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  1. #1
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    Source for Boom Tubes???

    Since the Suppliers thread is closed; posting a new thread of need here:

    ISO a viable source for large oval tubing, such as would be used for boom tubes in tandem construction?

    I am about out of old stock and the two companies in the US which used to produce them have elected to not do so anymore.

    While we can order them from Ceeway in the UK for USD $42 each plus shipping, my goal has always been to source everything practical from US based producers.

    So if anyone knows of a source, would appreciate a posting. If it is a secret source then a PM would be fine also.

    Thanks
    Kerry

  2. #2
    tuz
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    On eBay, Ti Cycles sells a ovalized 1.75x0.035x30 boom tube. Looks like it is more expensive than the Ceeway option, but it is likely lighter (and equally stiff).
    homebuilt commuter, mixte, road and track (+ Ryffranck road)
    bla bla blog

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    Randomhead
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    don't they still sell boom tubes at HJ? I would probably just use a 4130 tube though. The Reynolds 531 tube on my tandem looks undersize to me now.

    I closed the suppliers thread because it's just for contacts for suppliers. If something needs to be added to it, PM me. Thanks

  4. #4
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    Quote Originally Posted by unterhausen View Post
    don't they still sell boom tubes at HJ? I would probably just use a 4130 tube though. The Reynolds 531 tube on my tandem looks undersize to me now. I closed the suppliers thread because it's just for contacts for suppliers. If something needs to be added to it, PM me. Thanks
    I communicated with HJ; said used to make them but don't make them anymore.

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    Quote Originally Posted by tuz View Post
    On eBay, Ti Cycles sells a ovalized 1.75x0.035x30 boom tube. Looks like it is more expensive than the Ceeway option, but it is likely lighter (and equally stiff).
    I looked there based on your input. I didn't find any oval tubes.

    Also I am looking for classic ChroMoly tubes, either straight gauge or butted, i.e., am not in need of Ti or AL or CF or bamboo or plywood or cardboard or fiberglass tubes. Sourcing for those alternative materials would be helpful to other builders so appreciated if folks could forward any sourcing for those to unterhausen for adding to the suppliers thread.

    Thanks
    /K

  6. #6
    tuz
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    here is the link.
    homebuilt commuter, mixte, road and track (+ Ryffranck road)
    bla bla blog

  7. #7
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    Quote Originally Posted by tuz View Post
    here is the link.
    Tuz; my apolgies as I missed your attempt to point me to the ebay. I looked on the companies homepage and found no ovals. But I had seen the ones on ebay several weeks back. I communicated with the seller and made a reasonable offer which was turned down. At last look the tubes are still there awaiting a buyer. I just felt $70 per was way too high. I also felt that the tubes were not ovalized enough to provide any advantage over a round tube. I looked at all my current tandems and all their booms are effectively the same shape...all are significantly flatter than the ebay items. The stock that I mentioned as being 'run out of' follows closely to the built production bikes I have. Thanks for the attempted assist.

    /K

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    I suspect a round tube is actually stiffer than a extremely ovalized tube. The old Reynolds tubes look nice, no doubt about that.

  9. #9
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    Quote Originally Posted by unterhausen View Post
    I suspect a round tube is actually stiffer than a extremely ovalized tube. The old Reynolds tubes look nice, no doubt about that.
    The purpose of oval boom tube was to get as close to the full width of the BB as practical which increases the lateral strength (reducing whippiness) while also not being so large in the vertical dimension as to be taller than the rear BB shell (which makes it difficult to finish off the rear well). When most bikes were barely hi-tensile steel, one did what one had to to get rid of lateral whippiness.

    In the 70's I saw 2bikes made with rectangular bottom tubes and some that were made with a pair of Reynolds 531 downtubes sitting side by side. Both examples brought streams of derision from viewers who compared them poorly to the prime example of the day (the Taylor Bros tandems).

    /K

  10. #10
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    I thought Phil Wood [used?] to sell rolled into an oval tubes.

  11. #11
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    I think if you look through the NAHBS tandems, that most of them are using a larger, round, 4130 tube. I love the way the old reynolds oval boom tubes looked, but they aren't as stiff. People are used to it now that tandem builders have been doing this for decades. You aren't bending the boom tube in the major dimension of the oval all that much. I think they did it that way so they would fit a larger tube on a bb shell, and that's an issue with a round tube of similar section. You have to remember that when the Reynolds tandem tubing set came out, it was the only set of tubing with oversize tubes on the market. We were so set in our ways that Klien actually sued Cannondale over using larger section tubes, it was so unheard-of. I find it hard to get over the old ways, but I usually manage to force myself if the new ways are better or even just easier to source.

  12. #12
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    FWIW, I was involved in building a racing tandem a few years ago, we ended up using a 38mm mtb down tube that we
    ensquishened(tm) to fit the rear bb a bit better. It was raced by some seriously strong guys and was plenty stiff.

  13. #13
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    Quote Originally Posted by unterhausen View Post
    I think if you look through the NAHBS tandems, that most of them are using a larger, round, 4130 tube. I love the way the old reynolds oval boom tubes looked, but they aren't as stiff. People are used to it now that tandem builders have been doing this for decades. You aren't bending the boom tube in the major dimension of the oval all that much. I think they did it that way so they would fit a larger tube on a bb shell, and that's an issue with a round tube of similar section. You have to remember that when the Reynolds tandem tubing set came out, it was the only set of tubing with oversize tubes on the market. We were so set in our ways that Klien actually sued Cannondale over using larger section tubes, it was so unheard-of. I find it hard to get over the old ways, but I usually manage to force myself if the new ways are better or even just easier to source.
    U-Man; No argument on your points. Spot on. I am well aware of the bow-wave caused by the advent of the Taylor Bros driven Reynolds 531 butted tandem tube set. Was there then and wanted them bad (for all the good it did me to want). And as a student I couldn't come close to the cost of a built Taylor tandem.

    I built my first bike frame (a full sloping top tube tandem for personal use) in 1974-76 from a mix of available tubes; a 1 3/8" chromo downtube, a 1 3/4" round chromo straight gauge boom tube, two 531 HD seat tubes, 531 HD double butted single bike downtubes for all the rest of the tubes, a full sloping cinelli cast crown and the strongest set of Reynolds stays and blades I could get.

    I built my first set of bike wheels for that tandem; Phil Wood 48-spoke bolt-on hubs, 27 x 1 1/4" Weinman A129 concave rims and stainless 14g spokes. A Shimano disk and a brace of Mafac canti's provided the stoppage via a set of dual pull levers.

    Even though #1 build was an XLg/Lg (25"/23" seat tubes) with maximum length top tubes it was very stiff in all dimensions and tracked perfectly even of steep climbs and descents.

    Some regrets looking back were;
    1) Setting aside my math results and going with the trend of 130mm rear OLN instead of 145mm (Phil would have made the hubs for 145 at the same cost as 135mm);
    2) Not following my instinct which told me a direct lateral tube was the best reinforcement adnd instead going with the trend in running the lateral tube line to the rear dropout. Proud to say that I didn't use the typical 1/2" 'sketti tubes, instead I used 531 HD butted single downtubes back to the stokers seat tube and then an extra pair of HD Reynolds chainstays back to the dropouts with the extra CS length employed to overlap the ST and the rear lateral tube by about 3 inches (lots of brass used at that joint).
    3) Letting the bike go and losing track of the jig when moving on from college to the real world... once in a while I will still take out the faded and smudged full scale drawings and stare at them... but enough memory and history for today.

    /K

  14. #14
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    Quote Originally Posted by Live Wire View Post
    FWIW, I was involved in building a racing tandem a few years ago, we ended up using a 38mm mtb down tube that we ensquishened(tm) to fit the rear bb a bit better. It was raced by some seriously strong guys and was plenty stiff.
    LW (and also U-Man); Tending to trend to that same conclusion (when the customer doesn't demand a classic looking boomer such as was quoted by Ceeway (in UK): Oval classic tandem boom tube made to order from ~1.75" chromo; 30" long x ~1mm wall; $42 per plus shipping to USA

    Prior to getting the quote from Ceeway, I was developing a series of alternatives to the classic oval tube;

    These looked promising as feed stock;

    1) Fm Nova; NOV_CODT_42_858, 29ER MTB DT, 42mm (1.65") x 750mm (29.5"), 8/5/8, 110 & 150mm butts; $27.34 per
    2) Fm HeneryJames: MHT44-L, 46.4 mm (1 7/8") x 1,524mm, 1.25mm (bulk headtube material), $50.75 (cuts into 2 each 30" boomers)
    3) Fm Pacenti; #1582, 44.5 x 700mm (only 27.56" long), 1/7/1, (OX PLAT), On-sale for $10.00 per tube
    4) Fm HeneryJames: BMXST-DT06, 44.5 mm (1.75 ") x 700mm long, (only 27.56" long), 1/7/1, 100mm & 265mm butts; $28.35 per

    Given the bottom brackets which intersect the boom tube;
    Rear BB: 69mm width x 38mm diameter <<<<< the problem
    Front BB: 61mm width x 59.8mm (2.355 inch) diameter <<<<< not a problem

    Then some ovalizing will be needed, at least for the rear BB end.

    I am sketching out a jig/fixture to do this 'ensquishening' (tm/LW). It currently looks like a stout bolt on collar to match the selected boob tube diameter(s). Pivoting on 1/4" pins from flanges on the top and bottom of that collar would be a pair of right triangles (cut with a diagonal slice through a single bar of 2x2" x 12" long T6 aluminum. The goal being to put the jigged up tube in a large bench vice or hydraulic press and squeeze it until the end of the tube in squished oval enough to be less than the 38mm diameter of the rear BB. Thinking also that the nice slope on the resultant boom tube would provide a nice/better landing zone for the lateral tube coming in from above at an angle. I would probably squish the tube for the front ECC BB also, even if just to be a contrarian/romantic. Call it a "dog-bone" bottom tube?? Why not. Someone has already done this for sure...

    I should have the sketch finalized by this weekend and a wooden prototype done by next weekend (PM me for jpeg pictures if desired) and will I post to the 'we made jigs/fixtures" thread when its clean enough to share (i.e., after first successful squish from a round tube...so in about 3 weeks as I have to select a candidate tube and get a sample shipped in to squish on).

    /K
    Last edited by ksisler; 02-01-13 at 12:06 PM.

  15. #15
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    Anyone know a cheap source for oversize 35 thou tubing. Or tubes that could be used make folders like the BF.

    http://www.kcdawnpatrol.org/Oval_Press.htm

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    Quote Originally Posted by MassiveD View Post
    Anyone know a cheap source for oversize 35 thou tubing. Or tubes that could be used make folders like the BF.

    http://www.kcdawnpatrol.org/Oval_Press.htm
    Buttered or straight gauge?

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    I heard BF was straight gage.

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    Quote Originally Posted by MassiveD View Post
    I heard BF was straight guage.
    Aircraft Spruce has fairly large straight gauge up to 2.5 inch. Problem in closing on your original question is that most tubes available in larger diameters are thicker walled which isn't needed for most bike building... Even .049 dries up quickly as the size goes up. 2.75" in 1/8" wall for $28 per foot (ouch!!)
    http://www.aircraftspruce.com/catalo...tubing_un1.php

    Nova has several Columbus butted down tubes up to 42mm diameter
    COLUMBUS LIFE 42mm X 6/4/6 and 29er DT 42 x 8/5/8 x 750 and they are cheaper than the above mentioned generic straight guage. I think somewhere on that site is 48 or 50mm Columbus, but I couldn't find them now

    One of the the suppliers has big butted DownTubes on sale for $10 each

    Hope that helps
    K

  19. #19
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    I would worry about ensquishening butted tubes unless you can get something with longer than normal butts.

  20. #20
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    Quote Originally Posted by ksisler View Post
    LW (and also U-Man); Tending to trend to that same conclusion (when the customer doesn't demand a classic looking boomer such as was quoted by Ceeway (in UK): Oval classic tandem boom tube made to order from ~1.75" chromo; 30" long x ~1mm wall; $42 per plus shipping to USA. Prior to getting the quote from Ceeway, I was developing a series of alternatives to the classic oval tube;
    <Yadda Yadda snipped for brevity>
    I am sketching out a jig/fixture to do this 'ensquishening' (tm/LW). It currently looks like a stout bolt on collar to match the selected boob tube diameter(s). Pivoting on 1/4" pins from flanges on the top and bottom of that collar would be a pair of right triangles (cut with a diagonal slice through a single bar of 2x2" x 12" long T6 aluminum. The goal being to put the jigged up tube in a large bench vice or hydraulic press and squeeze it until the end of the tube in squished oval enough to be less than the 38mm diameter of the rear BB. Thinking also that the nice slope on the resultant boom tube would provide a nice/better landing zone for the lateral tube coming in from above at an angle. I would probably squish the tube for the front ECC BB also, even if just to be a contrarian/ romantic. Call it a "dog-bone" bottom tube?? Why not. Someone has already done this for sure...

    I should have the sketch finalized by this weekend <snipped for brevity> /K
    Ok got the sketch done: Ran with the poffered "round tube approach" but didn't accept all of it. Oval on the ends with round in the middle for a "dogbone tube" to make everyone happy. I ran the numbers and found that 1.75" round stock results in a bit too small of an oval so switched to 2 inch round stock. Didn't differentiate whether it was straight gauge or butted tube.

    Here is the math (trick is to use all the circumference of round pipe in its new oval shape by guessing the two dimensions of the oval and seeing if its circumference matches):

    Ensquisherator to produce boom tubes - the math_small.jpg

    Here is the first sketch for the Ensquisherator (TM LW):

    Ensquisherator Sketch to produce boom tubes_small.jpg


    Using a 2" tube and squishing it gradually into a 2.40" x 1.5" oval looks like a good fit to the face of a 2.67"w x 1.61"h rear BB tube. Would seem to be ok for mating the tube up with the ECC shell up front also. The squish stop block shown in the diagram is to give me a squish past stop and then let the pressure off and see how much the tubing rebounds. Some trial and error required to get it to rebound and stop at the right 1.5" size...will probably waste one 30" piece in testing (I'll cut one in two and give it two trials).

    Thoughts/comments?
    /K

  21. #21
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    Quote Originally Posted by unterhausen View Post
    I would worry about ensquishening butted tubes unless you can get something with longer than normal butts.
    U-Man: Agreed. While I think the Reynolds tandem tube was butted and that the Tange tube that Santana used was also, but I have never seen the math done to show that a butted bottom tube benefits* a tandem that much. Anyone got the facts?

    /K

    Added 12 Feb; (*outside a scant ounce or two of weight)
    Last edited by ksisler; 02-12-13 at 07:54 AM. Reason: additional thought

  22. #22
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    Quote Originally Posted by MassiveD View Post
    Anyone know a cheap source for oversize 35 thou tubing. Or tubes that could be used make folders like the BF.

    http://www.kcdawnpatrol.org/Oval_Press.htm
    Massive One; Apologies for commenting on your call for tube without actually hitting the URL. That Oval press might be just the ticket for my panderings for oval boom tubes, downtubes, continuous top tubes, etc.

    Making the leap that this is a pix of your press... Are you sort of volunteering to enquisherate for hire....or should I build one of the presses and become more self service-ing?
    /K

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    I have been using 29er down tubes from Nova cycles. It is about the only tube I have found long enough and now they have them in various thicknesses. Ovalize the one end.
    Last edited by 1930harley; 04-17-13 at 07:01 PM.

  24. #24
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    Quote Originally Posted by 1930harley View Post
    I have been using 29er down tubes from Nova cycles. It is about the only tube I have found long enough and now they have them in various thicknesses. Ovalize the one end.
    '30; Agree. For boomers, the length is a constant issue. I had also been looking at those tubes already as strong solutions for some of the other tubes for stout tandems. Prices look good also.
    /K

    PS; Apologies for being out of the shop for a bit as I had to deal with life issues for a few months instead of holding the torch and manning the files.

  25. #25
    WPH
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    Quote Originally Posted by ksisler View Post
    U-Man; No argument on your points. Spot on. I am well aware of the bow-wave caused by the advent of the Taylor Bros driven Reynolds 531 butted tandem tube set. Was there then and wanted them bad (for all the good it did me to want). And as a student I couldn't come close to the cost of a built Taylor tandem.

    I built my first bike frame (a full sloping top tube tandem for personal use) in 1974-76 from a mix of available tubes; a 1 3/8" chromo downtube, a 1 3/4" round chromo straight gauge boom tube, two 531 HD seat tubes, 531 HD double butted single bike downtubes for all the rest of the tubes, a full sloping cinelli cast crown and the strongest set of Reynolds stays and blades I could get.

    I built my first set of bike wheels for that tandem; Phil Wood 48-spoke bolt-on hubs, 27 x 1 1/4" Weinman A129 concave rims and stainless 14g spokes. A Shimano disk and a brace of Mafac canti's provided the stoppage via a set of dual pull levers.

    Even though #1 build was an XLg/Lg (25"/23" seat tubes) with maximum length top tubes it was very stiff in all dimensions and tracked perfectly even of steep climbs and descents.

    Some regrets looking back were;
    1) Setting aside my math results and going with the trend of 130mm rear OLN instead of 145mm (Phil would have made the hubs for 145 at the same cost as 135mm);
    2) Not following my instinct which told me a direct lateral tube was the best reinforcement adnd instead going with the trend in running the lateral tube line to the rear dropout. Proud to say that I didn't use the typical 1/2" 'sketti tubes, instead I used 531 HD butted single downtubes back to the stokers seat tube and then an extra pair of HD Reynolds chainstays back to the dropouts with the extra CS length employed to overlap the ST and the rear lateral tube by about 3 inches (lots of brass used at that joint).
    3) Letting the bike go and losing track of the jig when moving on from college to the real world... once in a while I will still take out the faded and smudged full scale drawings and stare at them... but enough memory and history for today.

    /K
    Ksisler that is really interesting. Have you shared this information on the tandems forum here at BF? I am sorry you have regrets from this experience, but in light of your point number 3, I can totally understand why.

    Bravo you for building a twicer as your first frame.


    WPH

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