STAINLESS STEEL RULE IN FOUR SCALES
Manufacturer: The Willow Works, P.O. Box 150581, Nashville, TN 37215. Price: $14.95 each postpaid.
HARRY WADE'S GUIDING principles in designing a scale rule were accuracy, longevity, and premium quality. His was also the first modeler's rule in America to offer the scales of 1:22.5, 1:24, and 1:32. The fourth scale is 1:1, or twelve actual inches to the foot. The rule is twelve inches long by three-quarters of an inch wide. It is solid stainless steel with very fine, very readable, indelibly etched markings on a brushed satin finish. It is attractive and exudes quality.
The advantages of stainless steel are durability and, possibly, appearance. You may use a stainless rule as a straightedge for drawing or cutting. It is relatively impervious to many chemicals; at least you may polish away some stains and fingerprints and even little paint spatters if you catch them early enough. It is also a hard enough metal to resist chips or dents.
Some metal rules may have one disadvantage. Occasionally, if the process of applying the markings involves stamping, the metal may elongate. Such elongation is minimal, but it can have a slight effect on accuracy. At the end of a 1:24 scale, for example, 23 feet 7 inches could become 23 feet 8 inches.
The Willow Works rule is computer photo-engraved. Elongation will never occur.
Who cares, you ask? A model maker. He chooses a scale rule for its accuracy. Some judges mark down contest models if their dimensions are a little off. Clearly, the everyday modeler would find such a discrepancy insignificant. But scale rules are supposed to be precision tools, accurate enough for the most fastidious craftsman; why else should we buy one?
If you compare the 1:24 scale of our sample of the Willow Works metal rule to the 1:48 scale of another manufacturer's stainless steel rule at 23 versus 46 scale feet, in theory the markings should coincide. In fact, the 1:48 scale of the comparison rule shows evidence of elongation; it runs half a scale inch longer than the Willow Works rule.
And if you compare the Willow Works 1:24 scale to that of a plastic rule, they coincide precisely. Compared with a plastic rule, it measures one quarter of a scale inch short at the extreme end of the 1:22.5 markings. I don't know whether that bothers you; it leaves me unfazed. I have no idea whose rule is the more accurate, and a quarter of a scale inch at 22 scale feet is insignificant even for a fastidious modeler. The margin of error in full-size structures and rolling stock is greater than that!
Our Willow Works scale rule had only one minor flaw. The mill cut one end a fraction longer than the other. The rule has no "zero" marking. The first line represents one scale inch; "zero" should be at the left end of the rule. But on the 1:22.5/1:24 scales, the left end of the rule extends very slightly beyond "zero", to roughly "minus 1/2-inch". That means you must begin all measurements at the one scale foot mark or you'll be very slightly off.
The flaw is easy to correct. You can make the adjustment yourself with some careful filing or a machinist easily can grind a few thousands off the offending end. The job is so simple, he'd probably do it for no charge.
The Willow Works scale rule is virtually everything the manufacturer intended: It is a premium quality, durable, and accurate tool. Even with the .020-inch extra length at the front end, it is absolutely excellent.--RR
