the tell all NO HOLDS BARRED alignment thread atmo -

[e-RICHIE]

i once had a decent and fairly long email exchange with dazza on this and here is my short answer based on that experience -
if i start with a rectified shell, make a frame (or main triangle...), and am pleased with the results (read: it passes my smell test), that's that.

when i add the rear assembly, clean it all up, chase threads, replace it on a table - and then see that all of the sudden (as an example) the seat tube is now leaning to/from the table a C hair more than before, i do in fact measure the shell and notice a slight change (shrinkage, warp, whatever...) but rather than use a facing tool i take some A/O cloth on the flat side of an 8" half-round file, and i finesse the one area of the shell face that needs a shave. it's usually 2-3 soft strokes and the frame, back on the whipping post, again shows the same reading that it did when it was a main triangle without more parts added. i view it as the frame staying the same but the reading surface varying from time to time, and my fix is planing one part of it by hand rather than using a cutting tool.

Cool.

My experience with shells is that they are faced very well from the casting house and are fine without facing to start but it's after they have been heated asymmetrically (all the tubes being on one side) that the top side shrinks and the faces go wonky.

Have you measured the width/parallelness of the shell after brazing? I would expect that you would find that the top side (where most of the heat is) would get narrow. I usually see the top being about .005" narrower that the bottom and when projecting this angle over the length of the seat tube you end up with the top of the seat tube being low which would result in the top of the seat tube being about 2 mm low on the plate. This is one reason I face post brazing. The other is that I want the faces that the BB bearings snug up to to be parallel so that the bearings will have the easiest life possible.


dave

[liberacefanboy]

What a great topic for a thread, and builders are right on here: its a Taboo subject.
i have always told clients, customers what I allow for "tolerances",
and having built up( assembled with parts) thousands, and I do mean thousands of bicycles, I have faced, chased and aligned more bikes than a lot of people. I used to work for a big ole parts wholesaler and I worked in the "bike builder" department, and I saw many different brands come in to be built. From full on carbon customs to the real deal steel, and everything in between, including many handmade builders, even some of the guys on here. So, with that being said ( typed) I have seen what some companies and builders have as a "tolerance". The general conclusion was that 98 % of the custom builders were dead on,l and aa few were horrible. The mass produced carbon bike were hit or miss, and the most consistent ? Stuff coming out of maxway ... but I digress...
I have learned this:
Do tube runout, and check actual butting ... and make sure the bb is faced from the start. If you start square, you have a better chance of ending square.
If you know and understand how heat distortion works, use that to your advantage. Adjust for it. I learned this when I was welding for a little custom car fab shop.
What really matters is if the head tube, seat tube/ bb, and dropouts are all in the same "plane". That is the real deal.
I agree with the guys when they say a mm is all good, and if you are getting it down to .001, then you are really just chasing the dragon ...
And, when it is all said and done, how round are your tires? Is your wheel dished perfectly? Do your tires wera evenly? How straight is that carbon fork?
Is your stem twisted? ( I just had this issue, and it was way messed up)
It is important that we as builders get it as straight as possible, hope hope that the rest just lines up.
noren

[John Winston]

the plate isn't riding the bike.

hey, that was a joke.

No worries here, my plate though....not much of a sense of humor, and a big fella at that. Fortunately, he's painfully predictable-

[steve garro]

You build to the highest allowence your materials allow.
That's all I have to add to all the excellent advice above.
I check the ST/BB as a sub-assembly, then the front triangle before it's connected to the CS's as not to carry on any front triangle twist to the stays - while it's a triangle you can use tacks to do any pulling you need on a triangle.
Then I put on the CS's & check the wheel alignment, then put on the SS's & check again.........then put on the SS brace & check, then braze & one last check.
It's all good then. - Garro.

[Craig Ryan]

This is an informative thread. It's answered some questions and verified some beliefs.
What I've noticed:
- Until you can measure, you really don't know. So get good stuff to measure with.
- Just because you can measure doesn't mean you can build straight.
- Maybe I've been a bit hard on myself. ;-)

[Dazza]

Dazza, I'm curious what measurements in particular you think need to be within 0.1-0.2 mm (0.004-0.008"). Do they "need" to be there for the sake of the rider or for the sake of your piece of mind?

I've always tried to adhere to Richard's rule of thumb that all error should sum up to less than 1 mm, and the reason is it was the only rule of thumb I could ever find or get anyone to admit to. There have been other statements in this thread that really echo my own thoughts. I think most builders chase alignment because we can and we think we should because its our name or company on the downtube. But Richard's post above about the economics of chasing perfect alignment really makes me think about the countless frames that have been made over decades by workers getting paid per piece and they were cranking them out and the vast majority rode just fine. I'm certainly not going to change my practices in the reverse direction of where I'm trying to go, but it's certainly great food for thought.

.2mm vertical on the rear dropout will be .49mm at the rim radius of 311mm
In my world it is normal to fiddle dropout vertical a few tenths of a millimeter with a file to get this on my inspection plate
and double checking with a wheel
and as Dave mentions, seat stay bows etc all have to be sorted, aligned to the be centered in the stays could be false so in the forming up stage I sort and align the stays before brazing
and again the inspection table is the tool, rolling the stays and tubes.
I am not sure where 1.00 mm is referring to?
1mm over 300 HT to ST twist for me is a failure.
I work to .3mm max tolerance over 300mm of HT. I never use tube surfaces for references, I use tube ends. Cones/rod only in tube ends that have been squared/faced off in the beautiful thing (lathe) thus the cones are correct referencing.
I can get .3mm in 19 of 20 frames on my inspection plate with no cold setting and this is post reaming facing with out cold setting.
To get good cutter path entry into the head tube it is important to have a very square end to the HT, I machine all my HT lug faces on the lathe and when I trim the HT with saw after brazing I can file the last bit flush with the head lug knowing it is a good surface and then deburr carefully and use the cutter/mill/facing tools.
I also braze my bottom head lug first and trim and mill/face and I can correct the hockey stick in the frame triangle as the rest is just tacked
before doing the other brazing.
BB distortion when brazing is some thing Dave mentions in his post and this is important
as .05mm at the BB face will give a tube run out of 1.5mm at the end of a 570mm long tube
I think many have been heaving and tugging at frames with never allowing for BB distortion or trying to understand it
I am very rushed here and due to some dead lines to meet and and have been working over the weekends so I have been unable to add much to this subject
but it is very cool that some builders here have been very good with this subject
very unlike other builders I have met over the years since 1979
and this is super
very super

oh one thing that makes me sigh over the years
is granite tables with digital height gauges which are all cool
but when the builder claims they build to 0.01mm just because their measuring tools can measure that
well, this is just nonsense. Marketing bull.
I read hear, things like I check alignments and then when all is perfect I do this
well what does that mean?
what tolerance if they even understand it?
I have got to go
so much to do today
but I am motivated when time permits later this year
to make a document with a drawings with what I found are my tolerances and reference points
that I have found practical every day.
We make frames better than they need to be
but hey, this is pleasing
and clients appreciate it
I am not saying my way is the best or correct way, I just want to put it all down for discussion and sharing
and reading what others do is a good thing for all

[Dazza]

This is an informative thread. It's answered some questions and verified some beliefs.
What I've noticed:
- Until you can measure, you really don't know. So get good stuff to measure with.
- Just because you can measure doesn't mean you can build straight.
- Maybe I've been a bit hard on myself. ;-)

Bingo

[Dazza]

i once had a decent and fairly long email exchange with dazza on this and here is my short answer based on that experience -
if i start with a rectified shell, make a frame (or main triangle...), and am pleased with the results (read: it passes my smell test), that's that.

when i add the rear assembly, clean it all up, chase threads, replace it on a table - and then see that all of the sudden (as an example) the seat tube is now leaning to/from the table a C hair more than before, i do in fact measure the shell and notice a slight change (shrinkage, warp, whatever...) but rather than use a facing tool i take some A/O cloth on the flat side of an 8" half-round file, and i finesse the one area of the shell face that needs a shave. it's usually 2-3 soft strokes and the frame, back on the whipping post, again shows the same reading that it did when it was a main triangle without more parts added. i view it as the frame staying the same but the reading surface varying from time to time, and my fix is planing one part of it by hand rather than using a cutting tool.

I would have that email here some where

[zank]

.2mm vertical on the rear dropout will be .49mm at the rim radius of 311mm
In my world it is normal to fiddle dropout vertical a few tenths of a millimeter with a file to get this on my inspection plate
and double checking with a wheel
and as Dave mentions, seat stay bows etc all have to be sorted, aligned to the be centered in the stays could be false so in the forming up stage I sort and align the stays before brazing
and again the inspection table is the tool, rolling the stays and tubes.
I am not sure where 1.00 mm is referring to?
1mm over 300 HT to ST twist for me is a failure.
I work to .3mm max tolerance over 300mm of HT. I never use tube surfaces for references, I use tube ends. Cones/rod only in tube ends that have been squared/faced off in the beautiful thing (lathe) thus the cones are correct referencing.
I can get .3mm in 19 of 20 frames on my inspection plate with no cold setting and this is post reaming facing with out cold setting.
To get good cutter path entry into the head tube it is important to have a very square end to the HT, I machine all my HT lug faces on the lathe and when I trim the HT with saw after brazing I can file the last bit flush with the head lug knowing it is a good surface and then deburr carefully and use the cutter/mill/facing tools.
I also braze my bottom head lug first and trim and mill/face and I can correct the hockey stick in the frame triangle as the rest is just tacked
before doing the other brazing.
BB distortion when brazing is some thing Dave mentions in his post and this is important
as .05mm at the BB face will give a tube run out of 1.5mm at the end of a 570mm long tube
I think many have been heaving and tugging at frames with never allowing for BB distortion or trying to understand it
I am very rushed here and due to some dead lines to meet and and have been working over the weekends so I have been unable to add much to this subject
but it is very cool that some builders here have been very good with this subject
very unlike other builders I have met over the years since 1979
and this is super
very super

oh one thing that makes me sigh over the years
is granite tables with digital height gauges which are all cool
but when the builder claims they build to 0.01mm just because their measuring tools can measure that
well, this is just nonsense. Marketing bull.
I read hear, things like I check alignments and then when all is perfect I do this
well what does that mean?
what tolerance if they even understand it?
I have got to go
so much to do today
but I am motivated when time permits later this year
to make a document with a drawings with what I found are my tolerances and reference points
that I have found practical every day.
We make frames better than they need to be
but hey, this is pleasing
and clients appreciate it
I am not saying my way is the best or correct way, I just want to put it all down for discussion and sharing
and reading what others do is a good thing for all

The 1 mm was a reference to Richard's post (post #3 in this thread).

[Dazza]

Yeah, I agree. It's tough to distill a whole process into a single summary post. I'm certain that we are all doing things at every point in the process to control alignment. I find in my own process that the more attention I pay to making sure my miters are as parallel or perpendicular as possible (depending on the tube/tube interaction of course), the better it looks on the plate after tacking and the less it moves during brazing.

One thing that has always baked my noodle is the 0.002-0.005" clearances in a socket that are suggested for brazing. Let's say you have 0.003" clearance in a BB socket for the down tube and you tack the tube on the side of the socket rather than in plane with the center of the frame. Say the tack cools and the tube pivots to closes the gap to 0.001. The deflection you would measure at the other end of the tube is 0.048". To most of us, that's a mile. It puts into perspective the tolerances we are really working with at the actual joint.

yes
yes yes
and the tube braze clearance is nonsense many times
after one changes lug angles
and the distortion in the casting
it is common to have .50mm gaps inside lugs
maybe not at the shore lines but inside and thus when I braze I pay attention filling the lug as well
as you know MAX lugs are totally dreadful with gaps and clearances
brazing them is like filling concrete form work
one fills the lug with a cold shore line at one end of the lug
we have to do our best with the materials on hand

[e-RICHIE]

having spent 3 hours at the car dealership's waiting room and am at wit's end i will add another opinion atmo -

i would rather - much rather - make a frame that, after brazing, expanding, contracting, and then trying to talk back to me - i would rather concede to my personal tolerance borderlines (see posts above) than to cold set it into closer tolerances by means of leverage. iow, my atmoville community standards for what's better include letting what is just be rather than trying to , er - improve it with brute force. i am into the organic nature of assembling these frames. the material tells you what it wants to be, but you tame it as best you can, and then live happily with the consequences.

what masters do others here serve?

[zank]

I agree. I know that nobody will agree with me on this, but I think that once the frame is out on the open road and the rider does that first town line sprint or jams up that first hill in the big ring that the frame is going to settle back closer to where it was in its post-braze/weld state.

[steve garro]

Just for shits & giggles - check a frame, set it in the sun with one side out until warm & then quickly bolt it down & check it out - fun! - Garro.

[edoz]

Just for shits & giggles - check a frame, set it in the sun with one side out until warm & then quickly bolt it down & check it out - fun! - Garro.

DWF made mention of that in his NAHBS seminar. When I got home I clamped a tube in my vise and set up a dial indicator against it. I went to town getting it to move around with various heat sources.

[steve garro]

DWF made mention of that in his NAHBS seminar. When I got home I clamped a tube in my vise and set up a dial indicator against it. I went to town getting it to move around with various heat sources.

Damn. Now I gotta try that. Maybe with a BB/ST sub assembly. - Garro.

[EnginCycles]

i would rather - much rather - make a frame that, after brazing, expanding, contracting, and then trying to talk back to me - i would rather concede to my personal tolerance borderlines (see posts above) than to cold set it into closer tolerances by means of leverage. iow, my atmoville community standards for what's better include letting what is just be rather than trying to , er - improve it with brute force. i am into the organic nature of assembling these frames. the material tells you what it wants to be, but you tame it as best you can, and then live happily with the consequences.

what masters do others here serve?

I agree with this as well. I feel a bike once connected at all the dots is what it is and wants to be there. What it takes to move it is daunting and I feel can not be better than just leaving it and knowing no human can tell a difference. It obviously needs to be within my wanted tolerance but that can be known once tacked. Once welded all bets are off and it is what it is (at least from a front end standpoint). Shifting the rear stays a bit is something I do except for ultra thin heat treated stays. They are left alone.

-Drew

[Dazza]

DWF made mention of that in his NAHBS seminar. When I got home I clamped a tube in my vise and set up a dial indicator against it. I went to town getting it to move around with various heat sources.

the tubes are cold drawn
this puts in built stresses in them
the shaped tubes are even worse
as some of material is in a state of stress
and some the material is against this
and heat can relieve some of this
also there is distortion due to expansion when some of the material is plastic etc

it is like getting a piece of cold rolled bright steel bar and machine/mill a slot and watch it curl up
as the material is not stress relieved, the skin is in a state of stress so when you remove some of it you get distortion from the other areas of material under stress and thus strains
tubing is the same
this is why I hate shaped main tubes!
so the skill of what we do is to work with the materials
with what is practical
while aiming for a good result
what this thread can be is
assisting each other to aim better

[e-RICHIE]

there are alotta cats reading who haven't barged in yet -
i foresee some new posts added before long atmo.

c'mon - help write the book...

[e-RICHIE]

to cliff's notes me up atmo...

frame, on table, drive side up -
1) seat tube centerline height over its length using the pipe O.D.
2) head tube centerline (not surface) over a meter's length using an M+L rod for the virtual center.
3) head tube centerline mimics seat tube's (iow the 28.6mm marks on the M+L rod are in the same plane as the seat tube).
4) top tube and down tube aren't looked at all period.
5) rear dropouts are 131mm and equidistant from the front triangle's centerline.

frame, held by shell in vice -
6) distance between dedicated shop wheel (rim) and seat stays is beyond visibly symmetrical.

for numbers 1-5, the tolerance is one point can be off up to a mm OR all measured points can sum up to a mm.
for number 6, if one seat stay is longer than the other, i file up the dropout slot to bring the wheel in center.

[Craig Ryan]

I check my frames rear end on the table with a wheel as Dave pointed out, but I also verify my seatstay length with my frame in the vise with the rear wheel in. I place a straight edge across the head tube and seat tube even with where it lines up with the top of the rear wheel. with the materials I use and wheel I build with, I get 4mm to the straight edge from each side of the rim at the wheel's top. I find it hard to measure the space between the rim and stay accurately, so I also have a Spudnik wheel checker.