Abbreviations and nomenclature

This is a list of abbreviations and nomenclature used in other discussions on the engine turning/guilloché forum. Please add to this thread if you feel something is missing.

A=amplitude. The distance from the depth of the lowest trough, to the top of the highest peak, in the pattern.
P=period. The distance along the pattern from the top of one peak, to the top of the repeated peak.
Ph=phase. How much to shift the pattern in relation to the work piece. Can be expressed in degrees, fractions, or distance.
X=distance the cutter is advanced from left to right between cuts.

Books and reference material

Matthews= Martin Matthews: Engine Turning 1680-1980
Daniels= George Daniels: Watchmaking 4th Ed ISBN: 978-0856677045 Chapter 13: Engine-turned cases and dials.
Well, at the risk of sounding wonky, if you're going to talk math then I'd suggest using conventional symbology for a few of those terms:

ƒ (or f) = frequency
λ = wavelength, (non-time based "period")
ø = phase (although in mathematics this is typically expressed in radians, we understand that it can be described as distance)
α,β,γ,δ,... for specific angles and θ for generic
cap letters (generally) for straight line lengths, curve lengths, and constants
d,ø = diameter (use ø in non-confusing context with ø=phase) (ø is conventionally used for diameter in drawings)

I do recognize that typing in greek letters is more or less difficult depending on your computer and keyboard and I have broken this arrangement many times when I use ø as an angle just because it's harder to get "θ" typed in. Anytime an equation is introduced, terms should be defined, anyway, and I think people are going to use what they want and what is easiest for them not only to understand but to type and convey thought.

Wonk, wonk :)

I agree that proper symbols would be nice, but honestly not practical for most of us. I'm writing on my iPad most of the time and using most of those symbols would make writing here impractical. I'm suggesting use of more common characters to make life easier. I've also chosen to continue using the nomenclature that's in use in text common to this type of work. If we want to start changing that, we'll get a lot of confusion.