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  1. #76
    J_K
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    I finally have my "homemade" frame jig in use. Basic design is from Kris from 44 Bikes, I made some modifications to make it suitable for my budget. Once funds allow I will make some upgrades.




  2. #77
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    Quote Originally Posted by TrailMaker View Post
    - JIG drawing. Frame rotated with HT vertical and pertinent hard points measured from
    there.
    All the fixtures are set in the beam jig using this drawing. This is how it looks in the
    main jig.
    !
    This pretty much sums it up for me. I saw the stick on ruler and thought there may be some advanced geometry or voodoo involved with setting the BB drop and head tube height. I guess this is one of those cases where the simplest answer is the best one.

    thanks!

  3. #78
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    Hi guys.
    I use rattle_CAD and the jig is based on the software output.
    Everything is based on a line through the rear axle rectangular to the top-tube.
    The jig can be rotatet in the roll-stand.

    Setup sequence:
    - headtube height
    - distance seattube to headtube-axle (there is a bolt behind the seattube hollowprofile, sliding it, fasten the screw)
    - seattube angle (angular offset from headtube, hollowprofile rotates around the bolt mentioned above)
    - bbs height (sliding bbs fixture)
    - rear-axle distance to headtube-axle

    Itīs the same schematic as the chris king jig uses.
    Attached Thumbnails Attached Thumbnails your home made jigs-miwi5_26.jpg  

    your home made jigs-miwi5_27.jpg  

    your home made jigs-miwi5_39.jpg  


  4. #79
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    me too,I don't know how 3wfab does his, but on mine, you draw a nice 2d drawing in CAD

  5. #80
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    This may have already been posted, but I will do it again:

    My Almost-a-Jig based on Dr. Welby's design

    To go with the free tubes: some almost jigless tooling

    I am about to dig it out of the rafters and build more frames.
    mtbtires.com
    The trouble with common sense is it is no longer common

  6. #81
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    Quote Originally Posted by 3wfab View Post
    rocking the beam here
    What are the lengths that you use for the extrusions in your beam jig, 3wfab? And for someone looking at building a similar jig would you recommended that length, or go longer/shorter etc.?

  7. #82
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    24 for the vertical and 36 on the horizontal.

    You cannot put an entire frame and have the HT and dropouts fixed at this length. To do that, you would need to increase the horizontal beyond 36.

    For me, it's a non issue. I build my frame in 'sub assemblies' so I don't have the need to put the full frame in a jig.

    Hope this helps-

  8. #83
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    Thats great thanks.

    Time to get building

  9. #84
    The Matt
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    Here is mine. It is long enough to build a long bike on it. I made a long bike 29er with it and I think it is set up for that now.



    PS. It is for sale if you are interested.

    Matt
    mlhoppen(at)gmail(dot)com

  10. #85
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    Jig in work

    So after staying up all night with my newborn son I drafted up my first jig concept and figured I'd post it for any suggestions. Still need some work on the rear axle, but the assumption/hope is to use an anvil dummy axle, or potentially machine my own if I can sort out the lathe access I might have.

    Also, I think i'll beef up the rear axle pieces/braces, just doesn't seem right to me.

    Also - for those out there using the 4337 Angle plate from 8020 for the main tubes, what do you suggest for mounting to the main beam? I'm not sure i really like the current setup with the main pivot bolt and angle clamp being the only thing that keeps those in place, and have seen others that have a seperate plate between the vertical arms and the main beam - I'm assuming thats to allow the post to be moved without adjusting the angle, but curious if there was other motivation as well.

    Anyway, its a start. Plan is to model this up, as well as a Chainstay/seat stay DIY miter Jig I can use in my drill press, then start buying material and building it up.

    I have rough start on a frame, but that needs even more work. Plan on getting that model up to speed soon as I sort out my Jig materials as I'll be waiting around for those.

    One other question for you all - My design has custom cones, as I haven't had much luck sourcing any off the shelf part that could do that job. Is that correct for the most part?

    your home made jigs-slide1.jpgyour home made jigs-slide2.jpg

  11. #86
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    Caught a glimpse of this in a Santa Cruz Bikes video, thought you guys here might appreciate a look-see.

    your home made jigs-santa-cruz-prototyping.jpg
    Bend, OR

  12. #87
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    Quote Originally Posted by MannaDesigns View Post
    ieces/braces, just doesn't seem right to me.

    Also - for those out there using the 4337 Angle plate from 8020 for the main tubes, what do you suggest for mounting to the main beam? I'm not sure i really like the current setup with the main pivot bolt and angle clamp being the only thing that keeps those in place, and have seen others that have a seperate plate between the vertical arms and the main beam - I'm assuming thats to allow the post to be moved without adjusting the angle, but curious if there was other motivation as well.
    You can bolt the adjustable beams directly to main beam with button head allens and t-nuts. Just drill an access hole for your allen wrench for the bottom pivoting point, and a small slot for access to the top bolt. You can keep the pivoting bolt from sliding in the t-slot by blocking it in place with a locking t-nut on each side.

    It's probably worth saying again that the Arctos jig that this style is based on was tricky in that the beams didn't pivot around a point on the mounting plate on the main beam. They actually rode in a pair of parallel arc-shaped slots that allowed the beam to pivot around a virtual pivot point - in the case of the seat beam around the centerline of the bottom bracket.

  13. #88
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    Quote Originally Posted by dr.welby View Post
    You can bolt the adjustable beams directly to main beam with button head allens and t-nuts. Just drill an access hole for your allen wrench for the bottom pivoting point, and a small slot for access to the top bolt. You can keep the pivoting bolt from sliding in the t-slot by blocking it in place with a locking t-nut on each side.

    It's probably worth saying again that the Arctos jig that this style is based on was tricky in that the beams didn't pivot around a point on the mounting plate on the main beam. They actually rode in a pair of parallel arc-shaped slots that allowed the beam to pivot around a virtual pivot point - in the case of the seat beam around the centerline of the bottom bracket.
    Thanks for the input - I hadn't seen that arctos jig, rather I saw a similar arctos copy from 8020 from another forum post... thats REALLY helpful. I'm gonna take another look at the actual arctos jig tonight and see if can't come up with a better way of mounting the main tube supports to pivot around the centers like you mention.

    Also - good call on the locking in place suggestions, I like the ideas.

    Thanks!

  14. #89
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    For the people with jigs using cones, what are your preferences on the material?
    Stainless?
    Steel?
    Aluminium?

    I'm guessing that steel or stainless is better with the heat during tacking. Or is it not too much of an issue?

    Cheers

  15. #90
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    Josh

    I use Steel in mine, but I don't think it makes any difference between Steel or Stainless.

    Eric
    BRAKES...? I'm trying to go FASTER!!!

  16. #91
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    Mine are aluminum and they work just fine. Something harder would be better if you were doing production numbers, but for the garage builder it's good enough.

  17. #92
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    If you can't get cones, trailer hitch balls work very well. I have the ebay cones for my jig, but my first frame in the jig was with a 44mm paragon headtube and the cones were too small. I found that 1 7/8" trailer hitch balls work perfect. I got them for $5 each at the Tractor Supply store. The 1 1/2" balls should work nicely for a 36mm headtube.

  18. #93
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    Thanks for your suggestions. It sounds like you can get away with using any of the three, so I will probably just use whatever is the most easily available. I'll also keep trailer hitch balls in mind, quite a crafty solution!

  19. #94
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    My 1020 home made jig

    My jig as nothing special. It's a copy of the instructable version found here: The simplest bicycle framebuilding jig I could come up with.... The only difference is I've made it out of 1020 extrusion instead of 1530 so I figured I post my comments about that.

    The 1020 extrusion made the jig both cheaper and lighter and I feel it will be strong enough for the light duty frame building that I will be doing with it. I got the cones and "BB seats" machined at a local machine shop and the rest of the drilling and cutting was done with simple tools and paper templates and stock 8020 parts.

    I've yet to complete a full frame with it so my opinion may change but so far so good. First upgrade will be beefier rear wheel and BB axle that are currently made out of 3/8 threaded rods. I'd like to have something stiffer to ensure proper aligment. Some tape measure gluing might also happen to set up faster, but speed is really not important for my purpose. I used some plastic linear bearings to try and improve precision of the adjustments... we'll have to see if they survive the heat from brazing. I plan to only position and tack in the jig and complete the filet outside of the jig.

    Overall dimensions are 48" wide by 39" height. I'll be abel to do some XL 29er on it.

    Some pics
    Attached Thumbnails Attached Thumbnails your home made jigs-p5010003.jpg  

    your home made jigs-p5010002.jpg  

    your home made jigs-p5010004.jpg  

    your home made jigs-p5010006.jpg  

    your home made jigs-p5010007.jpg  

    your home made jigs-p5010010.jpg  


  20. #95
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    Quote Originally Posted by frankzetank View Post
    My jig as nothing special. It's a copy of the instructable version found here: The simplest bicycle framebuilding jig I could come up with.... The only difference is I've made it out of 1020 extrusion instead of 1530 so I figured I post my comments about that.
    Cool! I've been waiting to see someone do some sort of linear bearing type mod to the design.

  21. #96
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    Not exactly "home made" But I just finished my second jig, and unlike the first, this one is straight, rigid and actually kinda nice. A professor of mine helped me build it. He built frames in the 70s and 80s and then moved into precision machining. He was an awesome resource to have and he was generous enough to let my use his shop and a lot of is knowledge.
    It came out really great and I can't wait to start building frames on it.

    your home made jigs-20130513-105207.jpg

    your home made jigs-20130513-105214.jpg

    your home made jigs-20130513-105221.jpg

    your home made jigs-20130513-105228.jpg

    your home made jigs-20130513-105234.jpg

  22. #97
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    Brilliant set-up you have there.
    Two things I like are: angle indicators for the seat tube off the BB and the descent gap to work around the rear side of a frame. I've seen some jigs with too little room in that off-side position, but you need a solid jig back-bone to make it work. Looks like you've received some really good advice.

    Eric
    BRAKES...? I'm trying to go FASTER!!!

  23. #98
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    Very nice. How much machining time for the non 80/20 parts?

    thanks, Brian

  24. #99
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    Hey, thanks Eric! And Calstar, I'm not sure on a specific number, but it took us about
    Five 12 hour days to make. It could have been faster if I knew Gibbs or mastercam better, but it did take a LOT of work.

  25. #100
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    your home made jigs-sam_1416.jpg

    that is all for now

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