Popular Woodworking 2005-12 № 152, страница 14
Exploding Grinding Wheels Wreak Havoc
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You Could Put an Eye Out Doing That
I recently retired after a 34-year career with Norfolk Southern Corp. I worked at the Roanoke Locomotive Shop where locomotives were overhauled. We had a huge machine shop, with bench-type grinders and pedestal-supported grinders throughout the shop. I was involved with safety, serving as the shop safety chairman for a number of years. I am familiar with the ANSI standards covering grinding wheels as well as manufacturers' recommendations for their use. I have also seen numerous grinding wheel accidents, involving both small and large wheels.
InJohn Wilson's "$5 Router Plane" (August 2005, issue #149), he makes a comment that could lead to significant injury, including the loss of an eye. Under one of the step photos, he states: "Grind the cutter to a 30° angle. Grinding manufacturers don't recommend side grinding but I've always felt safe." He has, perhaps, never seen a grinding wheel explode at thousands of rpm. They can and will create havoc, and one of the easiest ways to set off a potential catastrophe is to use a wheel for other than its intended purpose.
The reason the manufacturers say not to do this is because the wheel on your standard bench grinder is not made for side grinding. If it were, it would have side tool rests or supports. Grinding wheels can be purchased for this purpose. The Allen wrench could be safely ground into a cutter on the face of the wheel, using Vise-Grips to hold it. One could also use a belt sander, a disk grinder or a small-diameter drum sander in a drill press.
E.L. Noell Roanoke, Virginia
Fear of Dovetailing Conquered
Over the years I have read plenty of articles on dovetailing. After reading them, I was always so intimidated that I never dared try my hand at them.
Frank Klausz changed all that. "Frank Klausz's Final Word on Dovetails" (October 2005, issue #150) and the accompanying charts and pictures were so clear that I immediately went to my shop and got started practicing my dovetailing even without the proper tools (which I have since ordered!). No, my dovetails are not perfect yet (I still need to practice cutting straight and square), but I am making a solid joint and having fun. Thanks Frank!
In a couple of months, maybe Frank can help me move on to the more sophisticated techniques like blind dovetails ... .
Robert L. Grenier Walpole, New Hampshire
The Breaker - Not the Wire - is the Likely Culprit in Laundry-room Fire
In response to "Efficient Shop Wiring" (October 2005), I would not recommend this type of circuit for shop wiring. Back a few years ago, my house caught on fire because of a circuit like that in the laundry area. The dryer was wired for 220 volts and they took one leg and made a 110v circuit for the washer. The breaker got hot but it didn't trip so the breaker fried. Had we been away, the house would have burned. That's my two cents.
Ray Oliver Coleman, Michigan
It sounds as if the fault was in the breaker itself and not caused by the wiring. All wiring needs to be sized to the breaker feeding it. For a dryer with the usual 30-amp breaker, that would be No. 10 — rather heavy to use for a common 110v outlet. But properly wired, an operational breaker would trip before the wire overheated. If your washer outlet were connected to the dryer circuit with a smaller-gauge wire, then the wire could have overheated without tripping the breaker. But that's not the fault of the wiring scheme; it's from using too small a gauge wire for the associated breaker. Because the continued on page 14
Popular Woodworking December 2005