Metacortex

We don't know which datum they used, which is why it would be great to hear from Waterford. If I were designing a frame I would want to base the main triangle off of a directly connected (i.e. welded or brazed) part, meaning either the top tube, seat tube or head tube.

repechage

Not worth it.

How many frames have your built?

Metacortex

Not worth knowing which datum they used? Then why all the fuss?

"My" have built exactly zero frames but I do know how to measure angles and read an engineering drawing. Until or unless Waterford weighs in there isn't much more to say about that specific model...

repechage

I would not waste Waterford, or Dave Wages' time.

I think Scooper has built a frame or two, I have also. Go build a few and that perspective will change your mind where we have not been able.

Metacortex

How would my perspective change if I built a frame? I'm honestly curious about why and where the discrepancy between design and execution happened. Wouldn't you want to know the same?

OldsCOOL

Here is the bike that inspired my original question....

'77 Super...

Blue Belly

This type of thing is always interesting to know. I agree with you.

The "1" frame I built was designed off of my Pinarello Montello. The only changes I made were to lengthen the top tube by 1cm(fit reasons). The result, geometrically, was perfection for me. I don't understand why there are so many uptight people on this forum but, building is an experience that does alter your perception. But that is mostly a perception of what it takes, skills & alterations you might make to adjust frame feel due to tubing variances. Geometry is geometry, once you have your preference sorted out.

Sir_Name 

I don't see this conversation as being too uptight. My take, with zero frames under my belt but a fair amount of mech. engineering experience (even some that's pertinent to this discussion ), would be to set what matters as the datum. The axle centers matter in real world use far more than how level the top tube is. Accept that the metal will not match the drawing 100% and allow the fudge factor to stack up where it doesn't affect the handling or location of anything critical. Axle centers directly affect the contact patches.

jimmuller 

I'm with S_N. This doesn't feel like up-tightness (up-tightitude?). Maybe we should jump over to the 49.

I find this interesting. I have never built a frame, but I can also claim never to have destroyed one either.

Blue Belly

It is the short answers telling the questing party to essentially "move on". He has a good question.
in this day & age, variances should be thought of as poor
manufacturing. With everything being so precise, there's no reason for it. Everything built off of the axles, the only question one should have is the stack height of the bottom assemble of the headset. Top tubes aren't too critical(agreed) but, anything can be mitered to fit precisely where & how it should. Hell, I built my jig from parts you can get at your local hardware store & My measurements turned out pretty damn close.

repechage

Pretty darn close is not good enough for Metacortex.

Tubes and lugs, even investment cast lugs and modern tubes are not that precise.
Buy a tube set and roll them on a surface plate. Is there a problem if they are not perfect?
Consider that many are post forming heat treated, actually I would expect it.
Now, what do you do, keep ordering more sets? No, you mark the bow and set that along the centerline of the bike.
Now you have to decide how you are going to miter this tube, to the "drawing" or to what exists, keeping you design goal in mind.
Are the 73° lugs you ordered, actually 73°? Material shrinks in the cooling process, due to the shape, they may not be… decision time.
My assertion is that after you have built a few you will understand that and where "letting things go" is better.
Not for the design important attributes, but for elements that do not matter.

If you fight the material, you may not keep what you fought for later in the build.
Framemaking is sort of like blacksmithing, but with calipers.

Blue Belly

i see your point, concerning tubing sets. Can you not return the bad tubes? After all, these are being used to build a very expensive machine.

repechage

In reading the various frame builder forums, it has to be really bad. Depending on how the tubes were obtained, domestic distributor or imported, the path of least resistance is to select a better one.
Due to the mfg. process, I actually would not expect perfection.
I have never seen a tube mfg. spec as to what THEY tolerate, probably proprietary.

Blue Belly

i know every industry is different but, if I built a guitar with the smallest flaw, it would be all over the Internet before I could defend myself with a reasonable explanation. Cosmetic, or otherwise.

repechage

As I said, it's blacksmithing with Calipers.

The brands and builders who get the heavy adoration here were guys that did just that.
The Taylor Brothers would hold a frame up to the window, sight off a muntin and if there was no visible daylight between the three lines, head tube, seat tube and window framework, call it good to go.
What I am saying is that a good, no, a terrific bike can be built with pretty basic tools and proper skill.
I am leaving out mass produced bikes, like the typical Raleighs, Schwinns, and similar of the period as very different methods were employed, tubes were notched, miters were approximate.
Heck, even for many trusted brands, take one apart after crash damage or even strip it of its paint and the reverence will fade away. Well, not fade, but there is a different appreciation of what went into making them.

Scooper's Waterford gets in my view quite a bit of appreciation as there is no paint, almost all the effort shows. A mistake will show.