[CR] F.W. Evans jig

Example: Framebuilders:Jack Taylor
Date: Sun, 07 May 2006 01:17:33 -0400
Subject: [CR] F.W. Evans jig
From: "Doug Fattic" <fatticbicycles@qtm.net>
To: "classicrendezvous@bikelist.org" <classicrendezvous@bikelist.org>

Last week I wrote about my recollections of my visit to the shop of F.W. Evans in London in 1975 while on my way home from learning framebuilding at Ellis-Briggs. I was allowed to go into the basement where the frame shop was located and talk to their framebuilder at that time, Harry Healey (at least I think it was Harry). I took a number of pictures of his clever apparatuses including Harry's frame fixture. This brought to light various members scanned copies of old Evan's catalogs. Nic Henderson of Newport, UK wondered if "the Evans Universal Cycle Frame Jig" pictured on the front of one of his catalogs with this Evans quote underneath "the Sure Foundation For Truth in Cycle Frames is an Accurate Jig" was the jig I saw Harry using. Well I wondered too of course. Peter Brown of Lincolnshire, England kindly e-mailed me a scanned copy. To my great surprise when I opened it, I didn't see Harry's fixture but rather something very similar to what I use to design frames. Whoa! This brought up a lot of questions in my mind but before I get started on that a word about framebuiders different methods and the influences that created them.

Evans (in his writings in his catalogs) wasn't shy about promoting how his true one off custom designed frames (the Evans way) differed from mass produced ones built to a standard design driven by the need to lower price rather than achieve the best results for the rider. In addition, he described the value of the method he used to get this individual result and it was based on the jig he used. This was fascinating for me to read because he was using the same logic I use today to explain how to get an individual rider's position and bicycle use into a frame design. He also wrote about his design improvement evolution. Before he started using his "Evans Universal Cycle Frame Jig" he drew the design out on paper. The problem with this approach is that somewhere in the process, it is possible to see some frame balance going out of whack (i.e. too much toe overlap) and out comes the eraser to start over. He initially started with small scale drawing (instead of a full size one) to conserve time to see if this individual design was going to work out. After several of these small scale drawings bore fruit to an acceptable design, he made a full scale drawing that was the basis for building a custom frame. His newly invented fixture allowed him to arrive at a functional individual frame much quicker than paper drawings - especially when considering the ease of needed revisions. He reassured his potential customers that this was to their advantage because "any savings of time that can be passed on to the customer in the form of reduction in price will be rightly welcomed." Oh sure FW, I bet your dropped the price of your frames drastically when you started using this jig.

Now if list members will be patient with all the information this brings up, I'll continue. One of the challenges of building a true custom frame is taking a rider's specific seat/handle/pedal position and using those dimensions as a basis for frame design rather than making a frame to standard dimensions and adjusting bicycle components to achieve the desired individual position. The advantage to a builder (even a lot of custom builders) to build to a proven standard design is enormous. This type of standardized "custom" frame could be represented by a Masi Gran Criterium. There is much less struggle to make fit lug angle availability, things can be made in batches, jigs don't have to be totally reset, etc. If I remember how Faliero did it, he used already made master frames to set his jigs. These things add up to lots of time and effort savings for the builder but aren't necessarily to the advantage of the rider (accept for the price). In other words, custom builders don't all build true one-of-a-kind made-exactly-to-a-customer frame.

Even now - particularly in the States - a full scale drawing is the most common way of designing a custom frame. However, when I was touring various framebuilding places in England, I saw a number of Evans' type of fixtures. We didn't use one at Briggs. They have a wonderful jig there with tube holding parts coming off a cast iron flat table. It was one of the reasons I wanted to learn there. On the wall behind their massive 3' X 4' flat table/jig is hanging up a old Evans type of jig they must have used before the big table was machined. It serves as a fork holder now. The idea for mine came from a similar jig I got with Johnny Berry's shop equipment. His design fixture looked almost exactly like Evans (from what I remember, I sold it years ago). I'm curious where the idea originally came from. Evans says in one of his brochures he invented it and in another he improved it (as in improved an earlier one he made or the idea from another builder?). I'm curious what other British builders use an "Evans Universal Cycle Frame Jig" and where they got the original idea from. Since Berry in Manchester and Briggs in Yorkshire and Evans in London had fixtures like this, did the idea come north or go south? Or is it just so logical that it arose several places by itself?

Thoughts on this type of fixture and how a custom design is achieved from rider position was debated on the framebuiders list last Sunday by Richard Sachs and myself if anyone is interested.

More to say on this subject but I'm long out of time and space,
Doug Fattic
Niles, Michigan