Slow Speed Grinder Problems

[Gene Michael]

My wife got me one of the Woodcraft slow speed 8" grinder/Wolverine jig combos for my birthday. The wheels on the first grinder were seriously out of round and wobbly. Exchanged it for # 2, which they were supposed to check before shipping. #2 had better wheels, but looked as though it had been used in a metal shop. The grinder had black marks and scrapes on it and the wheels had black stains on them. Additionally, the base was warped. Exchanged it for #3, which came in today. This one was supposed to have been checked out by their top quality guy. It vibrates badly, so I figure I'll spend some time seeing if rotating the wheels on the shaft and dressing them will get rid of this. What really worries me its the wheels come to a stop pretty quickly when I turn the power off. When I turn them by hand, they have more resistance than grinders 1 and 2. Has anyone else had similar problems from this grinder and is that resistance to turning something that should work out with use, or does is sound more like bad bearings? Before I call Woodcraft again, I really need some feedback. Thanks in advance for your comments and suggestions.

[Ken Fitzgerald]

Gene,

I have one of those grinders.

I had a bad vibration in mine. It turned out that one of the nuts that hold the wheels to the grinder had a significant problem. The hole and the thread in the defective nut were not perpendicular to the face of the nut. When tightened, only about 15-20% of the face of the nut made contact with the retaining washer. As a result, the wheel flopped/wobbled when it was spinning. I was able to buy a replacement nut at a local Ace hardware store. Then after dressing the wheel and making it perfectly round, the grinder has functioned well for nearly 3 years now.

You might try turning the grinder on and letting it run for 10-15 minutes to see if the bearings will wear in and then the spin down time increases.

Good luck!

[Gene Michael]

Ken, thanks for the advice. Spent most of the day bushhogging and realigning the table saw, but got the grinder mounted and played with the wheel balance a little. The nuts were OK - turned the wheels to different positions with no effect. Ran it for several minutes, but will set up the wheel dressing jig Tuesday and give it a longer workout. Hopefully this:) will help with the vibration and the bearings.

[doug young]

Ken,
Just a question. I have the same grinder, same wobble(threw the receipt away) and can't tell what is causing the wobble(i'll try a different nut) but here is the question. If i am able to dress the wheel so that it is round and true, will a little wobble side to side(1/16"-1/8") affect sharpening the tools?
thanks ahead of time for the response, doug

[Ken Fitzgerald]

It will effect the grind. You will probably have a hard time getting a flat surface on the wheel if it is wobbling and changing it's position.

If you remove the cover over the wheel, and shine a light down along the inside surface of the nut, you should be able to see the face of the nut making contact with the washer. Rotate the wheel while watching the inside surface of the nut. Then try wiggling the wheel in the axis of the shaft. It should not wiggle even if the hole in the wheel is too big. The nut tightened against the retaining washer should prevent that from happening. If you find it wiggles, you have isolated the cause.