Definitions and References

Definitions

I want to define a few terms, acronyms and abbreviations that I will use. This list is not all-inclusive and will be updated as I think of other items to add.

• Jigs and Fixtures -- These terms are often used interchangeably, but they actually have different meanings. I'll be using the definitions from my 21st edition copy of "Machinery's Handbook". If you don't have a copy of this reference book you probably don't need the very latest edition, and can instead pick up a used copy for a much more reasonable price. The current edition is number 31, and I bought my copy new in the early 1980s.

  "The distinction between a jig and fixture is not easy to define, but, as a general rule, it is as follows: A jig either holds or is held on the work, and, at the same time, contains guides for the various cutting tools, whereas a fixture holds the work while the cutting tools are in operation, but does not contain any special arrangements for guiding the tools. A fixture, therefore, must be securely held or fixed to the machine on which the operation is performed -- hence the name. A fixture is sometimes provided with a number of gages and stops, but not with bushings or other devices for guiding and supporting the cutting tools."

  What people frequently call a "frame jig" is normally a structure that holds metal components (tube sheet, castings, forgings) in position for welding (or maybe holding parts in position while an adhesive sets and cures). In other words, it is a fixture since it is not normally equipped with hardened bushings etc for the guiding of cutting tools. There may be provision for mounting a drill jig or align boring jig to the fixture, but the main structure that holds parts in place is a fixture, not a jig.

  Yes, I at one time referred to "frame jigs" instead of "frame fixtures" too, but now I know better. ☺

• Funny Front End or FFE -- Tony Foale uses this term for front steering/suspension mechanisms that are not one of the traditional (such as telescopic forks (telefork), link forks (trailing or leading) and girder forks) head-stock mounted types . FFEs appear on motorcycles built by Tony Foale, Norman Hossack, Claude Fior, Jack Difazio, Jean-Bertrand Bruneau, James Parker and others.
  
• Style and Design -- Here's a paraphrasing of one of many similar definitions that can be found on the Internet: "Style is more concerned with the look of a product. On the other hand, design is more concerned with the basic layout of a product with its core functionality and user experience in mind. " That might be restated as style is about marketing and design is about how something works and interfaces with the user. Marketing is important for commercial endeavors, but not too important to me.

  I'm pretty limited when it comes to artistic abilities, so I will largely avoid discussing "style". As someone who is more concerned with function over form, I find things like many "art bikes" a bit baffling. Yes, they may be built with the highest levels of craftsmanship, but I don't see the need for all the fripperies and weird styling. But as long as the builder is happy with what they built, hurrah for them. FWIW, when it comes to style, Art Deco is a favorite of mine. I prefer sleek over baroque.

• Design for Manufacture and Assembly (DFMA) -- From Wikipedia: "DFMA stands for Design for Manufacture and Assembly. DFMA is the combination of two methodologies; Design for Manufacture, which means the design for ease of manufacture of the parts that will form a product, and Design for Assembly, which means the design of the product for ease of assembly deriving creative ideas at the same time. Critics of DFM from within industry argue that DFM/DFA is simply a new and unnecessary term for something that has existed as long as manufacturing itself, and is otherwise known as engineering design." Even if there is some contention over the use of the term, it is an important concept. Even for a "one off" vehicle, you should try to make it easy to build and assemble (and maintain, too).
• Fabrication -- making a part (or the resulting part) from more than one piece of material. For example, a Moto Guzzi small block swing arm is a single machined casting while many other swing arms are fabrications made from welding together tubing, sheet, plate, and possibly small castings or forgings. I'll try to avoid the type of fabrications that appear in a lot of advertising material.
• Feet Forwards (FF) -- motorcycles with a low recumbent seating e.g. The Creasey Voyager, Robert Horn's EX500-powered racer, a Newall Quasar, etc. See the following definition of Powered Two Wheeler.
• Powered Two Wheeler (PTW) -- I suppose you could say that a bicycle pedaled by a human is a PTW, but I'm going to use "powered" to refer to making the vehicle move by the actions of some non-living device, the fuel for which is carried on the vehicle (to avoid considering the use of wind power ☺) . That may be a combustion engine (internal or external) or an electric motor with a battery or fuel cell. A PTW could range in size/complexity from a small moped up to something like Wild Bill Gelbke's RoaDog. Some people have a very narrow definition of what they think qualifies as a "motorcycle" (this seems to often come up with Feet Forwards vehicles where some riders of conventional bikes say "but that's not a motorcycle") and PTW allows us to side-step those issues. However, some of what I'll discuss will apply to human powered vehicles as well as those with more than two wheels. I've gleaned a lot of good information from articles/books on bicycles, trikes, automobiles and aircraft -- to some degree "vehicles are vehicles" applies to the design and construction topics. I will consider motorcycles to be a subset of the PTW class as are mopeds, but to me FFs are clearly motorcycles. I may use the terms motorcycle and PTW interchangeably.

to be continued . . .

References

These are things I use and find very helpful:

Please contact John Bradley and Tony Foale direct for copies of their excellent books (and Tony's software) that I was pleased to be able to sell for so many years. You REALLY need your own copies!

• A bibliography of technical books from my personal collection. This is in the archived material from the EuroSpares website

• Matweb Online materials information

• RB Racing Many useful calculators and a huge guide to motorsports wiring

• Sprocketeer 2.0 If you need to make a sprocket to machine or to put into CAD, this free application does the job

to be continued . . .

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