Vibrating grinder returns

Take the stamped washers off the machine.

Take them outside.

Throw them as hard as you can.

Machine new ones and quit pissing around with the stamped junk.

At least, machine a new inner one, but a pair would be much better.

You will see a great improvement.

The stamped parts are cheaper to make, at a million units per order. They work well enough to sharpen lawnmower blades, if a user does not know any better. That's why they are used.

Cheers Trevor Jones

That could work, if they are machined closely enough. Lee Valley usually has good stuff.

Thanks,

Joe Gwinn

Thanks for the offer Gunner, but I fear that Harold is right.

Harold, I don't think the shoulders are buggered, as they are protected by a pair of hardened steel spacer washers I added soon after the grinder first tried to shake the world, but still they might be crooked. I think I tested that, but don't recall. Given the mechanical leverage, it would not take a very large error, and it would be hard for me to measure such an error directly. A tight-fitting machined thick flange washer would get its alignment from the shaft cylinder versus the much smaller shoulder.

If I recall, there are center countersink holes at both ends of the shaft, so it should be easy to clean the shoulders up on a lathe if needed.

Joe Gwinn

If you have a mill, then perhaps you can use it as your lathe. Clamp a suitable square HSS bit in your vise, and use the table motion to feed it along the axis of the spindle. Use the knee (or spindle feed) to work the bit along the OD of the workpiece. (I'm assuming a vertical mill, here.)

Hardest part will probably be holding the washer for machining. Is there such a thing as an R8 emergency collet? Maybe you could hold a piece of 3/4" stock in a collet, and use the cutter in the vise to turn it down to the same size as your grinder spindle, leaving a shoulder slightly shallower than the thickness of your washer. Then drill and tap the end for a bolt and smaller washer to hold you grinder washer on the stub (actually, you'd probably do that first so that you wouldn't have to disturb the setup once you turned the shoulder on the stub). If you have a 5/8 expanding mandrel, or can make one, that might be the hot ticket, to leave more of the workpiece exposed to machine. (If you take the stub arbor, countersink the hole in the end, slit it in several places with a hacksaw, and use a flathead screw riding on the angle of the countersink to force out the sides, would that hold enough for light cuts...?)

Just thinking aloud here, really. I'm sure someone else here has been- there-done-that and will have a more refined take on it... --Glenn Lyford

On one of my field trips, I scrounged a piece of scrap steel 4"x12"x1" thick. They gave me a woven poly bag to carry it in. When it came time to check in for my flight home, the check in counter staff decided that they would rather not have it as a carry on item, so they provided a cardboard suitcase box. I didn't hold high hopes of ever seeing my steel again - I fully expected an unexplained rattle to show up in the cargo hold; but on arrival, my box showed up on the baggage belt without even a mark on it. I'm betting the baggage handlers got a few surprises along the way! Gerry :-)} London, Canada

Does the motor start very rapidly? If so, the torque when it starts is turning the arbor inside the wheels, knocking them out of alignment. The wheel hubs/washers they put on these things are usually awful pieces of stamped sheet metal. If you have a lathe you can make new dished washers to better support the wheels without crumpling.

I seriously doubt you are doing it when moving the whole unit.

Jon

I fear they wouldn't serve the purpose. Their name is very revealing-------they are intended to stiffen a blade, not make it run at right angles. If the arbor has error, there will be as much compromise in the angle as the bore permits the washer to tilt. It's important for the shoulder to be square, and have full bearing on the flange, which must be parallel---and need not necessarily be a tight fit on the shaft, although a snug fit is desirable to minimize peripheral runout.

Harold

They are also a bit too large. The washers on the grinder are 2.75" in diameter, versus 3.5" for the blade stiffener. The 2.75" washers fit the blotter more or less perfectly. The thickness, 0.25", is OK.

Joe Gwinn