Saturday, August 28, 2010

#29 - Bench Grinder: Tips & Techniques

We’ll finish up our look at Bench Grinders with a few Tips & Techniques.
Every once in a while, we run across something new about Bench Grinders, but most of our knowledge is tried & true, and time-tested.

First off, every ‘store-bought’ grinding wheel that I know of has blotters on its sides. ‘Blotters’ are those pieces of paper, or cardboard, on each side of the wheel. While they might look like just a convenient place for the manufacturer to put warnings and such, they actually do serve a very critical purpose. When a wheel is put on a grinder, there are metal flanges that squeeze against the sides of the wheel. If the wheel had no blotters, those flanges would be tightening up against the actual rock of the wheel and you would stand a very good chance of cracking the wheel. Blotters provide a ‘buffer’ between the flanges and the wheel rock and thereby cushion and distribute the tightening force. Bottom line: Don’t buy a wheel that has no blotters or, if you do, don’t put it on your grinder without making some blotters and using them.

While we’re talking about blotters, they have another use. Most manufacturers put their product warnings on them and one of the major warnings is “Do not grind on side of wheel”. Now, do most of us follow this warning? Probably not, but I am here to tell you that if enough sideways force is applied to as grinding wheel, a wheel explosion is a very real possibility. Years ago, I saw a training film (yes, “film”- not tape or DVD- I’m dating myself) wherein a grinding wheel explosion was created and it is not a pretty sight. Even though I might use the side of the wheel to do some very light & delicate, precise grinding, I’m only able to do so because of my many years of experience with this and I know that I am not applying any sideways force at all. My general advice to everyone is: Don’t grind on the side of the wheel.

Lastly, always keep the tool rest adjusted as close to the wheel as possible, in order to provide the most support for what you are grinding on. Use your safety glasses. Keep the grinder’s eyeshield in place to provide added protection. Make sure the spark arrester is in place and adjusted to within 1/8” of the wheel and always keep an open container of water handy for cooling off your material. If your grinder has a factory water pot, that’s even better. Keep it full.

These hints, and our last two columns, should help you get the most out of your Bench Grinder. Happy Grinding!

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