‘I . . . can . . . do . . . that.”

These four unimposing words, when strung together to make a simple declarative sentence (before actually thinking about the question at hand) can cause more trouble than you might ever imagine. Flowing so effortlessly between the lips the words are gone in a microsecond, typically to places from which they cannot be retrieved.

This is exactly what Joe Edwards, president of Smart Part Inspection, said to his best customer when he was asked if he could measure a box of gears for him. And why shouldn’t he measure a box of gears and make his customer happy?  After all, Joe Edwards was a measurement wizard—so good that customers flocked to him when he left Parts R Us manufacturing to start his own contract inspection business.

This customer, Shifty Equipment Corporation, was gearing up production for the third sales year of their wildly popular Trail Bounder Snowmobile. Orders were up and fine-tuned manufacturing processes would insure more profitability. One thing they did was to reduce costs by contracting alternate sources for the gearing used in these peppy babies.

Unfortunately, some of the transmission assemblies made from these new gears were producing a barely audible but distinctly disconcerting grinding sound not heard in previous years. Both of the new offshore gear suppliers insisted, through a translator, that their gears were not the source of the problem. 

Eager to please, however, each would be more than happy to correct any out-of-spec (or even in-spec) variation that might be causing the problem. They just needed to be told, not in a foreign language, but gear language, exactly what the problem was.

So Joe Edwards returned to his shop with a box of gears – new ones and ones used in the previous years’ production and an armload of prints. He promptly deposited these on the CMM table of his best measurement technician.

“You have a loose gear or something?” groused the technician. “I don’t know how to measure these, let alone generate the evaluation reports.”

The boss countered, “Surely you, who routinely measures aerospace components, intricate medical devices, and unforgiving fuel injection units are not going to be flustered by a few simple gears. You have a fine high accuracy CMM, exceptional, multi-faceted CAD-based measurement software, and you’re smart like a fox. You can measure anything you set your mind to.”

Not wanting to disagree with his boss, the technician said, “I can do that.”

So he set the gears and prints aside and cleared up his other work on Monday and Tuesday. On Wednesday he immersed himself in the intricacies of gear measurement. By Thursday afternoon, he had programmed the CMM to inspect several of the simpler gears and he’d generated what he thought to be very respectable comparative reports.

It all hit the fan Thursday afternoon when Joe got a call from his guy at Shifty Equipment. The Shifty guy wanted to know if he could have the reports at the beginning of the week because his management was getting nervous and decided to send him overseas on Tuesday to talk with the gear suppliers. He needed the reports to take with him, so that he actually had something to discuss with them.

Needless to say, Joe was not happy to hear that his crack measurement guy would have the job finished in a couple weeks if he worked overtime. “These formulas are really complex,” he told Joe. “And the terminology is confusing. Sometimes different labels are used to define what seems to be the same relationship between the features. I’m not always sure which is which. And the equations used for some of these evaluations are just unbelievable.”

“Why don’t you just send the rest of these parts over to the boys at Superior Part Inspection Services? They measure a lot of gears and have special equipment. They could turn this around,” the technician said.

“Not on your life,” said Joe, who grabbed the box of loose gears and marched back to his office.

From four o’clock that afternoon until about midnight, Joe the master CMM guy in his shop plodded away at programming a complex helical gear for measurement and analysis, and got approximately nowhere.

Roused from his sleep, Sleuth took Joe’s phone call at a little after midnight. In his drowsy state, Sleuth listened politely but said very little, except for the ominously foreboding simple declarative sentence, “I . . . can . . . do . . . that.”

Sleuth had actually measured gears earlier in his career. He used dedicated gear machines, which were very expensive and ultra-precision CMMs that were exceptionally versatile and enormously expensive. He reasoned that using a good CMM and versatile general-purpose software he could develop an efficient process that Smart Part Inspection could occasionally use to measure the kind of gear his customers needed to evaluate.

It took the Sleuth the better part of the weekend working by himself at Smart Part to convince himself that he was wrong. With the Tuesday deadline fast approaching, total embarrassment was looming. It was then that Sleuth did what any red-blooded guy will do when about to be trapped by his own cavalier declaration of  “I . . . can . . . do . . . that. ” He surfed the Internet to see if he could buy his way out of a bind.

Sleuth got lucky and found a dealer who sold an add-on module to the CMM software used at Smart Part. It was neither flashy nor versatile—no CAD stuff --just menus to fill in information from the prints about the gears and analyses required.

“Locate the probe on the gear and tell it to go,” said the dealer.” Soon the system will be spitting out annotated graphical reports that gear guys anywhere in the world can understand.”

The hardest thing sleuth had to do was convince the dealer to come over and install the demo right away. Measuring the gears was embarrassingly simple. All he did was to fill in the blank with spaces such information as: pitch diameter, # teeth, profile angle, etc. The program automatically measured and analyzed the gear and spat out a graphical report with annotations calling out all of the desired information. He completed the work Monday afternoon. It was obvious from the reports that there were subtle differences between the gears that made the upsetting sound and the ones that didn’t.

The next day, the Shifty Guy flew off to parts unknown with actionable information that would get his gears to stop grinding. Sleuth went home, crawled into bed and meditated on the unexpectedly happy notion that he didn’t always have to know everything about everything.

EM Sleuth is sponsored by Wilcox Associates Inc, (www.pcdmis-ems.com), part of the Hexagon Metrology Group and makers of PC-DMIS measurement software. Contributors to this article include: Don Ruggieri, Senior Applications Engineer, Wilcox Associates, This e-mail address is being protected from spam bots, you need JavaScript enabled to view it ; Rob Fabiano, Sleuth iIlustrator, This e-mail address is being protected from spam bots, you need JavaScript enabled to view it and Joel Cassola, Writer, This e-mail address is being protected from spam bots, you need JavaScript enabled to view it