Archive for July, 2012

30
Jul
12

Eight Tubes, Part 4: A Small Aesthetic Emergency

We interrupt the construction of this particular frame set to deal with a small aesthetic emergency. It seems that just when I thought that I had put Old Number One (my first frame building project) firmly in the completed pile, a small issue has arisen that (1) is unexpected, (2) is annoying, and (3) makes more work for me.

Here’s the deal: I liked the way that Old Number One looked in bare metal so much that I tried to come up with a strategy to keep it that way. My solution was to spray the frame with Krylon clear acrylic (satin finish) and hope for the best.

Well, it ain’t working.

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It says “Indoor/Outdoor” right on the can, but it appears that the finish is a bit porous when you don’t spray on an unreasonably thick coat of the stuff. Granted, I might have gone a little light on the spots where I am getting the problems – mostly on the chain stays- in order to avoid runs in the paint. I’ll also concede that human body sweat can be fairly corrosive, except that I don’t think I am schvitzing to the point where it is running down the frame and pooling on the chain stays. That would be (1) unacceptably gross, and (2) biologically unlikely.

So right now I am about to flip a coin to see whether I just assume that I went too light on the clear coat and reshoot where I have problems or stop farting around with it and just re-paint it. I am thinking Merckx orange with a white fork and panels on the down tube and seat tube. Or, easier yet, solid white.

The other reason that I am a little slow on the construction end of things is that I have run out of silver flux, so no brazing for me. That’s probably a good thing, because it has given me some time to think out how I am going to attack brazing up the most crucial parts of the fork – the crown and legs – to make sure that I have good strong joints. Otherwise, I am ready to start cutting metal on the fork…

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16
Jul
12

Eight Tubes, Part 3: Getting Jiggy With It

Ironically, it is a bike race – the Tour de France – that is impeding progress on this little cycling-related project. This happens every July; I come home from work, eat dinner, flip on the TV, and immediately get lost in rooting for whatever hopeless break has gone up the road or holding my breath as the group descends some alpine col. (In the interest of full disclosure, I am a Thomas Voeckler fan…)

Anyway, watching the Tour does allow a lot of time to ponder some of the unresolved decisions that I have about this particular build, especially things like how to braze up the fork so it is vaguely straight, what geometry and sizing will I target, and just what sort of an asshole would throw tacks on the road at the start of a high-speed mountain descent (I am watching Stage 14 of the Tour as I am writing this, Cadel Evans and about a third of the peloton has just flatted, chaos abounds, and the normally unflappable broadcast team of Phil Liggett and Paul Sherwin are sounding like they have The Fear).

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I have come up with a plan: build the fork first so I will have it in hand when I build the frame. When I put together Old Number One, it became manifestly clear that I really needed the fork that I was going to use in hand before I could finish the frame itself.  

Why?

With Old Number One I basically designed the frame around a couple of key measurements:

1. Top tube length,
2. Seat tube length,
3. Head tube and seat tube angle.

The remainder of the front triangle – the length of the head tube and the down tube – pretty much riffs off of those measurements.

Oh…..I didn’t tell you…I don’t have a set of plans or blueprints for my bike. I do know what size and geometry work for me, so it all sort of works out when I start cutting metal. Sure, this method sounds a little Rube Goldberg and I don’t think that Dario Pegoretti or Richard Sachs will be copying my proprietary sizing technique an time soon, but it worked just fine on Old Number One. I ended up with a 55cm frame (seat and top tube) that has a 160mm head tube. Granted, a 160mm head tube is tall, but it makes for a comfortable bike. (This time around I am shooting for a 140mm head tube).

The problem that I had with Old Number One was that, having no plans, I had to figure out length and angle of the chainstays.  Tough to do with no plans. 

The way that I figured out how to do it was a little bit of common sense.  Recognizing that the top tube of Old Number One would be parallel with the road when it was finished and the wheels attached, that meant that if you knew how high the front end of the bike was going to be hiked up off of the ground with the fork attached, then one could figure out where the rear wheel (and the chainstays and drop outs) should go. 

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It actually turned out pretty simple.  On Old Number One, I took the completed front triangle, popped on the headset and fork, put the uncompleted frame in my bike stand, leveled it up so that the top tube was parallal with the garage floor,  and then measured the distance from the fork end to the ground.  I then popped the chainstay in the bottom bracket and adusted it until the distance from the floor to the dropout matched the measurement at the front.   

If you are bored or confused by all of this, just look at the picture of the pretty girl. That’s why she’s there.

So….before I build the frame, I need to have the fork.  Never having built a fork before, I have been running around the shop measuring all the road bike forks that I have laying around. The key measurement that I am interested in (for now) is the distance from dropout to crown, i.e. will a wheel and decent sized tire fit in the fork. Based on this ad hoc survey, somewhere around 365mm seems to be what I am shooting for. That will allow for a 700 x 25c tire, and is also compatible with the brake calipers that I probably will be using.

I haven’t been a total slug this week, however. We did cut some metal. I came up with a simple jig that should hold the various parts of the fork in situ while I braze them in place. Behold It’s crude elegance. Total cost: about $10 worth of angle iron and bolts as well as the noble sacrifice of an axle from an old front hub.

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Next: Strong Language, And The Blue Sharpie Is Your Friend

06
Jul
12

Eight Tubes, Part 2 – The Postman Cometh

It’s like Christmas in July here at The Bike Bunker; my package from Nova Cycle Supply showed up in the mail this week. Tubes, lugs, fork crowns, and all the really cool itty bitty parts that go into constructing a frame set arrived safe and sound.

But I am getting ahead of things.

One of the questions that I have gotten from readers is “Dude, if your blog isn’t going to be the absolute Encyclopedia Brittanica of frame building, where can I go to read up on it?” First, for our younger readers, “Encyclopedia Britannica” is a quaint reference to one of many old school go-to sources of general knowledge that we used to rely on before we had Wikipedia or the internet. We abandoned paper encyclopedias due to the health risks involved in using them; there were the occasional fatal paper cuts from turning the pages as well as the ever-present threat of being crushed beneath the 30 or so weighty leather-bound volumes if they fell off of the library shelf. Plus, there was no nudity.

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Anyway, there are a couple of pretty good books out there to help guide you with your project, ranging from the Paterek Manual (which is probably the best and most comprehensive book out there) to a really useful book by a guy named Marc-Andre Chimonas who (based on the pictures that he includes) builds bikes in his back yard. The Chimonas book contains a wealth of practical advice, and it is relatively inexpensive. Reading it convinced me that I could build a frame in my garage –

Lugged Bicycle Frame Construction, A Manual for the First Time Builder: Expanded Second Edition (Marc-Andre R Chimonas, Raymond Wang: Books)

More thorough is the Paterek manual. You can download an outdated copy of the Paterek manual for free directly from the Paterek website. (He asks for a voluntary donation of $3 if you find the manual useful. Trust me, it is very useful). For the home builder, even the outdated Paterek manual contains a wealth of information and guidance that should be part of your education. Plus, I figure that since I am building an obsolete bike an obsolete manual is just the thing to have.

The Old Paterek Manual

Another very helpful little book was written by a guy named Dr. Paul Proteus. It’s a quick read and lies somewhere in the middle of the spectrum between the Paterek manual and the Chimonas book in terms of detail and sophistication.  You can download it for free here:

The Proteus Framebuilding Book : Dr. Paul Proteus

Bottom line: download the Paterek manual (it is invaluable) for an idea of how an old-school pro would attack the problem and then read the Chimonas book (it’s not that expensive) to get an idea of how a shade-tree bike builder would approach the project.  I tried to find a happy medium between the two.

I also have been asked whether you need a boatload of “special” (i.e “expensive”) tools. The answer is, well, yes. You need to have access to a decent workshop; you aren’t going to be able to pull this off in your kitchen unless you regularly prepare food using a bench grinder and a drill press. That said, Number One was built with very few specialized tools. Basic cutting was handled by a hack saw. I mitered the ends of the tube using an air-powered die-grinder. This is a pretty heavy duty tool, but a Dremel tool would work just well (if a bit slower). I aligned things using a basic carpenter’s level, a simple dial protractor that cost around $9, and some string. As for a torch, I used a $65 MAPP gas torch and joined the tubing using silver brazing. The torch was cheap, but the brazing rods ain’t – 56% silver rods cost around $10 – $15 a pop, and I used up five or six of them.

As for bike-specific tools, you do need access to a headtube facer and reamer, a seat tube reamer, dropout alighment bells, and a bottom bracket tap. Any decent bike shop will have the headtube facer/reamer and the bottom bracket tap. I did buy a nice ajustable seat tube reamer for around $100 – none of thelocal shops had one. I eventually did buy my own headtube facer/reamer. I also had to make one or two tools – there was a simple jig that I copied from the Chimonas book that i used to align the rear triangle (about $10 in angle iron and bolts at the hardware store) as well as a neat little guide that I built out of bar stock to help attach the dropouts to the chain stays and seat stays.

But enough of that…on to the goodies. You certainly need a much smaller box to ship a bike before it is built than after you finish.

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I purchased my tubes, lugs, and small parts from Nova Cycle Supply. The tube set (head tube, seat tube, down tube, top tube, chain and seat stays) is one of their house brands. It’s “regular” sized as opposed to larger “oversized” tubing like I used on Old Number One. It’s all double butted chromoly tubing, and it sure looks nice in the box.

The lugs and bottom bracket are made by Long Shin, and they are somewhat fancy. The head tube lugs are set up for a steepish 74 degrees, as is the seat tube. This will be a bit racier than Old Number One.

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This project will have an additional element that I didn’t tackle with Old Number One: the fork. I bought a fork kit to go with it. Forks can be tricky because (1) they require you to bend the fork legs to get that nice curve, and (2) if you screw up you can die. The kit that I bought builds a straight legged fork with a 7 degree rake built into the crown. No bending of tubes for me. The fork ends are these little nice castings that go on the end of the fork legs. Way cool.

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Next: The Most Important Tool In The World…A Blue Sharpie.

02
Jul
12

Eight Tubes Part One: Ego, Vanity, And Another Bike Project

So, do you want to watch me build a bike frame?

Despite the rather abysmal numbers that this particular blog generates in terms of daily visitors (rather understandable given my utter lack of public notoriety and an absence of any salacious content whatsoever on my website) a number of my friends (including my imaginary internet friends over at http://www.roadbikereview.com) have convinced me that I should take the time and effort to write about my next bike-related project: building a steel frame and fork from scratch.

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That’s easy for them to say. They aren’t the ones who have to take the pictures and come up with the witty banter.

Anyway, I am going to build another bike frame, and I might as well document its construction for the edification of my friends and for posterity.

It is probably appropriate at this point to set expectations and to give folks a little background as to what to expect over the next few months, if they care to stick around and watch.

First, I don’t do this for a living. I work out of my garage. This will not be a complete tutorial on how to build a bike frame. What I intend to try to capture here is how an average schmoe with some mechanical aptitude and access to a decent workshop can build a nice frame that will be state of the art circa 1970.

Second, I work slow. I spent a lot of time with Old Number One just pondering and problem solving. Having learned a bit with my first effort, I expect this frame to be built a little quicker. Still, I expect to be at it for a few months. My plans are to update this blog once a week, whether or not I make a lot of progress. I also to include a lot of pictures – its easier to show you what I am doing rather than yammer on and on explaining my rather well-developed opinions on brazing chain stays or conducting an erudite discussion on the fundamentals of cable stop placement.

This will be my second frame, which means that I am at still at the stage where I’m genuinely pleased if at the end of my labors I have produced something that resembles a bike. While Frame Number Two will be lighter and fancier than Old Number One, Ernesto Colnago and Dario Pegoretti certainly won’t be losing any sleep worrying about having to compete with my handiwork. Being a rank beginner also means that I am taking a bit of a risk here by agreeing to document my project; if I fail, it will be a rather public failure (assuming, of course, that anyone is actually following along). That said, my first frame (Old Number One) turned out fabulously well. I don’t think that there is a terribly big risk that I will screw the pooch here.

Pride, they say, goeth before a fall.

Next: Tubes, Lugs, And Other Stuff That Arrives In A Plain Brown Package




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