The online magazine on the history and operation of vintage scale model trains in American OO gauge

Monday, July 12, 2010

“OO” Railway Notes: F. D. Grimke and his Series on OO Gauge, 1931-32. Part I: OO, HO, and Track

One problem in looking at the early history of American OO is that the extremely useful Model Train Magazine Index starts in 1933 (Model Craftsman dates to 1933 and Model Railroader to 1934) but OO and model railroading as a hobby was around before that. I had seen references to but had not until this summer been able to read a series on OO gauge that was published in The Modelmaker in 1931-32. This series of articles was by the single person most responsible for the development of American OO (4mm scale, ¾ inch gauge), Frederic Drayton Grimke.

The very first article in the first issue of The Modelmaker in January, 1924 was “The Construction of Model Marine Steam Engines” and it was part I of a series by Grimke. He was a frequent contributor in early issues and was also an early officer and later Chairman of the New York Society of Model Engineers, which was organized in 1926 and still exists today (check their website! More on them another day). Grimke was well versed as a machinist and worked with speed boats and model trains. A letter to the editor from Grimke that was published in the September, 1929 issue reveals some of his professional background: “For over six years I have worked in the electrical engineering department of a public utility corporation, and every day of that time, I have handled blueprints and drawings. It has been proven that a person cannot check his own drawings.” His interest in accuracy of scale drawings is evident in his articles, and in this series I will be featuring his drawings as published with the original articles.

While much could be said about Grimke and Thuillgrim, the first OO manufacturer (active from 1930-32), the specific topic I want to focus in on is the series of articles on OO published under the title “'OO' Railway Notes.” Grimke and his firm Thuillgrim had been given a big boost as they were the cover story of the March, 1931 issue, as related in this prior post. The series as it plays out reveals that he really was on the very cutting edge of the curve that created and defined American OO and HO scale as constructed in the United States.

The first article in the series is in the April, 1931 issue and is largely on the topic of trackwork. A first important note that would not be obvious if you had not been looking for it is that to this point in the run of issues of The Modelmaker there had not been a single reference to HO scale. In this publication to this date whenever any scale smaller than O was mentioned it was always called OO, but some of the early references to OO models are certainly of models we would call HO models today. It seems to have been their editorial policy. Grimke was very aware of this and sets out to clarify the matter right from his opening paragraph and lays out his process for choosing OO.
Gauges smaller than the Quarter Inch or Seven Millimeter Scale have been built and successfully operated. The two principal smaller gauges are the 5/8” and the ¾”. The Scales are 3.5 and 4.0 mm. respectively. They are known as the “HO” and “OO.”…

Before the 4.0 mm Scale was adapted, plans, side elevations, and cross-sections of locomotives were drawn to the following scales: 1/8”, 3.5mm, 4mm, 3/32” and 3/16”. The drawings were superimposed on each other. The 1/8” and 3/32” were discarded as being too small. The 3/16” was discarded on account of the slight difference from the ¼”. That left the 3.5 and 4.0 Scales. Which of the two?

In England, the question is still open for debate, and there are arguments both for and against each Scale. Looking at the question from a practical point of view, there is much to be said in favor of the 4.0mm Scale. There is the difference of 0.5mm to every foot. Thus a much larger locomotive, both in Length, Height and Width, can be designed. There is a difference of 3mm in the track gauge. The “HO” is 16mm Track Gauge. The “OO” is 19mm Track Gauge. The actual difference between 19mm and ¾” is only 0.00197”. And so equipment will operate as equally well over a 19mm or a ¾” Gauge Track.
Grimke then turns to some specifics on track, suggesting a mainline curve radius of three feet and a minimum of two feet. There were no existing standards, and in his drawing with the article he defines standards for switch frogs. He suggests the use of cast frogs rather than building them up each time. Presumably these were to be produced by Thuillgrim, but they are not specifically mentioned in any advertisement although they did sell brass rail. Note that the smallest is #6.

The next segment of the article in the May issue has a couple more notes on track, as some information we might find interesting today had obviously been cut from the previous issue.
The Author regrets that the Editor was not able to use the various Standards Sheets, kindly supplied by Thuillgrim Models, to illustrate these notes.

They were standards for single and double track, crossover, wheel and axle standards.
He explains also that all the standards developed are metric for simplicity. As operation will be by outside third rail the May issue does have a few notes additionally about third rail supports.
The Supports as designed were not successful, and #3 R. H. Brass Wood Screws ½” long were substituted. The only alteration needed is to widen but not deepen the slot, so that the Third Rail just fits in without having to force it in. After the Third Rail is in place, it should be sweated to the screw.
When we continue the series will turn to the very important topic of wheels.

Continue in 1931-32 series

No comments: