Day 1 – Day 2 – Day 3 – Day 4 – Day 5
The frame may have looked finished yesterday, but there was still a lot to do! Today’s tasks:
- Frame shot blasted
- Excess brass filed off
- Any brass gaps touched up
- Excess tube ground away from inside bottom bracket
- Bottom bracket cleared with taps
- Bottom bracket faced
- Head tube reamed, top and bottom
- Seat tube cleared (27.2mm)
- Fork tracking checked
- Rear tracking and frame alignment checked
- Plug air holes (steel rod / silver)
The head tube needs to be reamed so the headset cups sit perfectly. For added precision we used the lathe's axis with the cutting tool spinning.
The cast bottom bracket already has a thread, but running the taps through cleared the thread and removed any remaining traces of the tubes sticking through.
When using external bearings, like the Shimano Hollowtech, the two outer faces of the bottom bracket must be perfectly parallel. This tool does that.
When a tube is brazed at both ends it becomes sealed. This is a problem when applying a lot of heat as the air inside expands and can only escape past the molten brass you're trying to make a joint with. All sealed tubes have to have air holes drilled but we don't want to keep these holes so they are filled with a steel pin an drop of silver solder.
These rather substantial bits of steel sit square in the dropouts and provide the leverage required to encourage the steel into perfect alignment.
So there we have it. In five days I’ve managed to build myself a fine bicycle frame. Dave is an absolutely fantastic teacher. Over the five days he only touched a tool to the frame a handful of times, and only applied the torch once, when demonstrating the more delicate technique required when brazing with silver. When teaching it can be easy for the teacher to teach by demonstration, and end up completing half the work themselves. That’s not Dave, he explains clearly and watches closely providing continual guidance.
It’s with the painter now – come back soon to see the finished bike.
Day 1 – Day 2 – Day 3 – Day 4 – Day 5
The main frame was finished yesterday. Today there are lots of details to add:
- Brake bridge cut, filed and brazed
- Bridge for mudguard cut, filed and brazed
- Bottle bosses drilled and silver brazed
- Rack mounts brazed
- Gear cable stops silver brazed
- Cable guide silver brazed
- Seat tube cut and filed to lug
- Head tube cut to lug
- Forks shot blasted
With the frame out of the jig now, the detail can be added. Two jigs are used to ensure the holes for the two bottles are drilled in the right place.
The walls of the 853 down tube are very thin, as little as 0.4mm away from the butted ends. For this reason the brass with its melting point of around 820°C is a bit risky. Far more expensive silver solder has a safer melting point of around 600°C so is used for the braze ons.
Again, silver solder used for the cable guides on the under side of the top tube.
Here's the cable guide for the rear derailleur on the bottom of the chain stay.
Shot blasting does a great job of cleaning up the joint of flux and any surface oxidation.
By the end of day four, the frame is almost finished!
Day 1 – Day 2 – Day 3 – Day 4 – Day 5
The job list for day three looked something like this:
- Cut chain stays to length
- Cut and mitre bottom of down tube
- Assemble main triangle into jig
- Braze down tube to head tube
- Braze seat tube to top tube
- Braze down tube to bottom bracket
- Braze chain stays into bottom bracket
- Cut seat stays to length and angle
- Braze plate onto seat stays and file
Down tube mitred to fit head tube.
Seat stays are cut to fit the cast dropout in the same way the chain stays were.
Before brazing the metal surface is covered with flux to prevent oxidation which would prevent a good joint forming.
Down and head tubes, in the jig, lug in place, plenty of flux - ready for the torch!
Same story for the top tube and seat tube.
This is the top of the seat stay. It's cut like this so a solid plate can be brazed over the end.
And here I am brazing that plate onto the seat stay.
Day 1 – Day 2 – Day 3 – Day 4 – Day 5
Lots of jobs on day two, some big, some small, most escaped the camera:
- Finalise dimensions
- Round off spikes from lugs
- Mitre top tube – braze onto head tube
- Bend fork blades
- File dropouts smooth
- Cut fork blades to length
- Lathe crown race
- Drill air holes in fork blade
- Drill (and recess) hole for brake in fork crown
- Braze fork blades into crown
- Mitre top of down tube
- Cut out small bridge from bottom bracket (between chainstay lugs)
Here is the top tube mitred to fit the head tube.
The fit is pretty good!
The fork crown race has to be cut to exactly the right diameter for the headset. We used a lathe for extra precision.
Here's the top tube brazed to the head tube.
Here the fork blades are being brazed into the crown.
By the end of day two I have a few sub-assemblies. The top tube and head tube, the seat tube and bottom bracket, the forks are pretty much done and dropouts are on the chain stays. On day three it should come together to form a bicycle shaped object.
Day 1 – Day 2 – Day 3 – Day 4 – Day 5
I spent the first week of April 2012 with Dave Yates in Lincolnshire building myself a bicycle frame. This photo blog charts its progress.
Here are the Reynolds butted tubes at the start of the process. The head tube, top tube, and seat tube are 631, the down tube 853, seat and chainstays 725 and the forks Reynolds R.
Within a couple of hours of arriving I was brazing the bottom bracket lug and seat tube. At this stage we hadn't really thought about the eventual geometry - but it was safe to say it would need these two components! It was really good to get stuck in without having to just talk for hours at the start of the week.
The finished article. Dave's happy so I'm happy. A lot of brass went in, it's gone all the way through and none's on the floor. The joint's good. A bit of shot blasting and filing will clean it up nicely.
I'm using cast vertical dropouts which have to slot into the chainstays. They are cut and filed to look like this.
Before brazing all the surfaces must be cleaned with emery paper and flux applied to prevent oxidation of the surfaces.
Lots of brass makes a solid joint. Still needs lots of filing to make the cast blend smoothly into the stay.
The fork blades are prepared, ready for the dropout in the same way.
Front dropout securely attached to fork blade.
By the end of the first day I felt like I’d achieved a lot. Dave’s place is next door to RAF Coningsby, home of the Battle of Britain Memorial Flight. There were Spitfires circling above the workshop, which, along with the oxy-acetylene torch and the sunshine made for a very special day.
Over 90% of the UK population now live in urban areas. This makes Britain one of the most urbanised countries in the world. In Europe only the principality of Monaco, the republic of San Marino, Belgium and Iceland have higher urban proportions. In 1970 this figure was 77%.
Do the British really like living in urban areas, or are we compromising something?
In Ireland, the figure is only 62%.
Urban population as a percent of total population
Data from here: http://www.guardian.co.uk/news/datablog/2009/aug/18/percentage-population-living-cities and Google Docs
A couple of years ago I wrote a piece (Natural gas, the green choice?) for The Oil Drum looking at the climate change implications of using gas rather than coal. Burning gas to produce electricity produces only around 40% the CO2 emissions of burning coal. However, since methane (CH4) is itself a potent greenhouse gas, its release to the atmosphere without being burnt can quickly compensate for this CO2 advantage against coal. I included this chart to illustrate the point:
On the left, CO2 emissions per kWh for coal and natural gas. On the right, the global warming potential of leaked CH4 expressed as CO2
The key take-away was that if the natural gas leak rate is 3%, the global warming potential of a kilowatt-hour of electricity from gas is equivalent to coal. The details behind the chart are in the original article.
This week the journal Nature has an article (Air sampling reveals high emissions from gas field) presenting measurements from a gas field and suggesting that “Methane leaks during production may offset climate benefits of natural gas.”
Led by researchers at the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado, Boulder, the study estimates that natural-gas producers in an area known as the Denver-Julesburg Basin are losing about 4% of their gas to the atmosphere — not including additional losses in the pipeline and distribution system.
This figure of 4%, their range is 2.3–7.7% loss, with a best guess of 4%, is well inside the danger zone suggesting gas has similar, if not higher, climate impact as coal.
Most of the gas from this site is produced by “fracking”:
Most of the wells in the basin are drilled into ‘tight sand’ formations that require the same fracking technology being used in shale formations. This process involves injecting a slurry of water, chemicals and sand into wells at high pressure to fracture the rock and create veins that can carry trapped gas to the well. Afterwards, companies need to pump out the fracking fluids, releasing bubbles of dissolved gas as well as burps of early gas production. Companies typically vent these early gases into the atmosphere for up to a month or more until the well hits its full stride, at which point it is hooked up to a pipeline.
Gas is often described as the ‘cleaner’ choice, as a transitional energy source between coal and low-carbon renewables. Gas does burn without emitting the oxides of sulphur (SOx) and nitrogen (NOx), traces of mercury, selenium and arsenic, as well as the particulates associated with coal and doesn’t leave the non-combustible slag. Despite this it is increasingly unclear that gas has a significantly lower climate impact and the fracking process itself is not as clean as conventional gas extraction.
This week DECC (that’s the UK Government’s Department for Energy and Climate Change) opened the 27th round of offshore petroleum licensing. This is a process of offering licences for offshore oil and gas exploration and production in the UK administered part of the North Sea.
photo: Creative Commons / Genghiskhanviet
Given the UK’s commitment to carbon dioxide emission reductions and the global agreement to limit warming to 2°C, do we need to spend time, money and energy exploring for more oil and gas to extract from the North Sea? If the limits imposed by the Earth system and our political system’s response establish a total amount of future emissions, isn’t it quite likely that existing, already discovered reserves of fossil fuels are more than sufficient? If in fact it would be very unwise to burn all the current reserves, why bother looking for more? George Monbiot made a similar point as the Government were approving new coal mines: Leave It In The Ground
It strikes me as odd, that neither the press release nor any of the other documentation associated with this new licensing phase even mentions the carbon dioxide emissions associated with the production and inevitable combustion of the newly discovered oil and gas they are hoping for. This omission leaves DECC looking schizophrenic, with one hand attempting to meet onerous emission reductions whilst the other simultaneously desperately scratches out the last remaining fossil fuels available.
Bicycles are great. I ride mine almost every day. To the office, around town, in the countryside, to the allotment, with friends or on my own. The sad truth however, is that an awful lot of people who could ride bikes, don’t. In the UK only 2% of journeys are made by bicycle, compared with 9% in Sweden, Finland and Germany and 25% in the Netherlands (Bassett et al. Journal of Physical Activity and Health, 2008). Along with our lacklustre use of renewable energy, our cycling rates are also languishing at the bottom of the European table. I’d like, and expect, to see more people riding as energy prices rise, the economy continues to struggle and environmental pressures (both local and global) increase. A five-fold increase sounds incredible, but would only equal what many other European countries are already doing, and still represent only half the amount of cycling the best countries manage. It is achievable.
In April last year I spent two weeks in Lincolnshire with Alf and Teresa Webb at The Bike Inn completing my City & Guild’s qualifications in Cycle Mechanics.
Two weeks at The Bike Inn, Lincolnshire
City & Guilds Level 1& 2 Cycle Mechanics (3902) and The Bike Inn ‘Certificate of Attainment’
Since completing the training I’ve been working with Ross Taylor of Taylored Cycles offering the award winning Bristol University Cycle Surgery to staff and students and volunteering with The Bristol Bike Project.
Bristol University Cycle Surgery
The Bristol Bike Project also won an award. We won the Grassroots category of the 2011 Observer Ethical Awards and here’s the video:
This year I’m venturing into the world of frame building, with a one week course, again in Lincolnshire with Dave Yates and another with the soon to be opened Bicycle Academy. I say soon to be opened as they are currently setting up their workshop following a fantastically successfully crowd funding. They succeeded in raising over £40,000 in under a week though the new peoplefund.it project.
Watch this space for my adventures in frame building!
Hat tip, James, Bristol Bike Project 
A bicycle wheel truing stand is a must have tool for any bike mechanic. The shape of the wheel, its lateral (wobbling side to side) and radial (up and down) trueness are a function of spoke tensions. By using a spoke key and tightening either odd spokes or adjacent pairs of spokes, out of true wheels can be gradually straightened out.
There’s nothing fancy about a truing stand, it simply has to hold the wheel firmly in place as you spin it, and have indicators of the two degrees of trueness. Commercial stands are at least £50 and you can pay a lot more. There’s no need though. I learnt to build wheels with Alf & Teresa Webb at The Bike Inn on an old cast-iron stand with perfect results.
Here’s the stand I built, loosely based on Roger Musson’s design from his book, The Professional Guide to Wheel Building:
The completed stand with a 700c wheel.
The upright in the foreground can slide in and out to accommodate a range of hub widths from 100 mm front hubs, up to 150 mm dowmhill rear hubs. The two gauges are free to move around on the white surface making adjustment very fast, no fiddly screws to wind in and out, no levers, and swapping from a 700c wheel to 26″ is instantaneous. The gauges are black plastic which show up great against the white background. The corner gauge is used for lateral trueness with the longer angled one for radial trueness.
Obviously for radial trueness (is the hub in the centre) the tyre must be removed.
In total it cost about £15, I bought the M8 nuts and bolts, the angle brackets and a lump of aluminium for the ‘jaws’. The wood and plastic was all scavenged from the street/skips.
I am still lacking a dishing gauge though, haven’t quite worked out how to make one I’d be happy with yet. Any bright ideas, let me know!