DaleG85

Hi guys,
I've recently thought about building my own track/fixie frame for a little fun.

My metal skills will be fine, my bike knowledge may lack a little.

I currently have a carbon track frame that I race and train on. I want to build a track frame that I can have as a loaner for friends or put a brake on it and use it as a fixie. So I'm going to steal the geometry from that.

Tubing will be columbus track kit style unless I choose to change the TT and DT to a larger areo style tube. And I want to run a carbon fork.

Does anyone have suggestions to things I should consider?

Cheers Dale

unterhausen

That's too open ended of a question, sorry.

What resources do you have available to you?

DaleG85

Resources as in fabrication resources?

MIG, TIG, oxy, plasma, lazer cutters, cnc and manual mills and lathes, edm machines, 3d metal printers, soon to be small foundry, you name it I have access to it...

Ok I'll change the question, If you were starting out again... what do you know now, you wished you knew then?

Cheers Dale

unterhausen

One thing I know now is there is always something that I am reluctant to do for some reason and that holds up progress. I now put the most emphasis on whatever that is and get it done.

What issues are confusing to you? What joining process do you think you will use for this first frame? How do you think you will miter the tubes? Tapered headtube? Have you picked out all the small parts?

unterhausen

Just to be more clear, your revised question is too vague. I have learned a lot of things that probably wouldn't make sense to you at your level of experience. So what specifically is keeping you from starting to build a frame? Are you planning on building fixturing first?

Although, the one thing that I have learned is that you should plan on cutting up and throwing the first one away. Boeing did it with the first 717, and that's millions of $ going to scrap.

Nessism

There is a lot of information on how to build frames available on the internet these days. Youtube, the archives here and on various other bicycle forums, pro builders photo archives, etc. A reasonably industrious person using google should be able to uncover enough information to keep themselves learning for weeks in preparation of building their first frame. In my opinion having a proper flat surface to measure and straighten against trump's a building fixture, but in a perfect world you would have both.

unterhausen

there was recently a question on the framebuilders email list about why a frame built in a fixture was poorly aligned. I think the most likely answer was the accuracy of the miters, particularly on a welded or fillet brazed frame. And also, it should be noted that the bb shell faces distort a lot, so they aren't a great reference to check alignment. The head tube is superior if the ends of the head tube are straight.

DaleG85

Thanks for your reply...

For joining I am going to fillet braise. TIG would be my next preferred option because of its added strength.

The mitres will be done probably on the mill, with some final tweaking if required by hand.

I like the look of a tapered head tube so that's what I was hoping to use.

I guess the issues I'm facing so far are:
1. You asked in your question "have you picked out all your small parts?" I haven't picked much yet or brought anything. But what parts do i need to consider before starting.
2. Would you suggest buying all my components first?
2. Is the BB offset towards the non-drive side to allow for the chainring? Or is that taken care of in the design of the crank?

These are probably some really silly questions.

Andrew R Stewart 

A few comments-

Don't assume TIG is stronger then fillet or lugged. Different HAZ location, yes.
With a tapered head tube you will be "tweaking" the lower head miter.
1. All the parts that are needed to complete your frame and to interface it with the components are what's needed. Ideally before you cut a tube.
2. Yes
2. Most all frames are built symetrically, side to side. Most all components that are manufactured are based on this. As you enter the ends of the bell curve in design/intended use this can fall off (recumbents, cargo bikes and extreme MtB bikes)

Silly questions, not really but indicating a lack of bike design understanding. Given this I suggest being willing to mock up situations, have all the parts on hand and spend some time understanding bike mechanics in general before cutting tubes. Andy

Nessism

I'd TIG over fillet brazing, assuming you know how to do both. TIG is lighter, will distress the tubes less, and is much easier to finish.

DaleG85

Thanks guys

Doug Fattic 

I count 6 general steps in building a frame starting with 1st creating the design. This process includes matching the tubes to your bicycle position and the type of riding you will be doing. A lot of beginners make a full-scale drawing, some use CAD and I use my laser cut and etched fixture that is in reality like a full-scale drawing.

2nd the materials are chosen that maches your design. Some choices make your job easier and depends on how much fixturing you buy or make. For example choosing a lugged bottom bracket shell makes it much easier to get the chainstays the exact length so your rear wheel is centered.

3rd you prep the materials and miter the tubes so they all fit together and match your design. Most beginners miter by hand with files because it is cheaper and faster but I like the absolute precision of a machine miter. You probably could build a frame in the time it takes to set up a Bridgeport to do the job properly.

4th you braze or tig the frame together while during the process you choose a sequence and perform checks that keeps the frame in alignment. Most commonly you do this with the help of a flat surface of some kind. A common way to tack the frame together is to use blocks holding the tubes on your full-scale drawing.

Whether you tig or braze depends on your competency. Tig welding thin steel tubing requires great hand eye coordination. If you aren’t good at tig welding now, I would not use that method building a first frame.

5th do the finish filing to improve its appearance and add bridging and braze-ons. And 6th paint the frame.

Just as fair warning, I’ve been teaching framebuilding classes since 1976 and it is a rare student that doesn’t need a lot of assistance to get things right. It is easy to make big mistakes. Among those students are many that have already taken a class somewhere else or have built frames before on their own. Of course my standard is quality and not just good enough.

DaleG85

Great response thank you...

Doug Fattic 

I would assume that the 1st things you will want to do is figure out a way to hold your tubes to your design and have some method to check that they are all in the same plane. Do you have some kind of flat surface at work? For those without access to such goodness they find a piece of kitchen countertop or even a couple of sheets of MDF board put together. A large table saw top can do the job too. A common way to hold the tubes on top of a full scale drawing is with Paragon Machine Works aluminum tubing blocks. There are many different ways to successfully build a frame and we might be curious how you plan to proceed because not all of them work equally well. Some of your methods will be based on what tooling and equipment you have available.

DaleG85

Thanks Doug,

I do have surface tables both at home and work so that bit is easy.

Now holding the tubes I haven't worked out yet. I want something decent, but I don't want to spend as much time building a jig if this is the only frame I'm going to build.

I do have access to some 8040 profile all the jigs are made from.

I'm not sure if anyone has some suggestions for a simple but reliable jig?

wsteve464

If you use lugs and silver braze it you could build a frame without a jig, you have surface tables, get some Paragon tubing blocks a dial indicator and once aligned drill the lugs/tubing and pin it.

Otherwise the 8040 jig is about the cheapest decent option. If you continue to build frames make a copy of an Anvil jig

Doug Fattic 

A flat surface is the best and most accurate tool to build a frame. Like Steve said, since you might not build another frame it makes the most sense to use that as the base for holding your frame. The simplest way for most builders without a mill and/or lathe is to buy aluminum tubing blocks from Paragon Machine Works for $15/20 each and lay them on top of your drawing on your flat table. In some sequence you spot braze the tubes together and check that the frame is still in alignment (and adjust as necessary) and finish brazing free in your bench vise or Park stand. For the greatest accuracy that is a back and forth process.

Of course as an alternative you can attach tube holding blocks to some kind of 80/20 fixture. The problem is that 80/20 is not as accurate as your flat table so what’s the point? Often hobbyists don’t have access to a flat table so the fixture becomes the alignment reference. The purpose of a fixture is to increase accuracy and setup time and look cool to admiring visitors. It is not something to do a full braze in because it restricts moving the frame to the most advantageous position while brazing.

One of framebuilders most basic but necessary tools are wood blocks to hold the frame in your bench vise. Wood blocks have the advantage of having the right amount of holding vs movement ability. The Bicycle Academy in the UK sells them. I have a set for sale too. Sometimes an amateur will use the aluminum Paragon blocks instead. Those Paragon blocks are also useful when either machine or hand mitering. You will have to decide if it is better to spend your time making blocks or your money buying them.

You will get a variety of suggestions on methods to make your frame. For example some builders like to pin a frame before brazing to help hold it together and keep it in alignment when brazing. It is a successful method and the way I learned but isn’t how I do it now. You’ll have to figure out what might work best for you.