Can anyone explain hvow to use the tube spec. I can’t figure out the principle of the sections and the relation to the total length. The seatstays er even more confusing??
Butted tubes have the differing wall thicknesses separated by a tapering wall thickness portion, 50mm is a common length of the taper as example. So the tube begins with a set wall thickness for some length, then the taper section for that length, then the (usually) thin central section of the tube for some large length, followed by a second tapering wall section and the ending thick wall section. Each section is called out by the length and usually the tube will have some indicator to which end the factory considers the “starting” one. For a single butted tube the central thin walled section will continue to that second tube end. Externally butted tubes are specified much the same but with the added wall thickness at one/both ends being on the OD, not the ID as is more typical.
XCRL12650 35 650 0,65/0,45/0,65 40 40 430 40 100 XCr
This is a Columbus XCR down tube. It is 35mm in diameter, 650mm long, with butts of .065 for 40mm, then the transition over the next 40mm, then the thin .045 wall for 430mm, the second transition of 40mm and the thick end (the one intended to be cut) of .065 wall for that last 100mm.
Most tubing companies offer similar specs. The above is from the current Columbus site Diagonal Tubes – Columbus Andy
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Ok, thanks. Still wondering, but I will have to play with it. I still dosen’t make sense when the tube are with internal butting?
The butting spec doesn’t care whether the butts are internal, external or both. Just where they start and stop WRT one end of the tube.
I’ll add that these butt profile specs are usually correct there are times when “things” happen and the tube doesn’t meet the specs. This is why one of the tools I built long ago was a butt checker to double the butt locations, especially important when dealing with really short tube lengths. Andy
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Have been trying to make sense of it again, but can’t. When setting a tube up as parallel (no buts or internal)locks the bokses, so that I can’t put in the numbers I want. When trying to use the data for an externalbutted seattube the numbers get changed and the length of the sections is not accepted???
It seems like I always have to activate the next section aften the one that should be the last, to get results??
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Dan Chambers
It sounds like you are using some frame design program and not actually playing with a tube in hand.
What do you mean by “When setting a tube up as parallel (no buts or internal)locks the bokses, so that I can’t put in the numbers I want”? If you’ve explained this all before I apologize but taken as a stand alone it’s confusing to me. Andy
When i try to input the data for a Zona seattube evrything is fine before updating.
When i update the data changes and i end up with the wrong messurements.
I thougt that if you where using a non butted tube(or internal) that you could use the init/parallel to set up a simple tube and get the correct miter templates, but I can’t get it to work???
This had me confused too until I spotted it was in the RattleCAD forum.
I’ve used RattleCAD alot and never quite understood how that menu works. I just enetred numbers until it got to where I wanted it. My licence ran out and it was too complicated to renew so I’ve dropped and just use AutoCAD now. Sorry that’s no help, but I couldn’t figure that pallet out either to be honest.
DEVLINCC maybe not helpful in regards to using RattlrCad, but helpful for my selfesteem 
I can’t make any sense of it, so I’ll just go with the enter numbers til it works method.
Last time i used RattleCad was when there was a free version, and i likede the miter templates, for my latest projekt I made the miters using a online calculater, it was a lot of work, so i bought a license for my current project so i can get the templates for mitering by hand.
So i just need to make it work not make sense. I can always check the templates before cutting.
I’l;l see if I can get my version working and have a look. From memory it was influenced a lot by the active box being checked or unchecked.
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