Philadelphia ExcursionPosted: May 15, 2011
Drew has concentrated his time on getting his frame building process right, and then having the best machines and fixtures for the job. One horizontal milling machine is used only for tube mitring, and so has the table bolted in place so that the mitring fixture is always dead-centre around its pivot point. The fixture has interchangeable butt-stops of different sizes, which represent the different tubing sizes. This way, the tube length can be measured very accurately.
Drew explained that horizontal milling machines are very useful for mitring tubes, and are very accurate. He showed me a German-made horizontal machine made by Deckel that he said was extremely accurate, and also came with a detachable vertical milling head.
Drew showed me his own design fork fixture, which he made himself. It can measure from the brake hole in the crown, or the crown race seat. Everything moved very well and smoothly, with no sloppy fit anywhere.
To find the exact point of the edge, the width of the edge-finder is then halved to find the centre point of the milling spindle (a parallel bar is used in the machine vice next to the workpiece to give a convenient extended edge).
The exact centre line of the workpiece can now be calculated by halving the measured width of the piece, then moving the table by this distance exactly with the graduated handwheel.
In this case, the piece was a stem/steerer binder made from 4130 chro-moly, which had to be mitred to fit on the stem, and slotted along the centreline to allow it to open and close. A hole saw was put into the milling machine to cut the mitre into the now-centred binder. The mitre was then cut,
..and cleaned up with an end-mill:
The central binder slot was cut with a slotting saw on a horizontal milling machine; the distance from the edge to the centre noted and transposed from the previous exercise.
Drew also showed me his unicrown fork fixture, designed to hold the blades very precisely and in phase with each other. Drew only uses straight fork blades with his road and cyclo-cross bikes.
Next, Drew showed me a newly Tig-welded mountain bike fork, with two cross-pieces between the steerer and the straight blades. There are many angles to be considered when mitring and constructing this type of fork, and Drew showed me a very clever fixture he had just developed for mitring the component tubes.
Here are some more pictures from the Engin Cycles workshop:
Drew takes his alignment datum from the head-tube, not the bottom bracket shell face, and also incorporates seat tube clamps into the surface table, machined specifically for each tube size to retain the centreline with relation to the head tube.
All dummy axles are marked with a centreline to check the centring of the rear triangle with a surface gauge.
Drew defended his stance on owning multiple machine tools by explaining that they were of good quality, and would last longer than the rest of his life.
I also met Simon Firth, a British ex-pat that actually used to work for the same courier company as me in London. Small world. Simon has built frames for Bilenky for years, but is now working with Drew at Wissahickon for 3 days a week, and working on his own frames and equipment the rest of the time. I also had the pleasure of seeing his first frame build under his own new marque, Hanford.
I tagged along with Simon and Joel, who works at Via Bicycle (The Hanford frame was built for him) to a swap meet in Brooklyn, where the bike was going to be shown to the local bike aficionados.
The next day, I rode up to North 2nd St to visit Bilenky Cycles, where I spoke to Stephen Bilenky about his company and took some more pictures:
Stephen Bilenky started building bike frames in 1984. He is largely self-taught, but had lots of vocational training at an agricultural college where he was taught shop skills, repairs and fabrication. He also took more vocational post-college courses in welding and brazing.
Stephen did study under Jim Gittins for a time, who at one time built under contract for Condor amongst others.
Stephen said that 85% of the information needed to start out can now be found on the internet.
There were 5 employees at work at the time of my visit.
Bilenky make fillet-brazed, lugged and Tig welded steel frames, and also some titanium frames.
A CAD program is used to design the frames, and the tubing is cut and mitred by machine. The frames are built using fixtures made by Anvil Bikeworks. Bilenky also undertakes all kinds of frame repairs.
Frame fit is worked out using body measurements, a size cycle or the customer’s current bike.
Bilenky produces between 100 and 150 bikes per year, depending on the type and level of customisation, as the build-time can vary greatly.
Several years ago, Bilenky decided to focus on tandem frames, and as the market was small, they became well-known in this specialised field. This helped the business to grow.
Pre-internet, Bilenky relied on articles in magazines and word of mouth for marketing. Bilenky’s bicycles were reviewed by Bicycling magazine twice in the 1980’s, and also in the 90’s.
Nowadays, Bilenky relies mainly on internet promotion, but shows are also important.
The local Philadelphia market is not particularly strong, so the main market is national and international. At the time of my visit, two frames were being built for customers in Denmark, and another was being built for someone in Japan.
Stephen explained that the company did not get online until 1998, and before that he would receive letters from people interested in his bikes, and reminisced that the only other form of communication was the telephone. I asked Stephen whether he thought an increase in the number of apprenticeships would benefit the industry, or whether he thought it could potentially increase competition too much. He replied that individual frame builders tend to make their own market, so increasing numbers would most likely benefit the industry as a whole, rather than increase competition.
Here are some pictures from around the workshop: