Book review – Lugged Bicycle Frame Construction

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I have recently been considering getting some brazing equipment so that I could make repairs to frames that have minor failures, rather than sending out to a frame builder for this service.  Having taken UBI’s lugged frame building class a few years back, I had a general idea of what I might need, but didn’t want to go any further until I re-familiarized myself with the topic of brazing.

I found Marc-Andre Chimonas’ book, Lugged Bicycle Frame Construction, on the evil empire (Amazon) website, with what appeared to be some favorable and thoughtful reviews by actual readers.  When the book arrived, I immediately delved into it and have now read if not studied much of the book.

It is written with a dry, understated wit, with an emphasis on the science of frame building.  There are numerous zingers in the text, hidden amongst the tables and formulas.  Consequently, I thoroughly enjoyed reading it.  The author is a physician (which he describes as his “day job”), a writer (of both technical manuals and fiction), and a frame builder.

After reading just the first few chapters, I began to seriously question the idea that anyone can take a frame building class that lasts only two weeks, and from which an actual frame is produced.  Whether that frame is safe to ride may be another thing altogether.  My own frame has several flaws that can probably be corrected, but more on that later.

The book is logically organized and takes the reader through introductory concepts such as nomenclature, frame geometry, measurement and sizing protocols and includes helpful tables for determining angles and lengths for different sized riders.  He naturally recommends smaller wheels for smaller frames, and there is a good discussion of toe overlap and bottom bracket height.  He states his opinions about frame geometry as if they were facts, and that may irritate some readers, but I found it refreshing.  For instance, recommended BB height is 25 cm for pretty much all types of normal road riding.  This is a lot lower than you will find in production bikes.

Another interesting concept that I found both helpful and puzzling was the idea of controlling the variables in frame building.  He differentiates between “operator controlled” variables and “outcome” variables.  Outcome variables are the result of the frame builders operator controlled variables.  But, he describes outcome variables to include BB drop and toe overlap, which in my mind are operator controlled.  At any rate, what is clear is that frame design is a highly complex  undertaking, and one that is aided by software.  He recommends using excel and offers a link to a useful frame design spreadsheet, which is available on the author’s website.

There is a quick trigonometry and metallurgy review (which the author calls optional), and then the theory turns into fabrication as the author goes through chapters on frame parts, tools, mitering, torches, brazing technique, and lug modification.  Again, the author doesn’t hesitate to state his recommendations, even down to a specific brand or manufacturer of a particular tool.  For me, someone who didn’t take shop class in high school, the specific advice is extremely helpful.

After digesting many of the chapters, I decided to drag out the frame I completed 2 years ago but never finished filing or painting.

My frame with front-center at 59 cm - a little shorter than I wanted.

My frame with front-center at 59 cm – a little shorter than I wanted.

I built this frame for myself, designed around a 650b wheel size.  I wanted enough front-center distance to allow for fenders and decent sized tires.  The book uses a formula to determine an ideal length.  I plugged my numbers into his formula and found that I won’t have toe overlap with this frame, so that is a relief.  I did have to use a longer than usual (for me) top tube length to get this much front center distance (combined of course with all the other measurements).  That means I’ll use a short reach stem when I eventually build the bike up.

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One of the things that troubles me about my frame is that it was built so hastily and with so little actual knowledge.  Well, after reading the brazing chapter I think I have reason to be concerned.  I remember having a lot of trouble sanding enough material off the top of my fork blades, and off the inside of the fork crown so that the legs could be inserted without a lot of force.  After hours of filing, I still wasn’t happy, but ran out of time so just brazed the fork legs into the crown even though the fit was tight.  This is definitely a no-n0 – there needs to be enough room for the silver to flow into the joint.

Here are some other details of the frame I built.  Using this book as a resource, I will be able to correct the other two (known) mistakes on the frame.  I may decide, however to build a new fork.  And, I now know what kind of equipment to purchase and how to use it safely, so I am looking forward to being able to do my own small repairs.

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Nice looking BB

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Mistake on the seat stays – they are out of alignment

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Drive size DO not yet cleaned up and filed – you can see I got the tubes a bit hot.

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Aaack! Seriously out of whack shifter bosses – the jig probably got bumped when I turned away to get more silver.

Tools of the Trade

Shop tools

Working on vintage bicycles requires the same tools as a regular bike shop, and quite a few specialty tools as well.  Since I work alone, I have the luxury of maintaining a pretty messy work space, but writing this blog post (plus the snowy conditions outside) gave me some incentive to spiff my shop up a bit before taking these photos.

In addition to being aware of French and Raleigh sizing issues, many vintage components require special tools.  In the middle of a job I will sometimes find that I don’t have the particular tool needed, and I must then go in search of the tool, or try to make my own.  My favorite sources for hard to find tools are:  BikeSmith Design and Fabrication and J.A. Stein.

vintage bicycle tools

These are a few of the specialty tools needed.  From left to right they are: a cotter pin press and a Raleigh fixed cup removal tool (both by BikeSmith Design); atop these is a crank tooth straightener,  next are T.A. and Stronglight crank extractors and a hub axle vise (by J.A. Stein); above these is my homemade fixed cup removal tool and a Park axle vise; and at the right are a bunch of freewheel removers, one of which was made for me by a local mechanic/machinist to remove older Cyclo freewheels.  I still lack a few freewheel removal tools for some rarer and older freewheels such as the English T.D.C. freewheels.

Fixed cup remover

I made this fixed cup removal tool following Sheldon Brown’s instructions.  The tool has worked okay but one fixed cup that I removed was on so tight that my washers were ruined when I finally got the cup free, so I had to re-make the tool.  I definitely like to remove a fixed cup so that I can properly assess and clean the bottom bracket and assess the inside of the frame.  And, often the BB needs replacement or upgrading so it’s great to be able to get the fixed cup out.

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My drawers have the usual stuff, but if you are going to work on vintage bicycles you’ll need a set of S.A.E. Allen wrenches, Lockring pliers (by Lozan), plus files for making frame modifications or cleaning up repairs.  I keep Testor’s paints for touch ups, although I generally only use the clear paint when I touch up a chipped area on a frame.  I do not like to purchase bikes that have had their frames touched up because I have no idea whether the area under the touch up was properly cleaned and sanded free of rust.  If not, the frame could continue rusting right through to the inner side of the frame tube.  That’s why I use clear paint so that any buyer of one of my restorations will not have to worry about what they can’t see under the paint.

005 Vise

A re-purposed wine rack serves as my tube holder and wheel repair stand.  I use a Craftsman Professional vise which is strong enough for anything I have tried.

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I purchased my frame blocks from an internet source that I can now no longer recall.  You need these if  you are going to need to put the frame in the vise.  I also have a Denali angle-finder, digital scale, lightweight drill, and super-wimpy Dremel.  I made the mistake of assuming I would need the smallest Dremel made because of the small parts on bicycles, but I actually really need one that’s a bit more powerful.

Bike shop cleaners

For cleaning, I keep brass and copper brushes on hand (which will not scratch steel), plenty of extra fine steel wool, and various cleaning products.  I try to avoid stuff that’s bad for the environment so I usually use a citrus based cleaner and/or alcohol to clean greasy parts.

Bike shop manuals

No shop is complete without repair manuals.  I have amassed a small collection of vintage shop manuals from frequent visits to my used bookstore, some of which are shown above.  Most useful to me is Glenn’s Shop Manual.  Not only does it feature a doctorish-looking Mr. Glenn in a white lab coat (sans grease stains) overhauling various components, it is the only book which has extensive guidance on overhauling internal hubs and hub generators.  It also has complete instructions for overhauling every imaginable rear derailleur of the time.  If you build wheels, then Jobst Brandt’s book is a must.  Park’s Big Blue Book is only moderately useful – I prefer to rely on the older shop manuals that have much more detailed guidance and plenty of exploded drawings and specifications.

Well, now that my shop’s all cleaned up, it’s time to go back to work!

Resurrecting an Old Friend: a 1976 Centurion Pro Tour

1976 Centurion Pro Tour

I rode my 1976 Centurion Pro Tour for over 20 years before I crashed it back in 1999.  In fact, that crash and the resulting quest for a suitable replacement bike is what has led me here – to an appreciation of the rarity and quality of hand made vintage bicycles and to a side career as a bike mechanic, collector and restorer.

When I hit a car that had suddenly stopped in front of me while going about 20 mph, my front wheel collided with the car’s back end and I went down hard on the trunk.  (Thank you, helmet.)

fork damage

The fork legs were pushed back and the steerer tube was bent right above the crown.

fork damage

You can see the tell-tale paint cracks which clearly indicate a sudden impact.  The fork was definitely toast.

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The frame itself sustained some damage to the downtube (left photo) and top tube (right photo).  You can again see the tell-tale paint cracks right at the lug points, but the cracks are not very pronounced.  And, looking at the tubes and holding a straight edge up to them, I cannot see any significant bends or twists.

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The rest of the frame looks great, with plenty of “buesage” evident in the scratched paint and fading logos.  But, overall, this is one nice frame.  If I could bring this bike back to life with a new fork, and any needed repairs to the tubes, I would be overjoyed.  Interestingly, this frame is “too big” for me – at 54 cm, but I managed to ride all over the place in tremendous comfort.  I did install a stem with shorter reach, plus rando bars (which my Pro Tour did not have originally), and that gave me a comfortable position.  After all, with the really tall frame my stem didn’t need to be tall because it was already even with my saddle height.

Once I remove the paint (to reveal the fully chromed frame underneath!!!), I’ll know for sure the extent of the damage.  Since I am really fond of that baby blue color, I might still decide to paint it again after stripping it, but it will be sad to lose the Centurion logos.  An experienced painter may be able to recreate them.  If all goes well, I’ll be riding this amazing bike once again.

Touring in the San Juan Islands

Centurion Pro Tour – San Juan Islands – c. 1985