Quality Magazine

Case Study: Bore Measurement Times Cut in Half

November 1, 2003
A Fowler/Bowers pistol-grip bore gage checks Schweizer Aircraft Corp.'s helicopter idler pulleys.

A Fowler/Bowers pistol-grip bore gage checks one of Schweizer Aircraft Corp.’s helicopter idler pulleys. Photo: Schweizer Aircraft Corp.


Schweizer Aircraft Corp. (Elmira, NY), the country's only family-owned aircraft manufacturer, is busy at work to more efficiently and reliably inspect 100% of the parts it makes.

As a maker of a diverse range of aircraft products such as helicopters, agricultural and reconnaissance aircraft and special-purpose unmanned vehicles, as well as parts for Boeing, Northrup-Grumman, Sikorsky and Lockheed-Martin, the company is giving closer attention to upgrading its in-processing inspection operations. The greatest attention is placed on operations that can be performed directly on the production floor by manufacturing personnel.

"We need instruments that can help us to continually produce parts of known value," says Jeff Waters, inspection manager at the 400-man organization whose aircraft products operate in more than 70 countries. Among the more recent metrology acquisitions is a versatile Bowers electronic bore gage available from the Fred V. Fowler Co. (Newton, MA) that has cut in half the previous measurement times and checks tolerances of 0.0005 inch in the many precision-machined products it manufactures.

"We formerly relied on vernier-type inside micrometers for this assessment program, but we found inconsistent results that didn't fully meet our rising standards. With the Fowler/Bowers Holematic Mark II gage, all anyone using the instrument has to do is insert the probe into the bore, squeeze the trigger and get the reading quickly," Waters says.

The pistol-grip bore gage has a resolution of 0.00005 inch, a large, easy-

to-read LCD swivel display, and two pre-set memories. Heads that are above 0.5 inch in diameter are fitted with tungsten carbide measuring anvils. Special anvils are used for threads, splines and slots. "The way this gage is designed," Waters says, "gives a constant pressure around the anvils. It's automatic and simple, providing the consistency we want, no matter who uses the instrument."

Production manager Rick Kent says gages are calibrated at least every six months. The ISO 9000-compliant company values new inspection equipment like the electronic bore gage that takes minimal training to use. "One of the benefits to us with our focus on quality," he adds, "is that we have reduced our scrap rate substantially, particularly for our bearing bores, tail rotor transmission housings, pulleys and a variety of other internal bore components."

Fred V. Fowler Co.

(800) 788-2353