Creating Bushings for Your Grinding Wheels

hi I'm Ernie Conover in this month we're going to talk about the workhorse of tool sharpening the bench grinder any bench grader should be affixed to the bench or to its pedestal that's per OSHA regulations this is a fix to this base and the basis clamped to the bench if you buy an economy grinder which will cost you about a hundred bucks or more for a decent one you can use that grinder you won't get really good viewing guards there'll be little plastic squares on the end of fairly flimsy arms and the guardian won't be as heavy but it's a very useable grinder and there are things we can do to make that grind even better and let's take a look at how we can tune up the average grinder one of the first problems with the a grinder is the wheel and in proof that this is live theater and anything go wrong in taking this wheel off here to show you that problem I dropped it and broke it to smithereens no matter I happen to have another one in the closet so I was lucky and even with a new grinder in any new grinding wheel you want to take it off the grinder like this and just hold it on your fingers like that kind of balancing it and a light tap and you'll get a nice Clarion ring like that out of a good wheel if it has a crack somewhere in it you'll get a sound like a crack baseball bat or a cracked wine goblet it won't ring true the second problem is that grinding wheels are supplied with a set of bushings that go from the center hole diameter right here down to whatever is the smallest shaft size you can mount that on you can see that this bushing is made to terrible standards that there's all kinds of play in that pushing that means even after you lock that down and immobilize it it's actually off-center with a mass off center and that's going to cause you vibration problems so really the thing to do is to turn with our wood lathe a new bushing to start with I've taken a piece of walnut that's a little bit thinner than the thickness of the wheel and I've drilled a 5/8 inch hole with a nice new sharp Forstner bit through it and then bandsaw a circle that's a little bit bigger than an inch and a quarter which is the center hole size in my grinding wheel I have grabbed a scrap piece of wood in a four jaw Chuck and using a beading and parting tool I have brought that tenon down to five-eighths of an inch using this wrench which will actually put it over sized for a 5/8 hole I then reduced it until I have a nice snug fit that I'm sort of pressing that bushing on there like that I'll now use a bowl gouge to bring this down to the correct diameter there we have a nice tight slide fit with no play there we ring test our wheel one more time and make sure that nothing happened while we were turning this bushing and that will just slip that wheel right on there install the flange we'll just tighten that snug but not crazy that we'd crack that wheel in anyway I've turned the guard here to get it out of the way so that you can see this next very important operation and that's to adjust this spark arrestor called a tongue guard by OSHA because it looks like a tongue sticking down from the top of the grinder here you want to adjust this to within about 1/8 inch of the wheel as the wheel wears when the gap gets to be about a quarter of an inch you want to adjust that again down to that 1/8 inch gap what it does is keep sparks from showering down on your heat and and if the wheel explodes or a piece of debris comes around in there it contains things better within the guards and protects you so an important adjustment at this point I'm going to start up the grinder go have a cup of coffee for five minutes and just let it run and a new ground grinding wheel is actually out of round so our next job is to use this diamond dresser which is called a cluster has chips of diamonds in a steel bar and we'll use that to dress this perfectly round and we'll get really good grinding them we can now grind quickly and easily notice how easy I'm grinding the tools not hopping around it all and I'm bringing this scraper quickly to a beautiful and a final diatribe I'd like to make here is that I've been in a number of shops lately where they've mounted the grinder very high like this with the idea that you can see better what you're doing I think that's very unwise all this is sort of thought out over a long period of time to get all this stuff down here with guards over it and so on where that if these wheels come apart or piece of stuff flies out of there it's not so readily going to hit you in the eye still going to wear my eyeglasses but bringing it up here I think it's pretty dangerous keep it down on the bench where it belongs till next time thus Ernie Conover wishing you safe and happy grindy

Channel: WoodworkersJournal

Views: 228,393

Rating: 4.822547 out of 5

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Id: _7OoqJN2L4Y

Length: 6min 20sec (380 seconds)

Published: Wed Apr 17 2013