
a
> technique for preventing that?
I use the flex hone only inside the tube and don't insert or remove while it
is spinning. The brake cylinder hone is the ticket for polishing the very
top. Since the stones don't splay all over the place when you remove it,
you can decrease the rpm of the hone while still partially inserted to
polish the very top of the seat lug opening, then stop it completely and
remove it. It does no damage to the paint unless you are careless.
> He said 27.0 fits now; did you mean the flex-hone might make a larger post
> fit? In my experience, a flex hone won't take any appreciable metal off,
it
> just smoothes the finish. I don't think I've ever seen it allow the next
> larger size post to fit.
I agree.
> I've also rigid-honed maybe a hundred frames... It's wonderful for 853 or
AerMet 100
> Alloy, where the metal is too hard for a reamer.
Does a reamer work without chattering on 753 which is also hardened?
> I'm not sure, were you saying that if he has a nice 27.2 post he wants to
> use, it's still a bad idea to ream?
If the wall thickness will allow it, I think it's ok.
> Is that based on having tried it and
> having had bad results?
It is based on 2 things. First, I have had frames in which the seat posts
fit so tightly they had to be forced into and out of the seat tube and I was
sure the seat post was too big. Eventually, I got the bright idea to look
inside the tube and saw all the metal shavings, ridges on the slot, paint,
grease, etc. Thirty minutes later, after some solvent, a file, and a flex
hone, the seatpost magically fit. Could that be the case, here? Does a
27.2 not fit at all? The second experience was last weekend when I enlarged
a steerer tube with an adjustable reamer. I didn't botch the job, but it
would be very easy to do. This is a serious tool and its use with a thin,
hardened tube like 753 gives me the willies. Maybe that's from my lack of
experience.
> I claim, based on having done it numerous (maybe
> dozens?) of times, that it can work out just fine, especially on a frame
> that SHOULD (my caps-RC) have had a 27.2 post to begin with... Note, we
still don't know for sure what size seat tube Jack has; if it's
> metric (28.0mm outside diameter) then 26.6 is normal, 26.8 is OK, and 27.0
> is pushing the limits, so he better not try it.
I agree.
Rick Chasteen, Kansas City