Why is re-facing necessary?

This is not subjective.

When a Campagnolo go-nogo gauge says the head tube and crown race seat are within spec we do not
mill. That's rare.

When Campagnolo piloted gauges slip into a BB shell with fingers only we do not tap. That's
extremely rare.

Now we only face where a flange will bear on the shell, i.e., one side for a Campagnolo Chorus, both
for an ACH, none for a Phil. We're not about making work.

Almost every frame we buy shows some evidence of machining at end of manufacture. "Close enough"
maybe for factory assembly but it isn't right. Conscientious (anal??) shops follow up with a proper
gauge evaluation and check frame and fork alignment before starting a build. Peter seems to have a
similar experience. Anyone else?

The only frames on which I have never seen even one imperfectly machined surface or thread were
Boston Merlins and Albert Eisentrauts. Oh, and Torelli , though I have sold exactly one. It was
extremely clean all over and machined perfectly. I love Waterford to death but their BB threads are
often tight to my gauges. And they at least make an effort!

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

A Muzi said:

When we start seeing frames which do not require facing we'll stop doing
it.

With the exception of lugged frames, most head tubes and BB shells are machined, I assume parted off
from tubing on a lathe. This may be a faulty assumption, but I would like to know what process is
otherwise employed.

If lathe-cut, the ends, before welding, will be squarer and more parallel than you could ever hope
to make them with a hand cutter-- and I say this as an employed machinist who has to do the
operation both ways from time to time. It seems possible, though not probable, to get enough heat
distortion during welding to pull the tube out of round, but out of square/parallel? I don't see it.

Is this paint overspray you are dealing with, or what? Are you getting frames whose head tubes and
BB shells have been saw cut? I am genuinely curious as to what could be amiss.

I reflect on my days as a low-level shop wrench building bikes out of boxed stock. I very rarely ran
across a headset or BB that betrayed signs of binding due to frame issues, and this was in the days
of cup-n-cone bottom brackets. Most of the few headsets that displayed any binding could be cured by
pressing them more firmly. I should note that the "field grade" bikes I usually assembled were
almost never lugged; most were TIG welded steel.

Chalo Colina

"A Muzi" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

This is not subjective.

<<snip..>>

Quoted message said:

Almost every frame we buy shows some evidence of machining at end of manufacture. "Close enough"
maybe for factory assembly but it isn't right. Conscientious (anal??) shops follow up with a
proper gauge evaluation and check frame and fork alignment before starting a build. Peter seems to
have a similar experience. Anyone else?

<<snip..>>

Quoted message said:

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

Like you guys, I've assembled a fair number (probably 50-60) good quality steel framesets..not
custom frames, but pretty fair quality, high-end, mass production frames. I'd estimate that 50% had
to have facing and thread chasing done to them before assembly. Almost all had to have one or the
other. We checked frame alignment before assembly but not fork. Out of that 50-60 number, probably 3
or 4 were bent enough to notice when riding. I always chalked it up to shipping damage, but you
never know. They could come from the factory that way. I've seen fairly good Italian steel frames
where the factory didn't even bother to face the BB shell after brazing OR painting! Incidentally,
when Cannondale first started building MTB's back in the 80's in alu, in the first year we started
receiving their bikes we were getting bikes with absolutely no visible box damage (ruling out
shipping damage) that ran as crooked as a 3-legged dog. We found out later it was a problem with
their heat-treatment process apparently. You think they'd check the alignment before shipping...but
nope, we sent every one of them back, probably 10 bikes that year.

Cheers,

Scott..

Quoted message said:

A Muzi said:

When we start seeing frames which do not require facing we'll stop doing
it.

Chalo said:

With the exception of lugged frames, most head tubes and BB shells are machined, I assume parted
off from tubing on a lathe. This may be a faulty assumption, but I would like to know what process
is otherwise employed.

If lathe-cut, the ends, before welding, will be squarer and more parallel than you could ever
hope to make them with a hand cutter-- and I say this as an employed machinist who has to do the
operation both ways from time to time. It seems possible, though not probable, to get enough
heat distortion during welding to pull the tube out of round, but out of square/parallel? I
don't see it.

Is this paint overspray you are dealing with, or what? Are you getting frames whose head tubes and
BB shells have been saw cut? I am genuinely curious as to what could be amiss.

I reflect on my days as a low-level shop wrench building bikes out of boxed stock. I very rarely
ran across a headset or BB that betrayed signs of binding due to frame issues, and this was in the
days of cup-n-cone bottom brackets. Most of the few headsets that displayed any binding could be
cured by pressing them more firmly. I should note that the "field grade" bikes I usually assembled
were almost never lugged; most were TIG welded steel.

I cannot evaluate a head tube _face_ without running a cutter across it. My guess is that the piece
was, as you note, cut square before welding. One edge is usually high, front or back not to the
side. We don't mill if the head bore gauges pass easily and appear even at the end.

With the tools I have, I can see that the threads in the BB are in one plane and clean enough to
pass a piloted pair of threaded gauges. If they do not pass, we tap, then reinstall the piloted
gauges. Our facing mill runs in that bore so the edge will be perpendicular. Again, a modern BB
looks well faced before its welded but our mill definitely cuts a high spot first on half the frames
that required thread cleaning. It appears thread problems are more due to warping than to poor
initial threading. There are definitely lousy threads even today, cut with worn tools and not in one
plane. If the threads were OK, we wouldn't mill the face at all(barring gross errors). We have no
way to evaluate just a face exclusive of threading.

Yes there's a whole group of frames that have paint issues. And no, we do not even look at any of
those things on preassembled bikes ($200 to $1200) unless there's a gross (visible) error. On those
we only look when the BB is hard to remove for assembly lubrication.

We haven't yet spoken of seatpost bores. Don't you just hate it when a new seatpost gets galled on a
rough seat tube slit? There's one nice thing to say about carbon frames!

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

A Muzi may have said:

We haven't yet spoken of seatpost bores. Don't you just hate it when a new seatpost gets galled on
a rough seat tube slit? There's one nice thing to say about carbon frames!

Now, *that* is a sore point even for *me*. I have ended up dragging out my old ajustable reamers
(and even the Dremel) to clean up edges and straighten the tops of those tubes more than once. Since
I've dealt almost exclusively with used bikes, it was hard to say if the problem was from the
factory or due to the notorious Captain Overtorque's having been the last one to adjust the QR on
the seat clamp, but the lack of any kind of bevel on those edges is a tooth-grinder. On the other
hand, this is one place where I'll admit that the attention required might induce an extra level of
cost that wouldn't necessarily translate to long-term benefit...and might make the unit just
uncompetitive enough in price to put it at a disadvantage.

--
My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
don't respond to something, it's also possible that I'm busy.

A Muzi may have said:

This is not subjective.

When a Campagnolo go-nogo gauge says the head tube and crown race seat are within spec we do not
mill. That's rare.

When Campagnolo piloted gauges slip into a BB shell with fingers only we do not tap. That's
extremely rare.

Does anyone else make a guage? Is Campy's guage more stringent than others? I ask because many years
ago, I discovered that a plug guage I was using to check engine case main bearing bores was marked
for a range that was not as stringent as it should have been. (Fortunately for me at the time, I'd
been setting my borer for the end that was correct...)

Quoted message said:

Now we only face where a flange will bear on the shell, i.e., one side for a Campagnolo Chorus,
both for an ACH, none for a Phil. We're not about making work.

Prudent.

Quoted message said:

The only frames on which I have never seen even one imperfectly machined surface or thread were
Boston Merlins and Albert Eisentrauts. Oh, and Torelli , though I have sold exactly one. It was
extremely clean all over and machined perfectly. I love Waterford to death but their BB threads are
often tight to my gauges. And they at least make an effort!

Your other comments imply that welding-induced distortion is an apparent cause for some of the
out-of-spec faces; that would make perfect sense to me for aluminum (horror stories about which I
have plenty in performance engine building), but I have to wonder about that much shrinkage or warp
in steel. Perhaps the tubing thickness is being spec'ed thinner than is necessarily prudent, in the
name of weight saving? If so, then it would behoove the frame builders to add a post-welding (or
perhaps post-heat-treat) final machining and verification step. Evidently, that's not being done.

--
My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
don't respond to something, it's also possible that I'm busy.

(Qui si parla Campagnolo) may have said:

Chalo-<< You are talking about paint removal here, not finish machining, right?

Quoted message said:

Quoted message said:

<BR><BR>

Not right, actual facing of the headtube and BB shell..

Chalo<< I mean no offense to you or your mechanics when I say that professional machinists
generally do a better job of cutting metal than professional mechanics do. >><BR><BR>

But 'professional machinists' don't make framesets, welders do.

Yes, that makes too much sense. I've known welders who were conversant in the concept of matching
the technique to the result desired, but you had to be explicit with them about where warpage and
dimensional change had to be kept minimized or they'd gleefully shrink two or three millimeters from
an aluminum part that needed some welding work. With adequate direction, better results were
obtained; left to their own devices, they'd overheat the piece every time.

--
My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
don't respond to something, it's also possible that I'm busy.

Quoted message said:

Then relax you do not have a problem. Most riders would be unsure of the answer.

aw, use guys go on about paralleling the sides but don't tell us-besdies leave it alone witch is
outasight advice given the general run of LBS baboons_ butbutbut if one side of the spindle shows
elliptical movement an if that side has a varying width wear path inside on the cup? is that
refacing time or are the cup threads in crooked in relation to the ther sides cup threads. and are
these things correctable with refaceing or is that necessary unless something beyond these things go
on like what?? a very interesting mental visualization of the parts going outa whack and then coming
back into line with refaceing but is that possible??

Quoted message said:

A Muzi <[email hidden]> wrote:

-snip whining about frame machining quality-

Chalo wrote: -snip incredulity- Chalo Colina

Here's a photo I shot today of a brand new famous brand American handbuilt frame. Note the swarf on
the flutes - and most of it ran out with the coolant.

yellowjersey.orgTAPBB.JPGOpen ↗

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

Jim Rogers said:

Will be installing a new bottom bracket and headset on my old bike. An old repair and maintainance
book I have said that the head tube and bottom bracket shell should be faced first. Checked the
archives of this group and several of the gurus here agreed.

Went to my LBS to inquire how much it would cost, and they acted like I was crazy. They contend
that if it was faced once (either at the factory or during the initial prep) and I wasn't having
any problems, then everything was fine and I should just put the new stuff on.

When I tried to defend the idea of facing before new installation, they asked me "if it was square
at one time and you were not having any problems and you didn't crash or anything, how would it
have changed?" They argue that the head tube and bb shel aren't going to bend or anything (absent a
crash), so just there is virtually never a need to re-face.

Not being an expert, I really couldn't answer their question. So I pose it here-- assuming you have
everything square at some point, what exactly changes over the life of a bb or headset that would
require another facing of the head tube or bb shell? Or have I mis-understood something?

--Jim Rogers

I installed a new headset recently and had similar questions. My final decision was that this bike
had done just fine for about 8 years and if the faces weren't square I didn't really care as I was
happy with the un-square results and would be just as happy with another 8 years from the new
headset. I also didn't use any special headset tools, just some wooden dowels of adequate diameter
to pop the old pieces out with a hammer. Took care to work evenly around to keep from ovalizing the
tubes. The same dowel fit nicely into the cups and the new pieces went in fine. Everything's smooth
as a baby's butt. The new headset was dura-ace threaded, and reported to be resistant to indexing
with proper lubrication.

Quoted message said:

Quoted message said:

Then relax you do not have a problem. Most riders would be unsure of the answer.

g.daniels said:

aw, use guys go on about paralleling the sides but don't tell us-besdies leave it alone witch is
outasight advice given the general run of LBS baboons_ butbutbut if one side of the spindle shows
elliptical movement an if that side has a varying width wear path inside on the cup? is that
refacing time or are the cup threads in crooked in relation to the ther sides cup threads. and are
these things correctable with refaceing or is that necessary unless something beyond these things
go on like what?? a very interesting mental visualization of the parts going outa whack and then
coming back into line with refaceing but is that possible??

I believe you are describing a BB that's set up a touch loose. It's important to set
loose-ball systems with a preload (and plenty of clean lubricant ). The FAQ is quite well
written on that point.

draco.acs.uci.eduindex.htmlOpen ↗

Inablity to screw a cup in with fingers, inability to adjust to a smooth condition with a slight
preload or a noticeable gap on one side of a cup lip or lockring would indicate a machining problem.

Your uneven wear is normally indicative of a loose bearing adjustment.
--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

A Muzi said:

Here's a photo I shot today of a brand new famous brand American handbuilt frame. Note the swarf
on the flutes - and most of it ran out with the coolant.

yellowjersey.orgTAPBB.JPGOpen ↗

Thanks.

Is your impression that this was due to the thread not being true to the shell axis, or rather from
heat distortion pulling the shell out of round?

That is, did the cutter take a bigger bite the deeper it went, or was it cutting at some hours of
the clock but not at others?

Chalo

Chalo said:

A Muzi said:

Here's a photo I shot today of a brand new famous brand American handbuilt frame. Note the swarf
on the flutes - and most of it ran out with the coolant.

yellowjersey.orgTAPBB.JPGOpen ↗

Thanks.

Is your impression that this was due to the thread not being true to the shell axis, or rather
from heat distortion pulling the shell out of round?

That is, did the cutter take a bigger bite the deeper it went, or was it cutting at some hours of
the clock but not at others?

Chalo

Out-of-axis, e.g., more on the top of one side and the bottom of the other. Whether this is heat
distortion or poor initial machining isn't clear but the phenomenon is common - cups will thread in
singly but not simultaneously over a cartridge BB and piloted gauges will not go to full depth.

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

A Muzi said:

Out-of-axis, e.g., more on the top of one side and the bottom of the other. Whether this is heat
distortion or poor initial machining isn't clear but the phenomenon is common - cups will thread
in singly but not simultaneously over a cartridge BB and piloted gauges will not go to full depth.

That sounds like an iffy tapping job to me-- not surprising considering the speed and lack of
attention-- and scruffy taps-- with which Chinese slaves are likely to manufacture such things.

It does seem to bear out my impression that press-fitted BBs are a better and cheaper system as a
rule than threaded ones. I think it's high time that quality frames solved the tubular
spindle/adequate bearings dilemma by returning to the American standard.

Chalo Colina

Not only Chineese, I have Giant OCR with Tiagra BB. Same problem.

"Chalo" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

A Muzi said:

Out-of-axis, e.g., more on the top of one side and the bottom of the other. Whether this is heat
distortion or poor initial machining isn't clear but the phenomenon is common - cups will thread
in singly but not simultaneously over a cartridge BB and piloted gauges will not go to full
depth.

That sounds like an iffy tapping job to me-- not surprising considering the speed and lack of
attention-- and scruffy taps-- with which Chinese slaves are likely to manufacture such things.

It does seem to bear out my impression that press-fitted BBs are a better and cheaper system as a
rule than threaded ones. I think it's high time that quality frames solved the tubular
spindle/adequate bearings dilemma by returning to the American standard.

Chalo Colina

[email hidden] (Chalo) wrote in message
news:<[email hidden]>...

Quoted message said:

A Muzi said:

Out-of-axis, e.g., more on the top of one side and the bottom of the other. Whether this is heat
distortion or poor initial machining isn't clear but the phenomenon is common - cups will thread
in singly but not simultaneously over a cartridge BB and piloted gauges will not go to full
depth.

That sounds like an iffy tapping job to me-- not surprising considering the speed and lack of
attention-- and scruffy taps-- with which Chinese slaves are likely to manufacture such things.

Yes, but Andrew said "famous brand American handbuilt frame." (Cannondale?)

Quoted message said:

It does seem to bear out my impression that press-fitted BBs are a better and cheaper system as a
rule than threaded ones. I think it's high time that quality frames solved the tubular
spindle/adequate bearings dilemma by returning to the American standard.

What are the pros and cons of each? I would think that with the American standard adjusting
the chainline would be difficult if not impossible, but I'm not sure how much of an issue that
is nowadays.

Werehatrack said:

cords as required to fit the sockets. Has this become the de facto method of dealing with the
nonstandard wall socket situation, or do people still use adapters, or has the UK finally
standardised the plugs?

Er, you've misunderstood. Plugs are not standard across _Europe_; the UK wall socket has been
standard for decades now, and you would have to look very hard to find the old round-pin
equipment anywhere.
--
David Damerell <[email hidden]> Kill the tomato!

(Gary Young) said:

[email hidden] (Chalo) wrote:

Quoted message said:

Quoted message said:

That sounds like an iffy tapping job to me-- not surprising considering the speed and lack of
attention-- and scruffy taps-- with which Chinese slaves are likely to manufacture such things.

Yes, but Andrew said "famous brand American handbuilt frame." (Cannondale?)

Just because the frame may be handbuilt in America does not mean that the BB shell wasn't bought
from a cheap overseas supplier. "Cost is king" and all that.

Quoted message said:

Quoted message said:

It does seem to bear out my impression that press-fitted BBs are a better and cheaper system as
a rule than threaded ones. I think it's high time that quality frames solved the tubular
spindle/adequate bearings dilemma by returning to the American standard.

What are the pros and cons of each? I would think that with the American standard adjusting the
chainline would be difficult if not impossible, but I'm not sure how much of an issue that is
nowadays.

High quality BMX cranksets (which include the bottom bracket) offer the easiest chainline
adjustability of all. After the cups, which contain sealed bearing cartridges, are pressed in, the
BB spindle slips freely through both sides. Spacing washers are placed over the spindle in order to
bring each side of the crank to its correct alignment, then the arms are installed on their splines
and bolted down. Road and MTB cranks are insanely cheesy by comparison.

Chalo Colina

[email hidden] (Chalo) wrote in message
news:<[email hidden]>... <snip>

Quoted message said:

High quality BMX cranksets (which include the bottom bracket) offer the easiest chainline
adjustability of all. After the cups, which contain sealed bearing cartridges, are pressed in, the
BB spindle slips freely through both sides. Spacing washers are placed over the spindle in order
to bring each side of the crank to its correct alignment, then the arms are installed on their
splines and bolted down. Road and MTB cranks are insanely cheesy by comparison.

Well, then I have to confess I'm at a loss -- why are bottom brackets threaded?

(Gary Young) said:

[email hidden] (Chalo) wrote:

Quoted message said:

Quoted message said:

High quality BMX cranksets (which include the bottom bracket) offer the easiest chainline
adjustability of all.

...

Quoted message said:

Quoted message said:

Road and MTB cranks are insanely cheesy by comparison.

Well, then I have to confess I'm at a loss -- why are bottom brackets threaded?

Beats me. Oblivious engineering? General indifference? The crushing weight of tradition?

Categorical disadvantages of threaded bottom brackets, as I see them:

- Special tooling required
- Can easily loosen or become desperately stuck
- Subject to cross-threading and other thread damage
- More expensive to manufacture than plain shells
- Separately machined coaxial threads are easily misaligned
- Left hand threads required for reliability

To these add the specific shortcomings of English threaded BBs:

- Spindle too small for safety and/or bearings too small for durability
- Limited chainline adjustment & no independent adjustment L/R

Advantages of a threaded BB shell over American press-fitted BB shell:

- Gets you down to your LBS more often
- Rear freewheel hub can be threaded into it, creating sculptural options
- Confounds annoying "lefty-loosy" mnemonic
- Opportunity to use the word "spanner" aloud

Nobody would think a threaded headset was a good idea. Why then should a BB be threaded?

Chalo Colina