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Cutter knife through chest
For the WTF file...
================================================= From: http://www.mass.gov/dph/bhsre/ohsp/f...ts/facev21.htm Woodworker Dies When Struck by Tool Knife Launched from Overarm Router A 32-year-old woodworker was fatally injured at work when a steel tool knife was propelled from a rosette cutter. The cutter was installed in an overarm router. The steel tool knife penetrated a polyacrylic sheet (trade name--Plexiglass) shield and then penetrated and exited his chest, sub-sequently ricocheting off the wall before finally landing. The victim was an experienced wood-worker, whose job also included tool grinding and setup of spindle moulders. The knife, measuring approximately 1-5/8 inch square, was part of a cutter head assembly which had been previously used on a drill press at much lower cutting speeds. It was custom designed and built for the drill press, not for the router which is run at much higher speeds. At the time of the incident, the router was set for 20,000 rpm and was being used to make custom rosettes. The maximum permissible speed was not indicated on the cutter head, and there were no written procedures for its use (e.g., the recommended cutting tool speed). The knife was held in the 4-3/4" diameter cutter head by flat shims and set screws. The set screws could not counteract the centrifugal forces generated by the high-speed rotation. ================================================= Now, for ****s and giggles I made the following calculations. I was wondering, using the router speed and cutter diameter, what might have been the speed of that cutter as it sailed towards it's non-thinking victim. (Granted, I'm sure there are more complex mathematics required to calculate this accurately... but this is good enough for my amusement ;-) 20000 rpm 4.75" dia bit bit circumferance = 4.75 * pi = 14.92" 20000 rpm/60 = 333.33 rounds per second 333.33 * 14.92" = 4974.19 inches per second 4974.19 /12 = 414.52 feet per second 414.52 * 60 = 24870.94 feet per minute 24870.94 * 60 = 1492256.51 feet per hour 1492256.51 / 5280 = 282.6 miles per hour So, according my amateur calculations, that cutter blew through his chest at 283 MPH! Moral of the story? Well.... if you have to ask ;-) |
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