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Ingersoll-Rand’s Metrication Plan

Ingersoll-Rand’s Metrication Plan

From the March/April 2009 issue of USMA’s Metric Today.

by Don Hillger

The Ingersoll-Rand (I-R) Company plan was to convert to metric in 10 to 15 years, in concert with the availability of metric industrial standards in the US. Their corporate plan outlined specific conversion steps. By January 1978, I-R was designing all new products in metric. Products consisting of partly new and partly existing components were to be metric, too. New parts were hard metric and the rest were soft converted. Existing non-metric products were not immediately changed, since that would have been too costly.

The goal at I-R was to be metric by 1985, a reasonable time period in which to redesign products: not so short as to incur additional costs, but quickly enough to avoid increasing the cost of conversion. For optimum efficiency, I-R wanted to align manufacturing practices to one system—metric—requiring the conversion of machines and manufacturing capabilities. Although the least cost would be to change only when machines were replaced, that would take longer than desired. On the other hand, using dual units adds time to jobs, and for that reason it was desired to keep the transition as short as possible.

I-R recognized that differences in products and markets meant that the timing for metrication needed to vary from division to division, or even from product to product within a division. Their metrication policy included this flexibility to accommodate the needs of the divisions, yet working within the general guidelines of the corporate policy. Each Divisional Metric Coordinating Committee consisted of members from major functioning areas including manufacturing, purchasing, quality control, and engineering.

One of I-R’s first machines to be designed in metric was the J-40 Jackhammer drill. The new, metric design was not only part of I-R’s commitment to metric, but also intended to facilitate manufacture in other countries. Some parts had to be interchangeable with existing units, so those parts were soft converted. Other parts were designed in hard metric.

From the start, I-R was able to purchase many raw materials and components in metric dimensions, including bearings and fasteners, and metal bar stock, sheets, and plates. What was not initially available was nevertheless becoming available quickly as metrication rapidly took place in many sectors of the US.

During the transition, metric fasteners were colored blue to differentiate them from non-metric equivalents. Metric tools were yellow. Products with both metric and customary components had a decal to warn the operator, and new metric drawings had a large METRIC identification label. Dual-dimensions were not used on drawings, but product literature had dual units to comply with customer needs.

An interesting conversion example was the 100 psi (pounds per square inch) standard compressor operating pressure. That specific pressure did not necessarily need to be hard and fast, and changed as compressors went metric and new metric operating pressures were chosen.

Employees were made aware of the corporate metrication policy, and were assured that metric is easy to learn and use. Training was made available to all employees needing it.

A training concept that has been told in other conversion stories was to teach only what employees need to know at the time they need to know it. For example, don’t teach units of force and pressure to employees who won’t be using them. Training also stressed conceptualizing rather than converting, i.e., using metric units rather than converting between units. Since unit conversion can slow learning, everything in I-R training manuals was given in metric units only. With one set of units, the trainees learned the “feel” of the new units.

I-R realized they would have to spend money to metricate, such as for new tools, machines, and training time. However, those expenses were balanced against the benefits of metrication, such as reducing the number of sizes required. For example, in a particular range of fasteners, 10 new metric sizes replaced 32 old inch sizes. Fewer fasteners mean fewer bins for fasteners, fewer drill sizes for fasteners, etc.

I-R worked with the American National Metric Council (ANMC) through its coordinating committees, consisting of various companies and organizations in an industrial sector. Thus, the conversion schedules of different sectors could be considered, helping with the conversion process.

The bottom line is that metrication at I-R was considered to be a long-term opportunity to simplify operations by substantially reducing the number and variety of parts. Economies result from variety reduction. Even with short-term inconviences and added costs, there were long-term benefits that more than justified the cost and effort, and there were no lasting problems experienced on the shop floor. In the end, I-R correctly anticipated lower manufacturing costs and increased international business due to its new policy of using hard metric in all new or replaced products and parts.

Note: Material for this article came from various articles written about the Ingersoll-Rand’s conversion to metric in various literature and metric

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