building a frame (literally)

Stickler · Dec 19, 2006

You can't weld aluminum and steel/chromoly together.....different types of metal don't mix.

Kornphlake · Dec 19, 2006

There are many reasons you can't do many things you asked about.

I don't mean to discourage you but you're not likely to be able to design much less build a frame if you're asking such basic questions like these. Hang out with your buddy while he is building his trophy trucks and ask questions about the trucks and what he's doing with the equipment. Sooner or later you'll figure out how it might apply to building a bike. If your school offers any shop classes take those, if they don't offer classes take a look at the local community college, most offer introductory courses on welding.

coma13 · Dec 19, 2006

no, you can't weld aluminum to steel.

why would you want a triple-walled bottom bracket shell? how would you even do that?

have you actually drafted our your linkage design and figured if it could work?

i'm not saying not to do it, because home-made stuff is cool as hell but do your homework first, figure out the problems before you've spent a ton of time and money making something that won't work...

MrPlow · Dec 19, 2006

By the sounds of it I think your better off buying a frame.

iridebikes · Dec 19, 2006

I've built several frames. I'm in the process of making 4 frames. one hardtail 2 dual suspension 4x bikes and 1 dual suspension dh bike.

Building a frame isn't that hard, you just need to know what you're doing, know the steps, and know what not to do. You also need to know what kind of tubing to buy, what's too thin, what's flexy, what's strong, what's a bad design. There's a bit of brains that's needed to be able to build a frame well.

I'm also planning on building myself a 3 pound dual slalom specific frame for this next season, a 2.75lb track frame for this next track season, and a cross frame for next year's cross season.

Knight Cycles for the win!

If you have any specific questions about building frames pm me.

Thrillkil · Dec 19, 2006

cheetaprowlerDH said:
has anyone ever handbuilt their own custom frame?
i have hundreds of linkage designs that i have thought up on my own and i want to actually go out and build one.

is it hard to do any of this?
i doubt i will have many problems due to the fact that i will be building with a friend of mine who handbuilds Baja trophy trucks in his shop... but i was wondering if there are any other major things to consider other than measurements of the Head tube and BB shell.

oh yeah, is it possible to weld chromoly to solid aluminum??? is there some kind of difference in the welding of each metal? i want a chromoly frame but at the same time, i want to have a solid 2 peice aluminum BB block with a triple walled chromoly BB shell (for many reasons).
we have a CNC machine, chromoly tubing, solid aluminum blocks, and everything we need to build it, i just want to troubleshoot first.

thanks

why haven't you just bought that disco yet?

Thrillkil · Dec 19, 2006

cheetaprowlerDH said:
aaaaahhhh dont remind me!!!

afromandookie · Dec 19, 2006

not to butt in but how can u properly measure travel in the rear on a built up bike

dcamp29 · Dec 19, 2006

do a search-

edit:
here:

http://www.ridemonkey.com/forums/showthread.php?t=143840&highlight=4130

http://www.ridemonkey.com/forums/showthread.php?t=171355&highlight=home+made+bike

http://www.ridemonkey.com/forums/showthread.php?t=169083&highlight=4130

mattmatt86 · Dec 19, 2006

I made a Hardtail in my HS welding class. It was an aluminum dual slalom frame, 15", 68 degree headtube angle with a psylo race on it, 16 inch chainstays, gussets everywhere. I got it powdercoated saftey blue, and had about 1500 in parts on it, then it got stolen my first semester at Clemson.

Urwin · Dec 19, 2006

use linkage, tells you the travel, axle path, chain extension, etc

Kornphlake · Dec 20, 2006

cheetaprowlerDH said:
he taught me how to machine with his program (i cant remember what its called), and i've used a program of his (again, i cant remember what it was called but i know that it was some sort of CAD) to test the strength of SOME of the frames i've designed and so far, 3/5 of them have withstood around 5g's and a few thousand pounds of pressure around the head tube, BB block, and swing arm (this being with every place where there would be a pivot is fixed because i dont know how to configure a shock and leverage and travel ratios into the program). again, i dont know what it would withstand in real life because this was done on a program's estimate.

he said that if we do end up building it, he will teach me how to weld, but for the first frame, he will do it all while i learn to weld different pipes together in different angles. (he literally does a nicer looking weld than Nicolai)

See this is what I'm talking about, you can't remember what its called but you did something with some machine and it looked sweet.

How am I supposed to help you when you don't even have a basic understanding of the principles you are working with? If you want to build something by all means build it, if you want to engineer a frame you need to learn to communicate appropriately. Part of that would be learning the lingo (IE what program, what kind of process, what grade of steel, what are the actual dimensions etc.) It sounds like you are just trying to build something because you know where you can get free materials and labor, which is fine and dandy but I'd consider this first project to be a piece of art rather than something you will be able to ride, unless of course your friend really knows alot about bikes and is going to guide you in the process.

blue · Dec 20, 2006

Listen to Kornphlake.

This isn't like going out and building a treehouse with your buds. Draft your stuff up in a CAD program, find the right tubing, etc. You can't just start mashing tubing together and hope it will turn into a DH frame. How old are you, 15? I'm sure your HS has some form of basic drafting class that you can take that can teach you what you'll need to know. Take welding/machine shop next year and show up with a work of art DH frame to awe your teacher. Win!

You've got the resources, you just need the know-how.

RaID · Dec 20, 2006

to add to what the above 2 have said

maybe you should start building a HT frame first before moving on the complexities of a FS frame.

do you have any ideas about:
pivot placement?
chain growth?
shock rates?
the geometry you want?
wheel paths?
whats sort of ride characteristics you want and how the above things
alter those characteristics?

iridebikes · Dec 20, 2006

maybe you should start building a HT frame first before moving on the complexities of a FS frame.

I highly suggest that as well!!!

Trust me, from experience, it's much easier to make a hardtail than a dually. I'm not saying it'll be easy, but it's less complicated. And if you seriously are thinking about building a dually bike, start off with a single pivot frame. it's much easier, You have one pivot and one shock mount rather than a bunch of pivots that you need to get perfectly lined up with the rest of the frame and level. Without a proper jig it's EXTREMELY hard to do! It's doable mind you, but extremely hard

boostindoubles · Dec 20, 2006

definitly try a hardtail first

OGDMFG · Dec 20, 2006

the best advice is try to design up something that you think it will work, then put it away for a say a month then look at it again, believe it or not you will see some things that you missed, then put into the linkage program, if it still looks like what you want proceed, always look at the project with some objectivity, your first bike will open your eyes into what is really important in frame building, Oh by the way i hope you like solving problems. I have built 15 dh frames, I jumped in the deep end of the pool so to speak.

good luck
OGD manufacuring

OGDMFG · Dec 20, 2006

You can purchase the linkage off the web,do a search it is under bike linkage, should be under bikechecker.com cost is 25 bucks for the personal edition, I check all my designs with this programs.

beaverbiker · Dec 20, 2006

instead of calling the tubing thicknes triple wall, you should specify how thick it is. triple wall tells us NOTHING.

if you want tubing for cheap checkout aircraft spruce in corona, ca. you can get any size you want and it's pretty cheap and fast if you live in the US. you don't want to build the whole frame with 2" diameter tubing.

if you've only been around bikes for a year and a half, i have a hard time believing that you know exactly how different linkage systems effect every aspect of the ride characteristics. misplacing a pivot point by a very small amount can ruin a design. dont get me wrong, i'm all about people building stuff, but like everyone else, i think you're in over your head.

i wouldn't even begin to make a full susp. frame without having a 3D model of it first. and when you're building your model, be sure to keep in mind what your manufacturing capabilities are, i.e. don't model crazy extruded tubings and such.

good luck dude

jet · Dec 21, 2006

Triplle wall tubing is rolled three times-three layers. Not tripple butted, three thicknesses. If you make a 'mock up' type frame it (an fs) would probably weigh about 15lbs.;without shock. Maybe more.
You could probably join steel to aluminum, you just need to bond it with some sort of aerospace bonding/epoxy agent, like carbon fiber. But you can't weld them. Steel takes a pos to neg polarity and AL. takes neg to pos polarity.
I've been thinking about making some frames now that I ve got back into welding. Using my companies steel suplier to get some tubing and whatnot. Catch is We use stainless and the frames would be really heavy, even ht's. But it would be a good place to start.
I've got some designs in my head for some FS's - but where could I get linkages and pivots? That's my stumbling block. You can order dropouts and whatnot from the internet, but who makes pivots out of steel? Before I make something out of aluminum I want to do it in steel first.
There is a machine shop moving in across the highway from me though...They make some really sweet air cleaner covers for choppers. Really cool CNC stuff. I called them for an interview a few months ago and one of the owners I talked to was really interested in getting into bikes.
TIG welding isn't really that hard, it just takes a lot of practice. Put it this way - you will get very good at sharpening tungsten. The hardest part is keeping the filler rod off of the tungsten. Since you have to use your non-dominant hand, you will stick the tungsten a lot.. It really is an art form. If you are kind of artistic, it may come kind of easy. It helps to be a bit ambidextrious. The foot pedal is one of the keys also. Think of it as a 'gas' pedal. Don't just nail it and go. The pedal controls the amp's. The more you press the hotter the arc. Practice on some flat pieces first. Don't try doing tubes first. You will need to learn how to drag (float) your hand that has the torch across the metal. Tubes take a different style. You need to rest your torch hand on the ball of your palm and rotate the torch. The hard part about this is you need to keep the arc pointed in the right position. So your hand is moving in one direction and your fingers need to guide the arc in a more precise direction. PLUS you need to get the filler wire in with your other hand.
But I'm sure your freind can help you with all of this.

thaflyinfatman · Dec 21, 2006

cheetaprowlerDH said:
i was talking to him yesterday about it and he said that he has built around 10 BMX bikes that have never broken, and one single pivot dually that has yet to break, and he is up to teaming up with me to take on this challenge.... except that the frame will be a boat anchor because unless i want to pay to ship lighter tubing over, all we have to build it with is the 2" triplewalled 4130

i dont know the lingo yet, i have heard it for sure by hanging around his shop and watching him build the JB motorsports baja truck from the ground up, and i am sure that i will learn most of it after only around a day... so be patient, i will soon be able to talk amongst you manufacturers.

You reckon you're gonna "learn most of it after only around a day"? Dude... you have NO idea how complex it is to design and build stuff like that. Sketching out random linkage arrangements on paper is absolutely NOTHING, in fact, unless you've got it all measured up and the linkage is fulfilling whatever criteria you set (axle path, shock rate, braking characteristics, whatever) then you're not "designing" anything.

I hate to break it to you but at this point in time you've got no hope of making something half-decent. I'd highly advise you spend a LOT more time considering this stuff and learning all the relevant stuff you can find.

ÃX · Dec 21, 2006

look what you have done now david!

iridebikes · Dec 21, 2006

all we have to build it with is the 2" triplewalled 4130

Tubing diameter is too big, and i'm guessing the wall thickness is way too thick as well. I use .035" tubing with absolutly no problems. it's a little on the heavy side(8 pound 4x frame), but the dual suspension bikes I'm building will be thrashed so I don't want any of them to fail.

I'm goign with 1.5" down tube, 1 3/8 and 1 1/4 tubing for the tup tube (gemini style front triangle) 31.8mm seattube(lets you run a 30.0 seatpost). You could run a 30.0 seatube which gives you a 27.7 seatpost.

Check out Henryjames.com Novacycles.com and Aircraftspruce.com for tubing. It's cheap, they have all the braze on's you'll need, BB shells. butted tubing, straight gauge tubing.

As for tools, you can do all the tube mitering by hand(that's what I do and it takes about 4 hours to do a full frame. you'll need some sort of jig. You'll need a mill of sorts for the pivots. I highly suggest against a drill press because they're so lightweight that they jump around and can ruin a completed frame if you're drilling for your pivots.

for finish work you'll need a seatube reamer, headtube reamer and facer, and a BB face and chase tool. Right there is about $1200 worth of tools.

But like it's been said already. Drawing linkages up on paper is one thing. Getting them to work and not look like crap is another. If you're honestly thinking about building a frame do not start with a linkage bike. Start with a hardtail, move on to a single pivot frame and go from there. You mentioned that it won't be the right suspension rate that you're wanting. big deal. That's so amazingly complex that there are even companies who are making production bikes that don't even have it right yet.

I just think you're getting way in over your head without even knowing it.

Maybe try and find some digital cad programs or something where you could design links, design front triangle and design rear triangle and see how it all works together. That would most likely be your best bet on figuring this all out.

You also have to take into consideration stiffness of the frame. You have the ability to make a inovative suspension design. But if the frame is heavy or if the frame is flexy, You've created a wet noodle that you'll hate to ride.

I hope it's not coming across like we're trying to shoot down you're dream, we just don't think you know how complicated it is to build a frame that will turn out ridable. So if you're going to do it, do it right. Take smaller steps towards a complete linkage DH frame.

Homey · Dec 21, 2006

Build a jig, get the right tubing, and go for it. 2" Tripple Wall Tubing is not the right choice. I'm sure your boss will let you order the propper tubing through your supplier. Sounds like you need to spend some time listening in the shop and taking notes...learn the language and use it!
Good luck and have fun! Show us your progress too.

dcamp29 · Dec 21, 2006

bcd said:
look what you have done now david!

oster_oops:

amateur · Dec 22, 2006

Go ahead and post up the design. With all the minds like Weagle's out there, there's probably a good reason you don't see your design in production. On to the fab.

Now you're talking about coming up with a new design, numbers, and machining all new linkage plates if I understand correctly. I'm not sure understand the need for precision to make not only a lasting bike, but one that works well...believe me, there's a difference. Not breaking doesn't mean a whole lot on its own. As for the 2" thick BB shell...

My advice:
Sit back, read up, learn as much as you possibly can. Start throwing your parts in CAD or SW and try not to get lost in computer land. Unless you're building an overbuilt boat anchor of a bike, you're going to be spending a pretty penny on materials alone. Now, coming from someone who has built chassis jigs for 1 cars and a few screw around bikes, jigs are important. Building the frame is the easy part.

Should you decide to sink time and money into what looks like a pipe dream, these links might help.

mcmaster-carr.com
aircraftspruce.com

Engineer to Win by Caroll Smith is about auto racing, but it will certainly help you grasp what you're doing.

jet · Dec 22, 2006

I don't quite understand why everyone is pointing out all the bad stuff about this?
The guy wants to try to build a bike from scratch. I want to build a bike from scratch. Who cares what program it is and if the guy can't remeber what it was. Who cares what size tubing it is. Who cares if the tubing is completely wrong?
Didn't everyone think that Cannondales were stupid becuase they used over sized tubing to gain strength over weight? look at them now.
Give the guy some pointers or advice.

It's not like he's selling them to you or anyone else. Maybe; just maybe, he's got the next big idea. I know that when I saw the new Felt Equilink bikes; I was like, DOH! Why didn't I think of that.

building a frame (literally)

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