Anyone build their own frames?

Discussion in 'General Questions' started by Demosthenese, Mar 27, 2008.

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  1. Demosthenese

    Demosthenese Guest

    hey all,

    i've been interested in building bikes for a while now, and i'd like to move into being able to build my own frames. I've been doing a lot of research, but i would love advice from someone all ready doing it.

    Anyone build frames non-professionaly? If so, what tube bender do you use, and what type of tubing? I will be braze welding, not mig or tig, but that's the only limitation as to what i'm willing to do/learn. I'll probably end up building a jig out of lumber and grabbing a cheap tube miterer from somewhere, since those things seem essential.

    I really want to find a cheapish, manual tube bender for steel tubing.

  2. VincenT

    VincenT New Member

    I haven't built my own frames yet, but I do have plenty of experience with tubing and pipe. I've built safari racks, tube bumpers, exocages, light guards, etc...

    If you're looking for an inexpensive TUBE bender, the jd2 Model 3 bender is the way to go (I have the model 4 electric hydraulic :cool:) I would also go with a tubing roller... saving up for that one... The cheapest tube roller I could find is at can't really beat the look of a nice flowing arc on a bike. suppliers for the tubing bender are, or

    If you are going with tube and using it for a motorized bike I wouldn't go any wall thickness thinner then .90 for ERW or HREW you can probably go with .65 DOM but that would be dependent on gusset and bike design.... remember triangles are your friend.

    If price is a concern... instead of using tube, just go with pipe. You probably already know this, but the difference between tube and pipe is... tube is measured OD and pipe is measured ID, that means 2" pipe is larger then 2" tube... anyways, Harborfreight carries a 12 and 16 ton PIPE bender good for 90 degree bends. You could tweak a 180 degree bend but it will have a larger radius and you will have 3 bend points. Another reason to go with pipe is, its readily available at Home Depot and Lowe's. Harbor Freight also carries a tubing notcher for cheap and a magnetic angle/degree could also use it for Plane of Bend using a C-Clamp...cant remember what it's called.

    You can also use the Harborfreight PIPE bender to bend TUBE....but you will have to pack the tube with sand so it doesn't crease the bend.

    Here's some info for bending tube/pipe...
    and for tube notching and material strength

    sorry for the outside links... let me know if this is a bad thing?????

    Hope this helps...
  3. Demosthenese

    Demosthenese Guest

    thank's a lot man, this is very, very helpful.
    so if i were to use 3/4" schedule 40 steel pipe for most of the frame, and possible a larger downtube, would that be strong enough? assuming proper gusseting, mitering and welding of course.

    Dimension Name Value
    Nominal 0.75"
    OD 1.05"
    ID 0.824"
    Wall 0.113"

    as far as i can see then, the things you need to build a frame out of pipe are; pipe bender, tube notcher, angle grinder, chop saw and welding equipment.
    Last edited by a moderator: Mar 28, 2008
  4. VincenT

    VincenT New Member

    That would be plenty strong enough... but that is just my opinion and design usage of that type of material... others may have different opinions based on their experience.

    Make sure you post pictures and write ups... it's always great seeing how different people approach a project.

    RATRODER Guest

    Last edited by a moderator: Jul 5, 2008
  6. Demosthenese

    Demosthenese Guest

    ok well my first project will most likely not be a bike; to "get my hand in" i'm going to design a motorized trailer. It will have a four stroke mounted in it, and probably a pretty big rear wheel, as well as a pivoting mount attachment. the whole thing will connect to both sides of your rear fork, and i may have to work out some non-bearing pivots or something for that attachment to the rear axle.

    much like that, only i plan to have sides on the trailer to conceal the engine within, and also a platform space in front of the engine, between it and the bike, for cargo.

    should be easy enough, once it's all planned and measured out. I'm probably going to cut a back fork from a bike and use that for the back wheel mount, weld in a long main tube and then use either some cheap bearings or the stearing head from a dead bike to make a pivot ill mount the hitch too. Use triangles+ more tubing to build a strong frame, and then some sheet on top and along the sides. it'll look alot like one of the "bob" tailers.

    i was worried when i first conceived of this that push against a pivoting hitch wouldn't work, but i think that apart from gunning it from a standing start, it'll be ok. no hard accel arround turns i guess? lol. i'm gonna grab some graphing paper and figure out measurements and such. don't want the wheelbase to be too long... not much more then the "bob" units.
  7. DougC

    DougC Guest

    Many people who have tried the cheaper tube miter kits say that the tubemiter.exe program works just as well. This is a small program that you enter the tube angle and thickness in, and it spits out a template that you print out and wrap around the tube and trace, and then cut out with a grinder and hand-file to finish it. If you work slowly and carefully you can get nearly-perfect results for not much money. Just Google it and download it from a reputable source (it's on the IHPVA website somewhere I think).

    The cheaper tube-mitering clamps do not work as great as you might think; I've heard a lot of people say that for the hobbyist, they aren't really worth the bother. They generally have a limited angle range (usually no more than about 30 degrees from perpendicular) but the main problem I've read of is that there's no good saws for them. The saws come in limited diameters and aren't really intended for metal cutting, so they don't last long. In particular, I have read that the bushings in the Harbor freight miter clamp are lousy and replacing them with good bushings nearly doubles the price of the effort.
  8. Mr.G

    Mr.G New Member

    I have built several recumbent frames, I have used mapp gas and 1/8'' brass rod, I have used old 4130 bike frames. Never broken any of course I only weight 160#
  9. Demosthenese

    Demosthenese Guest

    thanks guys, this is really helpful.
    well, since i've read elsewhere about the miter clamp problem too, it does seem like a possible wasted investment. I have access to a drill press all ready, but i could just put the money i would spend on a miter into the angle grinder instead.
    Still seems like i could be building my own frames for between 350-500$, depending on the welding equipment cost, and the quality of the other tools. Seems cheap, considering.
  10. nwguy

    nwguy Guest

    I've done lots of frame hacking in building (weird) bikes and scooters (see ). My own tools of choice are as follows:

    An oxyaceteline setup for brazing, not welding. Brass is easy to work with compared to welding. I like to use brass rods that are precoated with flux, rather than bare rods with paste. If you braze or weld, work in a well ventilated area as flux fumes are poisonous. I bought my first welding setup at a pawn shop for $50 and have since replaced the hobbyist sized bottles with bigger bottles, but still use the original hoses, regulators and torch. Don't be afraid to take a welding class. You'd have fun. Brazing is really fun.

    I like my Harbor Freight tubing notcher. It needed shimming, but it's worked well for me. The hole saws that I bought for mine have worked well for years. Get decent ones. Use cutting oil on them when cutting tubes. Go slow. Wear eye protection.

    You need a drill press for the tubing notcher, but you need one for other stuff anyway. They're all made in Taiwan now pretty much, so take your pick.

    You should collect as many files as you can. Collect different profiles (flat, half round, round, triangle, etc.), different grades (course, medium and fine) and different sizes. I use golf balls for file handles. Learn to file. It's an art. Files like hacksaws only work in one direction.

    Collect clamps too. C clamps and bar clamps. Go to yard sales for this stuff when you can.

    Get a decent bench grinder, and the stones to clean up the wheels with after heavy use. Use it to remove lots of metal fast. Watch your fingers and hands.

    An angle grinder is extremely handy. Cleans scale off of metal before brazing really quickly. My $17 jobber from Harbor Freight works great, but is really noisy.

    A belt sander is super handy for removing paint from tubing before brazing or welding it. Also handy for making cuts at the ends of tubes square, as it grinds metal to an extent. You can press a piece of tubing against the right angle guard/brace piece, then down onto the moving belt to get the square end. Rotate round tubes when you do this and you'll get a squared off end. It wears the belts quickly though. I usually file most of the paint off used tubes first, then hit it with the belt sander.

    I'm more of a fan of reciprocating saws with metal blades than chop saws. My Makita can get in tight places and can cut pretty thick metal with a decent blade. Buy blades in bulk, they're cheaper that way.

    Make or acquire a big, sturdy, smooth, flat and level bench. I built a sturdy one out of wood, then fastened two sheets of cement backer board onto it with screws for heat protection, then screwed down a big, 3/16" piece of plate metal I bought at a salvage yard. I braze, weld, and hammer on this thing. It's great.

    I got a Drill Doctor for xmas a while back and am still trying to determine if it does a decent job or not. I have friends that sharpen bits by hand on a grinder. I've tried that but haven't developed the touch yet.

    On tubing, collect old bikes for tubing. They're free all over the place if you're patient. If you resort to using electric conduit tubing like I do at times for odd stuff, file or grind the zinc coating off before applying heat. The zinc coating is poisonous.

    More later if I think of it.
  11. graucho

    graucho Active Member

    Not a pro at bike frames, mostly have done mini choppers. I purcheasd some bender plans cheap from ebay. They say you can build in a few hrs, took me a saturday.

    Also got rid of my torches and arc welder years ago when I stopped building street rods.. Purchaced 110v mig from ebay also to do the thin stuff. Took some practice, works great on frames.

    Attached Files:

    Last edited: Apr 9, 2008
  12. lennyharp

    lennyharp Member

    I use 4130 Cro Moly Seamless tubing if possible for my bike frames and trailers. The frame work I built to handle the Staton gearbox and EHO35 Subaru motor is .049 wall thickness 1/2 inch tubing I got from Tube Service downtown Phoenix. I have bought from Nova Cycle Supply and the tube sets are great if you want to build a complete frame. They have bottom brackets, braze ons, head tubes, drop outs and all the fittings needed as well as many tubings. Probably need at least the Mountain bike or tandem tubes as road bike stuff is so thin it would not hold up to motored bike use. Here are some tables with common bicycle steel sizes for 4130 .......
  13. SimpleSimon

    SimpleSimon Active Member

    Great thread. I have been working on and tweaking a bicycle design for most of a year, after spending more than 6 months learning the basics of steering geometry, ergonomic design as applied to bicycles, etc. Practical design work has been frustrating at times, but very interesting, and the info here will be a very real help. Thanks to all of the contributors to this thread.
  14. lennyharp

    lennyharp Member

    I find the geometry a facinating part of the design process. Seems there are a lot of ways to look at what is desired. I look at the motored bike as a performance bike that needs performance built into the frame angles. The frame I think can be longer than a racing bike but it probably needs angles a lot like the racing bikes. I am going to extend a frame to have about 15 extra inches in the rear end from bottom bracket to rear hub. I will probably just cut off the rear end and rebuild it to my specs.

    I will use the angles that a racing mountain bike use as it is designed to go 50 miles an hour down trails and keep control easy for a tired racer. I am using a racing frame right now and find it works great. I will be shooting for head angle 72% seat tube angle 72-73% bb heights 11.5-12 inches chain stay length about 32 inches. There are lots of measurments and angles to take into consideration, shows a specs sheet for their bike. This is not a race length but the angles are straight from racing bikes. All I can do is try and see if my theories work out.

    Augidog is using this stretched out frame design, but I don't know any measurements or angles he used. I started building frames in the 1980s when mountain bike design developed. The changes that took place and interesting geometries used was an education for me.
    Last edited: Jul 5, 2008
  15. SimpleSimon

    SimpleSimon Active Member

    Well, rats.

    I had a long post finished, hit submit, and it evaporated.

    I'm not going to re-write it. Suffice it to say, I need a trike. I want a tadpole for various reasons, and I want it to be a leaner for those same reasons. Semi-recumbent I need. Nobody I can find builds one, except some of the forward spar mounted crank recumbents, which for various reasons don't work for me, and they are all ****ably expensive.

    So, I've designed one. I'm about ready to begin building it, which means I need to find shop space I can use (at least a garage), and I need to do so soon. Money is the biggest limiter - disability income doesn't go far. Material costs will run about $700, depends on how much I can salvage.
  16. fm2200

    fm2200 Member

    my experience with welding and fabricating a frame for motorized bikes was ok but they were weren't works of art, kind of utility looking. Now in my opinion you'd be hard pressed to make a better looking frame than what's out there now like the Schwinn old style frames the kind China's reproducing for these gas bikes like the one's sold by spookytooth cycles. I have an all chrome frame and you could never afford to chrome plate a frame after fabricating one, and to make a better looking frame is doubt full. Unless of course you think, you are the a legendary designer with a flair for artistic ability and innovated one of a kind concept, then you just may pull it off. For me I'm really satisfied with the old style Schwinn that I have from spookytooth.