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Unread 08-03-2006, 12:07
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Richard Wallace Richard Wallace is offline
I live for the details.
FRC #3620 (Average Joes)
Team Role: Engineer
 
Join Date: Jan 2003
Rookie Year: 1996
Location: Southwestern Michigan
Posts: 3,658
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Re: pic: Dented IFI Wheel

The designer of these wheels visited St. Louis back in December, serving as a technical advisor for our FVC demonstration event. He left me a sample 6 inch x 1.5 inch IFI wheel.

A few minutes ago I took that sample down to the CMM that we use to check parts here at Emerson's motor tech center. The results showed that the six hole pattern intended for mounting sprockets is concentric to the bearing hole within 0.004".

Each of the sprocket mount holes was 0.197-0.198 diameter (very nearly 5 millimeters). I'd conclude that the ideal sprocket screw size would be #10, or M5 if you wanted to use metric fasteners. Off center sprocket mounting could result from using smaller fasteners such as #8.

Of course, my CMM results are from a single sample. Close inspection of the holes indicates to me that they were punched, not drilled or bored; from this I guess that the sample was made using the punch tool that IFI subsequently used to make production parts.
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Richard Wallace

Mentor since 2011 for FRC 3620 Average Joes (St. Joseph, Michigan)
Mentor 2002-10 for FRC 931 Perpetual Chaos (St. Louis, Missouri)
since 2003

I believe in intuition and inspiration. Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution. It is, strictly speaking, a real factor in scientific research.
(Cosmic Religion : With Other Opinions and Aphorisms (1931) by Albert Einstein, p. 97)
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