Is it truly Columbus tubing? ..or just a decal?
 

Is it truly Columbus tubing?

I've recently run into an 80's steel mtb frame at the local shop. A Columbus off road/triplo spessore decal has been placed on the seat tube of the bike. The mechanic claims the seat tube, top tube and perhaps the down tube are Columbus steel. I've seen Columbus decals for sale on ebay so I'm a bit unsure what to think.

How can I found out if the frame is indeed Columbus tubing?
Is there a way to detect triple butted (triplo spessore) welds?

Best

I can do it by measuring the tube thickness in several places, but not many people own the tool required to do this (ultrasonic thickness guage)

What do the other decals on the bike say?
Look up the make and model in the manufacturers catalog and see what it says.

I don't know about Columbus MTB tubing, but in that period there were a couple of Columbus road tubesets with "rifled" splines at the bottom of the seat and down tube -- I would guess that they did this with their MTB tubesets as well. They've also done this with their steerers for a long time. Remove the BB and feel around the bottom of those tubes?

As Mudboy mentioned, Columbus SLX tubes were rifled at the bottom bracket. Sl and SP steer tubes were also rifled:

http://www.os2.dhs.org/~john/columbus-steertube1.jpg

You might also find the Columbus dove stamped in the steer tube, and on older tube sets, other tubes might also have the dove stamp:

http://www.os2.dhs.org/~john/columbus-steertube2.jpg

What about a magnet, it should have different degrees of attraction on the different butts, though the rifles could make that difficult to detect. You need a collection of magnets so you can have one that has a decent amount of attraction. Place in small bag with elastic attached and note how far elastic extends before bag falls off.

What is your concern? Is it cost, or are you feeling it would be a so much better bike if it had the Columbus? as far as cost is concerned, just beat him down if the decals look in any way sketchy. Don't pay for what is just a guess. If he can show some more reliable reason to believe in the tubes, then problem solved. Otherwise just negotiate your way past this. Can't prove it, it doesn't exist.

If your concern is mystical marketing BS, then is the bike good to ride. That will be 99% of it, the tubes are just sizzle.

Personally I would just show up with a puzzled look, and some of the ideas in this thread and use that to win the negotiation on price.

I'll keep my eyes out peeled for the ultrasonic thickness gauge, perhaps I too will own one sometime in the future.

[QUOTE=randomgear;14520376]What do the other decals on the bike say?
Look up the make and model in the manufacturers catalog and see what it says.[/QUOT

The make/model wasn't clear to me because the logos were weathered away. I'm going back to the shop this evening and I'll have more specs later tonight. thanks

I'll make sure to check the seat tube through the bottom bracket for the rifling. As well as look around the bicycle for the mysterious dove. Plus I'll make sure to use all of these techniques from the thread to figure my decision.

I'm trying to balance cost with durability because I'll be riding the bicycle across the States this fall season. Since I just became a member last night, after posting my first thread I'm really amazed with the knowledge of this community. Thanks!

I'll let you know what I find when I'm back from the shop.

Best

I was going to say that I didn't think you could get those particular columbus decals, but then I found some very similar ones on ebay :)

Doing some quick research it looks like SuperGo Access Team came in both steel and aluminum. The SuperGo Access Comp in this thread has the same Columbus Off Road tubeset sticker you described. The Columbus logo is even incorporated into the model decals.

You stated that the decals on the frame were worn, does the columbus decal match the same wear or is it newer? If its got similar wear its less suspicious.

I recently built a frame with Columbus Chromor OS tubes. No rifling, no dove stamp.

The was a recent discussion on butting gauges on the framebuilder's mailing list:

Michael Slater (Singapore) Jun 10, 2012

Recent threads about tube butting gauges got too complicated for me to follow. I didn't think it should take Wolfram Alpha to figure out how to build one, so I dug around my scrap bin this weekend and found a bunch 1cm-square stock.

I filed a bolt to a round tip, and used a dial indicator from my mill for the measurement end.

I originally just brazed the two cantilever arms on without additional bracing, but the result had too much slop and the measurements were useless

So I c-clamped an adjustable parallel between the two cantilevers, 20cm back. That stiffened up substantially. I measured a HOXPLAT04 True Temper tube blind, and got the same butting measurements within a centimeter of spec, so the gage works.

So today I added the additional bracing shown to give it some more rigidity. And I gave it 30cm of room for deeper butting profiles. Done.

(It was also enlightening to use my torch at way more ferocious levels than I do with bicycle tubing)


http://www.os2.dhs.org/~john/butting-gauge-1.jpg
http://www.os2.dhs.org/~john/butting-gauge-2.jpg

funny, that looks exactly like mine. It's too wimpy though. I want to make another one

The device illustrated is of course entirely useless if the tube you want to measure is part of a bicycle. That's when the ultrasonic tester becomes the go-to method.

It's also much easier to get accurate results as there's far less to go wrong.

we were calculating the wavelength of sound in steel the other day, and it's about 1mm at 5mHz. That's why the limit on thickness is about 1mm for the cheap thickness gauges you see on ebay. I'm thinking this would cause a problem for using most of the cheap ones on bike tubing. How well do they actually work?

The trick is to use an echo / echo gauge such as the Nova 900 series. Instead of measuring the delay between the pulse emission and echo they measure the time delay between successive echos. I think they measure phase angle differences to enable resolution within one wavelength. The one I use appears to be OK down to about 0.1mm and by the time your wall thickness gets there....

Successive phots show ultrasonic gauge and micrometer measurements for two areas of this tube which has been surface ground. Note that the unit was designed to display in imperial units, you can change it by re-entering the appropriate velocity so I have it displaying in centimetres. Newer units (900 series) will display in both modern units and imperial units

http://bikeforums.net/attachment.php...hmentid=263514

http://bikeforums.net/attachment.php...hmentid=263509

http://bikeforums.net/attachment.php...hmentid=263510

http://bikeforums.net/attachment.php...hmentid=263507

The agreement is pretty good.

http://bikeforums.net/attachment.php...hmentid=263635http://bikeforums.net/attachment.php...hmentid=263636We have two different results with the dial indicator butt gauges and the ultrasonic micrometer. The dial gauge will not tell you the actual wall thickness, it will show you the butt transition very well and suggest an aproximate wall thickness. But when a tube is slid over a dial gauge it will drop from the weight. On my stiffer version two that drop is as much as .005"-.006", wall thickness and diameter (or tube mass) dependent. There are tricks you can employ to "calibrate" this drop but they are aproximations only. It looks like the ultrasonic mic. will measure actual wall thickness. But it would need to do a number of measurements along the tube's length to find the start and finish of the butt transition. Will it do a "running readout"? Or will each point require it's own moment of measuring?

here's a couple of shots of my two dial butt gauges. Photo #1903 is version #1, now sold and gone. #1119 is my current one, with changes learned from #1. Andy.

Andy, you may have set the record for world's longest butt gauge. Looks like #1 would measure both butts, is #2 long enough to do that?

OT: wish I had bought a Kennedy toolbox back when I could afford one

Eric- Well, you do know that one can discern the length of a man's... I should have made #2 a few cms longer butt I'm happy with how it works. (bad pun). WRT the kennedy boxes. I got my 1st one back in 1977. Now I have a number of them. Too many as some draws are empty. This means I need more tools though. It's a hard world! Andy.

Response time is finite but fast enough that sliding the sensor along the tube gives a useable series of readings as long as you can hold the head in the correct orientation. The limitation is couplant: it's not shown clearly in my phots but there must be a couplant between the sensor and the material for it to work properly, so if the couplant runs out while you are sliding you lose measurements. I use ordinary "personal lubricant" as couplant because it's cheap and easily available. This will work for a slide of 100mm or so, the real stuff might be better.

Even with my limitations , if you do a couple of spot measurements to work out the rough location of the butt transitions then slide across the area you'll get an exact location for the transitions. Also the face of the sensor is a relatively soft material, epoxy I think. Too much sliding and you are up for a new sensor: they're not expensive but they're not free, I suppose you could simply repair the epoxy but I haven't tried that.

Phil Wood grease makes a great couplant. Too bad it's getting so expensive. I have some vacuum grease that works pretty well too, but I somehow misplaced that.

I have access to a lot of ultrasonic equipment, I should try it out. For locating butts, you don't even need a proper thickness reading, it's the relative reading you are interested in.

I took a picture of the tubeset box and pile of parts that I built up .

Op bought a used bike