What do the random letters that are stenciled on the sides mean?
http://www.modeltford.com/item/4611-11.aspx
Just wondering.
Talk to RV Anderson. He knows all about that, in fact, he even puts those letters on his new ones.
I modestly submit that I built the coils in the photo. Information about the stencilled letters is incomplete and much of it is based on many years of personal observation of thousands of these early units.
The letters aren't quite random. The following is an excerpt from an article I'm working on:
"It appears that, of all the different coils that Heinze built, only those built for the Model T have the letters. The first time they appeared was in 1911. Since the coils built for the T had no contact spikes on the bottom (like the Heinze coils used on the Model S) that held the coil in place in the box, an attempt was made to help keep the coils from bouncing around by using a mortise and tenon style joint between pairs of coils. To allow for the joint, the coils were made with one thick side. Two of the coils had the mortise and two had the tenon. They were installed in pairs this way, with their thick sides adjacent. These coils were stencilled with an "M" for the tenon coils and and "F" for those with the mortise. It has been surmised that these letters stood for "male" and "female." This may or may not be correct but I've not seen anything that definitely refutes it.
A bit later on in 1911, the joints was eliminated and the coil box lid was made with a couple of wood strips that bore on the coils' metal tops to keep them in place. The coils' one thick side was retained, however. These later coils with the thick side but no joint were stencilled "L" and "R" (probably for 'left' and 'right') and continued to be installed in pairs. A bit later yet, the stencils changed to "Y" and "Z" and these coils, still with a thick side and still installed in pairs, were continued into very early 1912. The exact significance of the Y and Z is unknown but one theory holds that since there was a very large Greek immigrant populace at the time in Lowell, MA, and no doubt many of them worked at the Heinze factory, the new letters may have guided Greek assemblers who didn't read or write English. There could be something to this theory since many Greek names do in fact begin with a Y or a Z.
As the thick-side coils were used up and that construction was no longer needed, the simpler unit with uniform-thickness sides appeared. These coils were installed individually and not in pairs. The first of these was marked with a large upper case "I". Again, exact significance unknown but this letter marks the "typical" 1912 coil. At some later point, the style of the letter changed and, while still an upper-case "I", it was much shorter and wider. At about the same time, there was a change in the arrangement of the ratchet and the nut post on the top of the coil. Still later, late in the 1912 model year, there was a change in the points. They were now made of a single piece of spring steel and are generally referred to by Model T people as the "1913" style. These coils' stencil was a large upper case "K".
Late in 1913 Ford standardized its coils and for a time, Heinze supplied coils and (metal) boxes to conform to the new design. These coils were markedly different from the wood-box units. Not a single part except for the four brass wood screws that secured the metal tops was the same. Even the contacts were in different locations so they could be used in the new Ford metal coilboxes. These coils were stencilled with the letter "O". Some of this type coil were not stenciled but had a large, diamond-shaped ink stamp on the side. This stamp contained the Heinze name along with the month and year the coil unit was built."
copyright 2012 by R.V. Anderson
The forthcoming article will be amply illustrated; its point is to chronologize the coils for accurate dating and will include separate studies of the Kingston and J-B coils as well.
Wow! Thank you. Would have never thought about them using mortise and tenon and making the coils in pairs. It all make sense.