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  1. #1
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    First frame building project - what I learned as a noob

    So my first frame project is going on (see here) and so is the learning process. This forum has been so helpful to my progression that I feel like wanting to give something back. So the goal of this thread is to share what I learned in MY process. YMMV.

    To give you some background, I started as a total noob with respect to welding/brazing. I do have some mechanic background and fairly extensive bike mechanic experience.

    I have what I would qualify as a basic work shop with most hand tools (hacksaw, files, bench vise, etc) and some power tools (abrasive cut off saw, drill press, hand and bench grinder) but I have no access to heavy metal working equipment (milling, lathe, bending or rolling tubes)

    I started this as a hobby and have no plan to make a business out of this. I plan to build 1-3 frames a year. I have no plans of making forks. My main and so far only planned building method is fillet brazing and silver brazing for the braze ons. I don't plan to TIG nor to use lugs. I made this choice based on versatility, initial investment and learning curve.

    I used a full on 3D CAD software to model my first few frames and although this has helped me a lot for planning, it is absolutely NOT essential as many have proved out on this forum. Once I get more comfortable with frame layout in general, I plan on using BikeCAD exclusively.

    So all that being said, what did I learned so far?

    If I started over again, here is what I would do differently:

    • Buy a smaller aircraft type torch set right from the start. I knew I was only going to build bike frames. I already feel how big and clunky my auto part store torch is.
    • Invest in a flat surface rather that a 8020 frame jig. My first frame isn't straight (measured by eye and with a string). Nothing that will make it unridable and probably even not noticeable while riding but still; since I don't have any means of measuring it *precisely* , cold setting is kind of impossible/pointless. Then again, I know I don't want to get over obsessive with precision. A good discussion on the subject can be found here: Sources for a flat surface for framebuilding


    What I'm glad I did:

    • Research, read, learn - a lot. This forums is filled with great info and people willing to share their knowledge. Google has also been my friend. I read Tim Paterek's book and would recommend it to anyone starting out on this.
    • Practice, practice, practice fillet brazing. My brazing is still far from excellent. But with practice joints, I could mess around and try different "technique" and set ups and test their strength/cut them open to see how I did.
    • Make myself some wood tubing blocks. They're not square, they're ghetto, but they are essential for the never ending miter dance; file/check/file/check/file/check/file/check...First frame building project - what I learned as a noob-pb200042.jpg
    • Choose a simple first frame. I made some mistakes, it's unavoidable. The simple design minimized the traps I could fall into
    • Buy my supplies from very helpful sources with great customer service (HJ, Nova, PMW, Cycledesignusa)


    What I want to do for my next build:

    • Make myself a chain stay jig. I had a hard time getting the miter of the CS square with the BB and the wheel dead center between them.
    • Make myself some SS/CS bending apparatus. Next build up are fat bikes... 5" tires require some CS/SS lovin'
    • Shop for a smaller aircraft type torch.


    Hopefully, this is helpful to someone wanting to jump in! Others, feel free to add your own list of learning's.

  2. #2
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    First frame building project - what I learned as a noob

    Nice work! Thanks for sharing. Threads like this helped me a ton too when I was starting out. Starting with a flat plate instead of a frame jig is a tough one but I completely see why you would go that route.

    What was your process you followed for brazing it up? Did you tack it up in the fixture or did you follow Paterek's method of brazing in subassemblies? What does your frame fixture look like?

  3. #3
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    Good job so far.
    I'm dealing with CS bending, i've done 2 Knard tire bikes and getting set to try a 4" tire and 170mm dropouts 100mm BB, and I'm thinking about the bends. So far the Deda 29r+ and big dimples from a trailer ball hitch are enough, but keeping the CS against a smooth support is what I'm worried about when I have to bend more.

    What are you planning for CS bending?

    The ameriflame 71 handle is nice for me
    Ameriflame MD71TH 6-Inch Light Duty Welding Handle for General Purpose Heating, Brazing, Welding and Other Flame Processes - Amazon.com

    cheers
    andy walker
    andywalker.info

  4. #4
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    Quote Originally Posted by Meriwether View Post
    What was your process you followed for brazing it up? Did you tack it up in the fixture or did you follow Paterek's method of brazing in subassemblies? What does your frame fixture look like?
    My frame jig can be seen here. It's a copy of the instructable 8020 version made out of 1020 profile extrusion with some slight variations.

    I used my jig to tack/thin my tubes together in place and then take them out to braze the fillet. I did however follow the Paterek sub assembly sequence. Having no flat surface, I used my jig as a "checking" fixture to see if my final sub assemblies and frame stayed at the desired angle/position. It's definitively not high precision, but probably close enough.

    One thing I did not do enough is braze a little, check angle on drawing, braze some more, check angle again, braze, check... The book clearly emphasizes on this but I got carried away and brazed all around in one go. Not having 100% heat management and perfect miters under control, my DT/HT angle got off a little after brazing.

  5. #5
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    Quote Originally Posted by afwalker View Post
    Good job so far.... What are you planning for CS bending?
    Thanks! I plan on making some wood mandrels and some king of pivoting craddles to hold the tube. Something like this or variations of it. Lots of good info in this thread

    I will be trying the "filled with frozen soapy water" trick to minimize my chances of collapsing/kinking the tube. (unless someone strongly advises againts it for some reason?) I know it not necessary with a proper bending set up but I suspect my initial trial might not be perfect. I live in winter wonderland so freezing it should not be an issue for the next couple of months!

    Quote Originally Posted by afwalker View Post
    The ameriflame 71 handle is nice for me
    I really started as a total noob regarding O/A set up. So I went to the auto part store and bought everything all at once. This way, I was sure it was going to fit together. Plus I really wanted to get cracking at brazing practice.

    Looking back, I should have researched more and also go to a welding shop so I could have good/better advises and help. The big torch works OK, but it lacks in precision and ergonimic. I also mess up the O/A mixture sometimes because the knobs hit my forearm.

  6. #6
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    Sweet to see my old posts in that thread, but its a good talk about seat stays.
    I still don't have chain stays figured out.
    I've made some wooden cradles and have a 2 ton press that I use that 2" trailer ball to make big dimples, but it's pretty hard to get oval chain stays bent since it's hard to follow the bend and stay tight with a die or mandrel.
    Most folks I guess use round tubes for CSs if they're doing big bends.
    So far for me, my biggest hurdle in doing a 4" fat bike is the chainstay.
    The Anvil bender is great for the seatstay.
    Whit may chime in if he's done 4" tires, I know he's done Knards.
    cheers
    andy walker

  7. #7
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    Chris from 44bikes does a nice job with his round chainstays,
    Clean Procedures 44 Bikes
    cheers
    andy walker

  8. #8
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    hhmm! So it sounds like I might have over simplified my approach to bending CS. I figured it was just and "oval seat stay" so it *should* not be that much harder to bend. Sounds like I in for a challenge! I will definitively report back when I start trying; regardless of the end result (failure or success).

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