Second to last day of class. The pace was been turned up to 11.
It’s quite tiring, but very rewarding.
Here is how I started my Thursday, shaping steel tubes for my seat stays, the connection between the rear axle area to the upper part of the frame just below the seat. Hence the name seat stay.
Since I’m building with lugs, I wanted to make these stays similar to the ones that I had on my very first road racing bike that I bought back in the ’80’s.
That’s the making of the left (non-drive side) seat stay. The right side is a mirror image.
At left is the tubing to make up the seat stay. I filed and shaped it Wednesday afternoon. The piece next to it is a piece of a larger tube that will fit the curve that I wanted. In the middle, the curved piece is brazed to the tube. At right is the finished stay, being dry-fit to the seat tube lug. A few minutes later it was brazed to the seat tube lug, making the connection permanent.
Making these was zen-like. Almost blissful.
By the end of Thursday, the frame was 95% finished. Today is dedicated to the finishing touches, at least as far building goes. Custom fitting the front brake stays, putting in bosses to mount the water bottles and bag racks, trimming the head and seat tubes and starting the long process of putting the finishing touches on the brazes before I send it to a painter. I’m looking at another 15-20 hours of detail work to file and sand the silver away so that the seams look seamless once the paint is applied.
This bike has been fighting me every step of the way. One step forward, two steps back. But we’ll get there.
Honestly, I’d rather have it fight me instead of it being smooth sailing. That way I can get a feel for what really needs to be done at each step.
Here it is, basking in the morning light on my desk, ready to be put in the jig and brazed together. Or so we thought.
Seven hours later it finally happened.
Although everything fit smoothly at this stage and lined up with all of the dimensions and angles of my full scale drawing, once the jig was set up with the exact same dimensions and the lugs and tubes were in place, very little lined up the way it should have.
This was taken right after I had to cold set the bottom bracket, the round fixture at bottom center where the spindle between cranks and pedals pass. Cold setting sounds glamorous (does it?), but it meant nothing more than me placing one tube against my chest and pulling the other tube tightly towards my chest. That helped close the angle between the tubes, as well as open up the connections a bit more so that the silver used in the brazing process would be able to completely surround the tubes.
Right now the main triangle is in the jig. It is now irreversibly joined at the five joints. I completed the brazing at the end of the day, with just enough time to close of the tanks for the oxy-acetelyne torch, complete a safety check and have the instructors lock the door behind me.
They sure are a patient crew. One, a custom bike builder for 40 years, the other a structural engineer with close to a decade of experience. Plenty of brains spending hours stumped at how stubborn this bike has been.
To the left are the chain stays, which will be connected tomorrow, as will the seat stays, which will complete the rear triangle. At that point it will be a bike frame. After that, it’s a couple of days of finish work to make it a rideable bicycle.
That is, once I’m done with all of the other frame prep work and cleaning to get it ready for paint.
I’ve been thinking of a custom label to put under the clear coat once it has been painted. Different options.
No new exciting pictures today, just a catch up on bike school.
This week I started a frame building class, which covers everything from designing bicycles of different types to building them by hand. Since this class has no requirement for previous knowledge or skill (thankfully), we are starting with the basics.
The technique we are using is brazing, which means that we are joining metal (in our case steel) with a dissimilar metal. Depending on the joint that we are creating, our dissimilar metal is either a silver alloy or bronze. Those require us to work at either just below or above 1500 degrees Fahrenheit, dependent on whether we are using silver or bronze.
Here is a fairly typical joining of the head tube of a bicycle and the top tube. The head tube is where the fork runs through to connect to the handlebars and the top tube is the tallest tube on the bicycle, the one that you have to throw your leg over in order to get on the bicycle. I’m using a lug, which helps hold the tubes in place and establish their relationship to each other, in this case 73 degrees.
Although it doesn’t look like it, that’s silver allow that is connecting the tubes to the lug. It’s a bit of a messy job, but considering it’s the very first time I’ve ever done that, it really wouldn’t take but 20 minutes to clean it up to the point that you wouldn’t even realize it was there under the coat of pain that is required for steel.
But while it looks fine from the outside, we are concerned about the connections inside, beneath the lug and between the tubes. And there’s only one way to check the quality of the connections.
Cut it apart.
You can see the discoloration of the steel from the heat and mostly the flux used to etch the steel during the process. But the part that we were concerned about is where the tubes are joined. And not a single gap to be found, so the silver is in contact with all of the lug and all of the tubes. You won’t find that on most mass produced bicycles.
In other words, the tube would shear apart before this connection would tear apart.
Not too shabby for my first time.
A few more exercises like this and in just nine days, save for a paint job and component installation, I will have a rideable bicycle. One that I built myself.
Full disclosure: I have posted this pic in other media, so if you are seeing this again, I do apologize.
This past week was the final week of the full complement of mechanic’s courses at the Bike School. It consisted of two days of wheel building, then three days of suspension.
I had no experience with either, other than the fact that I use the wheels and shocks on my mountain bike, a bike that rarely sees dirt, much less a mountain.
On Tuesday, after a day of very focused training on bicycle wheels (you’d be amazed at the forces that those skinny wheels have to deal with), we had our certification test. There were a few options, but I chose to build a set of wheels for my own bicycle.
Because there’s nothing like putting your trust in what you’ve built with your own hands.
The bluing on the rims is a reflection of the morning sky behind me.
Strobist info: morning sun providing the back light (hence the shadows on the deck); Canon 580 EXII’s right and left, fired by PocketWizards.
While I am waiting for the results of my certification test (points were deducted as soon as any one of three axes were off by more than 0.1mm), I put them on my trusty bike and gave them a spin today.
Any ride on a well-tuned bicycle, leaving no sound but the whisper of the tires on the road, is a wonderful experience.
But to have that same ride on a pair of wheels that I handmade for myself? Sublime.
Hardened steel on aluminum means that the aluminum has to give.
Small flakes at a time.
Facing a bottom bracket on a bicycle after chasing/cleaning the threads.
When working on the head tube (where your steering tube runs through the frame), the process is different, but still ends up with lots of aluminum bits. That process is called facing and reaming, where the facing is done similar to this, but at the same time a different steel bit is reaming the inside of the tube to prepare the surface for a bearing cup.
The purpose of the facing is to make sure that the ends of the tube are parallel with each other. If not, the bearings and system will not work properly.
This is typically only done once in the life of a bicycle. If the manufacturer is good, they’ll do it. If not, your bicycle shop should have done it before selling it to you. Unless it’s a really cheap bike, when it’s just not worth the time to do it.
It’s all good fun and just reinforces for me what an amazing piece of machinery the bicycle is. Especially as cheap as you can get them these days.
Today was a long day at school. But it was a good day.
We built a set of bicycle wheels from scratch.
I know it doesn’t sound exciting, but it really is, especially when you consider the forces that a wheel that weighs somewhere between 1-2lbs (.5-1kg) has to deal with. Especially when it’s carrying my wide load, bombing down a twisting mountain road.
We jumped right into it, so I didn’t get a chance to get a picture of all of the pieces that go into making a wheel, but it isn’t much. A hub, a rim, spokes and spoke nipples that thread on to the spokes and hold the rim to wheel. That’s where the magic happens.
Our first step was to thread the spokes into the flanges of the hubs. At times it was like wrestling with an octopus (yes, I know what that really feels like), but there was a method to the madness.
Here are the threaded hubs, with spoke nipples and the all-important cotton swabs for precisely applying grease in the right spots.
Once this step was done, it was time to start connecting the hub to the rim via the spokes, which is quite a process. It’s called lacing for a reason. It’s like weaving the spokes in a very specific pattern, in a very specific way so that the forces applied by the rider to the chain are translated into forward motion through contact with the ground.
We do ask a lot of those little 2mm wide pieces of wire.
Once the right (drive) side was laced, here’s what it looks like when the other side of the front wheel needed to be laced. Still wrestling with an octopus.
How loose? I could move the rim side to side several inches. Although it looked like a wheel, it didn’t act like one.
So it was time to tighten. And tighten. And tighten. All to get perfect balance, not only of weight but of tension. Because the weight really doesn’t matter. It’s all about tension.
Get the tension wrong and you’re walking (if you’re lucky).
It took me the better part of the day to get the pair right. Not bad considering it’s my first set I’ve ever built from scratch. And while we had looser tolerances today (±1mm) than we will for our certification test in two weeks (±0.1mm), I was able to dial these sloppy old components to the point that I would have passed the test.
That feels pretty good.
So here is the final set, rear wheel leaning against the backstop, front wheel on the truing stand, with various tools that we used today scattered on the bench. And to give you an idea of how small the relaxed tolerances we had to work with today, the vernier calipers in the lower right are set at 1mm. If that doesn’t help, stack about 5 sheets of notebook paper together. There you go.
While that’s all pretty cool, I like the fact that we had until Thursday evening to get them done. Mine are already disassembled, which gives me plenty of time to focus on the next few days of wrenching.
As I mentioned early last week, I’ve started coursework at the United Bicycle Institute (UBI), which will lead eventually towards qualification and certification to wrench on bicycles.
I’ve wrenched on my own bikes for 25 years, but after last week’s intro class, I realized several things that I had been doing wrong.
Making things harder on myself than the task needed to be.
So while that course was a refresher on most topics, it was casual, running about 3-4 on a 1-10 scale.
These next few weeks will be different, running about a 7-8 on that same scale, with a few days spiking up to 11.
Tomorrow we will be handed an empty hub, 32 spokes, 32 spoke nipples and an bare rim. By the end of the day, we’ll have to have made a completely functional, safe bicycle wheel.
Luckily our tolerances will be pretty loose – ±1mm (±0.039′) since we’ll be using well-worn equipment tomorrow. At the end of the month, we’ll use brand new equipment and the tolerances will be ±0.1mm (±0.0039″).
And I am having so much fun!
Hopefully you are too, doing whatever it is that you are doing.
No prizes, just a chance to get published in the local paper.
There were four categories relating to the Oregon Outdoors – People’s Choice, where I asked for your help pushing my photo up to the top, and three editor’s choice categories – Wildlife, Landscape and People in Nature.
Although I’m not sure how the final tally for the People’s Choice will work out, looking at the voting web page after voting closed showed my Charioteer sitting at #2. Out of 342 entries. That’s pretty humbling. Thank you!!! 😀
The surprise was the phone call I received on Monday. Apparently the editors liked my Sparks SUP photo enough that they declared me the winner of the People in Nature category!
But if you must spend a portion of the weekend indoors, perhaps you’d like to follow my new Facebook page. I will post items there that will not appear in this blog (don’t worry Mom & Dad, I’ll share anything with you some other way).