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Thread: Primum Multorum

  1. #1
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    Primum Multorum

    I've completed my first bike! Kudos to those that pick up on the name (without Google), but it sums up how I feel about it. Many thanks to those of you contributing knowledge for us to make decent bikes! The proud new 96er.



    By standards here, I have a ways to go. I thought through a good portion of it, but from seatstays on, I was winging it. It shows in some spots. I still don't know how to get brake stays on well. I really wish I could find all of those WWTP threads! They seemed to have aged out of the search. I have a feeling that would have helped me out lots to see how Jay got through/talked through it.

    The first steps, when I had access to a ridiculous dream table, went well. The main triangle came out pretty darn solid with the exception of the welding. You guys definitely made me a better welder from reading your posts. The suggestions to gas lenses and prep changed my oxidation, my practice made things better but I still lack consistency and heat control.





    The bike was out on a few rides before I painted. It was a delight to ride! I've been riding the same straight gauge Specialized (where all my parts traveled from) for the past 15 or so years, so this was a step toward the modern world.

    The semi-incomplete... forks are sketchy. I learned about the HOXPLATST5... I'm eyeing some AVROBST-649 for the second one (suggestions?), and they can correct a little geometry change. In the mean time, to get it out and rolling, I did an ugly sleeve job for the forks.

    Again, thanks to all of you for a great base of knowledge.

  2. #2
    Bike Freak
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    The bike looks great!
    Quick question regarding the fork, when you swing the bars around 180 degrees do the top caps of the fork contact the down tube?
    If so be careful, with a bad wreck your fork could destroy your downtube!
    My bikes [Fe][C]ycles

  3. #3
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    I destroyed my second-ever frame (the first I built for myself) in just this manner. Amazing what the top of a fork blade will do to a downtube in a hard crash...

    Also, just FYI, if you do destroy your downtube that way, don't bother trying to ride the bike out, no matter how gingerly, unless your goal is to finish the job so you can strap it to your back more easily. Nothing like walking 8 miles with a bike with your name on it strapped to your back in 2 pieces to make you feel truly wretched...

    Back on topic: Looks very cool, and as usual, your first is much better than mine was. Care to share geometry numbers? Why the mixed wheel sizes?

    -Walt

    Quote Originally Posted by jgerhardt View Post
    The bike looks great!
    Quick question regarding the fork, when you swing the bars around 180 degrees do the top caps of the fork contact the down tube?
    If so be careful, with a bad wreck your fork could destroy your downtube!
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  4. #4
    Nemophilist
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    Congratulations!

    I read EVERY one of Jay's WWTP threads before starting my own odyssey. At the very least, they helped calm lot of my fears about diving into the unknown, and were an invaluable resource. There in the footsteps of another clueless traveler have gone many of us since. They should be collected and posted permanently, somewhere!

    I have so far not found the courage to do my own fork. Perhaps that is an irrational fear, but I hope it is at least a logical one. Something about the front end collapsing and disappearing from under me I find less than appealing. The rest of the frame tubes have help in their task. I guess it is all that... unsupportedness that bugs me.

    Although I can't claim to know much about it specifically, I too would be interested in the geo. It is interesting that after 15 years of riding the same old technology, you chose an evolutionary dead end as your next platform. I'd be interested in how you arrived there, how you came up with the numbers you did, and why.

    Cheers on completing #1!
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  5. #5
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    Regarding the geometry, I did 71 deg. for the HT, 73 for the ST. The CS is 425mm with 30mm drop to the BB. I just did a survey of some production and semi-custom bikes to get some basic numbers. I really don't have a clue what my preference is since I've been riding the same slightly small frame forever, and figured I had enough time ahead of me just making the bike. As I play around, I'm sure I can figure out something more optimal for a later, more serious, and better bike.

    I thought the 96er would give me some benefit of the larger wheel rolling over choppy objects while not having the inertia in the rear. I don't know much about its past, but it seemed interesting enough. Initially, I had thought about a 650 up front, but finding 650 rims for V-brakes also goes to the evolutionary dead end. I already had a Delgado Cross sitting around, so I made use of it.

    Yes, the fork tubes will contact since I didn't chop off the top. I do intend on cutting and finishing the next set. I don't expect to be riding it hard enough to worry about it, and maybe not at all, until my IRS savings fund comes back for new materials. Historically, I reserve the big swap lock up and OTB crashes for the motorcycle. I'll keep your suggestion in mind Walt, if I happen to have tempted fate too much now.

    TM, if anyone can do high quality fab work for a fork, I think you qualify! I've gone back and forth on being afraid of building a fork. But, I've had a production fork bend on me, so I guess some of that fear left with it. Also helps that there isn't really any aggressive riding around me. If I were bombing down the mountains, I would have a different view. But as it is, I haven't even really missed my front brake.

  6. #6
    650b me
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    Congratulations on your first frame, and thanks for sharing! I know a local (Denver) guy who builds 69'ers, so you are not alone. I've never ridden one, so I won't knock 'em. I'd love to see more photos of your build process if you care to share. Good job!

  7. #7
    Nemophilist
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    Hey LF;

    Sounds like a reasonable thought process. I'm one for using what I have around too, where applicable. I call it the Farmer Mentality, although I admit to doing none of that on the Kroozer. I had some friends back in the very early 9er days that did 69er conversions on the Scalpels/Lefties, and they noticed a huge difference in forward roll. They rode them for quite a while. I guess if you get used to front forward roll only, it is not a big deal.

    Don't even need a front brake? Wow... it would never occur to me. I tried a 6" front rotor on my Humvee because... it's what I had around. Nope. Couldn't even stay slowed let alone get stopped.

    Front fork. Let's just say I have more than a casual interest in self preservation. If I could guarantee that if it failed it only bent....

    Your bike looks like it has a very high front end/long fork (could be just the pic, or that big front wheel). Is that intentional, or is that the "little geo change" you mention?

    Regardless, it's cool that you've joined the ranks!
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  8. #8
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    Quote Originally Posted by LemonFool View Post
    I really wish I could find all of those WWTP threads! They seemed to have aged out of the search. I have a feeling that would have helped me out lots to see how Jay got through/talked through it.
    Yeah, I was looking for one the other day and couldn't find one no matter what I searched for. I think the upgrade to MTBR broke some stuff perhaps-don't know.

    I'm searching for a post Fattic made the other day right now and can't find it either. It's frustrating.

    Cool project BTW! Congrats on #1.

  9. #9
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    I think the WWTP threads timed out. I couldn't find anything beyond two years back no matter how hard I tried. I couldn't find them well before the swap over.

    TM, the little geometry change comes from me not getting the right lengths with the tubing's minimum butts and dropout adapter I ended up making. No more double butted tubes for me up front. The angle probably makes it worse.

    I went back and found surprisingly few pictures of my build.

    This is the table with jigs lined out. I'm a little bummed I didn't get any of the chainstays going in. The rear threaded down to the table to hold the dropout in place, and a nut on top took care of the upper. I made the DO the right width for it to all be centered. Came out pretty well.


    The machined adapter for the front DO to tubing. I don't plan on doing this again. The offset is too little for a disk hub. I'll just machine one that offsets to the edge of the tubing.



  10. #10
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    Lemonfool

    I live in oklahoma and built over 100 frames in the 90's. I am looking for a tig welder so I can build again. Send me a PM if you like some ideas on how I built frames.

  11. #11
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    I got your PM but I have not made 10 posted here so I can not reply to pm's. I would not invest to much time or money in a fixture to weld the frame. I used very few fixture to build frames. I built sub assemblies then welded them together. I found if you put the tubes in a fixture and tack it together then weld it, you build in a lot of stress into the frame. Lugs or fillet brazing need a fixture to hold things in place tig you can tack tubes and check them for alignment before welding. I would miter the seat tube and weld it to the BB shell then cut the seat tube to length and silver braze the seat collar. Next cut the head tube to length, miter the down tube and weld it to the head tube. Next miter the seat tube to fit the BB shell and make sure it is square. Next miter the down tube to fit the seat tube and weld it to the BB Shell/seat tube. Now check the frame and see if you need to make the top a little shorter or longer. You do not want to bend the down/seat tubes to make the top tube fit. This way you will not have stress already in the frame before it is used. Also you need to check alignment of the seat and down tubes and make any adjustments before the top tube is welded. Last miter the chainstay's and tack them and the dropouts in place and weld the chainstay's to the BB shell with a axle in the dropouts. Last put the seat stays on and weld them. Before brazing the dropouts I check the rear triangle for alignment and make some adjustments if need by heating up the tacks or cutting them and tacking before brazing or welding.
    Last edited by Integrexman; 02-28-2013 at 02:39 PM.

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