Is it possible for just 1 side of the actual grinder to be "bad"?

[Joshua Dinerstein]

I am sorry if I sound like a broken record about sharpening I just trying to figure this whole thing out. I have a slow speed grinder from Woodcraft. A few weeks ago it seemed to go bad. I figured it was the wheels and so I began looking for solutions.

Recently I put a new white Norton 60 grit wheel onto the right hand side using a OneWay balancing system. It spins so true it is amazing. I had a bad wheel which Hartville tool was quite good in replacing for me quickly. It came today so of course I wasted no time coming home from work getting it balanced, which was a chore with this wheel?!!? where the last one was EASY, and then onto the grinder. I spun it up and it wobbled so badly I could actually hear it shaking the stand which has a 60lbs bag of sand on it holding it down solid.

I stopped it and spun it by hand and there as a very slight but visible wobble. I turned it back and then off and there was a much more pronounced wobble as it slowed down after having been back up to full speed.

I was stand out there in the shop somewhat dumb-founded when I stopped and thought, I wonder if something went the way of the dodo in the grinder itself. I mean it had been better than it now is just a month or so ago. And the wheel that was on it had really weird skipping sounds when I tried to use it.

I don't know much about grinders but I think there would have to be a bearing in there with probably one on each side. And it would seem any bearing can go bad though with how little use a grinder used only for sharpening turning tools gets one would think they wouldn't wear out very fast.

So I thought I would ask. Anyone have thoughts? Or experienced anything like this?

Note: I am beginning to think I really am cursed. Seems everything i touch out there in the shop either comes bad or goes bad. :)

Thanks,
Joshua

[Ken Fitzgerald]

Joshua,

Recheck the last thing you did. If that's okay, recheck the other side.

There is no magic to a grinder.

If I read this correctly, it improved until you balanced and installed the 2nd new wheel. IF that is the case....either the new wheel has a problem, something isn't right with the way it balanced OR...the other wheel has become out of balanced.

Nothing magic ....1 shaft....2 mechanical loads....one on each end. While a bearing might be the problem, I doubt it as I would expect a bearing to seize up, make a grinding noise......chatter.....get hot....not just cause wobble/vibration.

I'd recheck everything you have done....1 thing at a time.........


Try replacing the latest wheel with the old one you took off.

[Kyle Iwamoto]

Take both wheels off and turn the grinder on. See if the shaft spins true. If you got a dial indicator, use that to see if the shaft is true. There is nothing other than the shaft to a grinder.

Dumb question time. Is the hole in the wheel the right size for the shaft? They come with adapters sometimes.

If it runs true, swap the wheels. See if it is the wheels or something stranger than fiction.

I can't see something vibrating that badly. Must be bent shaft or wheels not made right.

[Faust M. Ruggiero]

Josh,
I've been waiting to see what would happen to your wheel balance without the type wheel dresser that would assure a round wheel. The Oneway Balancer is great but if you dress the wheel with a hand held diamond dresser, the kind shaped like a "T", you may be dressing the wheel out of round. That's why so many people talk about the Geiger or Oneway wheel dressers. Check your balance on the bad wheel. If it is no longer balanced, either the Oneway insert moved or you may have spoiled the balance with the dressing.
I would tell you to swap the wheels but you would have to swap the Oneway wheel inserts and re balance first. That may only temporarily fix the issue.
I believe you need the one last grinder toy.

[Thom Sturgill]

You said you used the OneWay balancer, so that eliminates the cheap plastic adapters. Swap the wheels. If the same WHEEL has problems, it is the wheel, if the same SIDE, then it is the grinder that is the problem. I suspect that the wheel is out of true (warped or oval) and will vibrate at speed even if statically balanced. It is possible to have a bent arbor and your gauge to check runout will verify if that is so, but I have to remember a statement by a vendor (Joel) that stated he had never seen a bad grinder, but had seen quite a number of bad wheels.

[Don Geiger]

The wheels must be made concentric to the axle, as they are mounted, or your tools will most likely bounce.

You can counter balance eccetricities in the wheels using weights which, if properly placed, will reduce vibration in your grinder. This will not eliminate tools from bouncing. (or "chattering") until the eccentricities are corrected.

[Joshua Dinerstein]

Hummm. OK. I got rushed to bad last night by a wife who was tired of waiting to turn out the light. So I didn't quite explain everything as well as I wanted too.

I have the OneWay bushing system that balances things. Sadly that system makes things 1-side-only. So I am not sure how I could try the right hand wheel on the left hand and vice versa. I really don't want to mess up the smoothness of the right hand side.

Until a month or more ago the grinder worked pretty well. Then it started to do this terrible bounce with the tools. I had a fellow creeker and local friend come over and check things out and verify that it was bouncing and "ticking" against the dresser the way that I thought. Ian was shocked at how bad it was. Which started the search for a truly good setup.

So from Hartville tool on a pretty good sale came 2 new wheels and the balancing system. By luck of the draw I did the right wheel first with a good new white wheel and it is amazingly true. In every direction. I am getting sharpening like I have never seen from it and I still haven't placed my order for the Geiger dresser yet.

The wheel, to keep this long saga brief, for the left side was broken in the box and needed replacing. In the interim I put the old 120 grit wheel that it came with back on. Wobble. I put a 60 grit norton "red" wheel I bought locally that was marked for "metal" on it and it wobbled tho less than this and when it came yesterday I put the replacement 60 grit wheel on and it wobbled as bad as the original 120 grit wheel.

Now the original wheel had been running ok, even pretty good. Until some event happened. I have no idea what the event was... I used it once and it was as good as always. (I say that because it was nothing like the newly balanced new wheel, but was manageable.) Then I noticed it all of a sudden on the next round it went from smooth to bouncing like mad. Literally I turned it on and let it come up to speed and then turned it off and let is spin down and held my old standard t-square dresser up near it instead of hearing it dress all the way around I hear tick-tick-tick.

So back to the new wheel. I had held a reference point up near it the inner edge on the face of the wheel and manually rotated the wheel. I could see a slight change in difference as that inner surface came closer and then got further away. It was a disappointment as the other one runs so well but I figured I could work around it. Then I turned it on and let it come up to speed to some serious vibration. I fussed for a few minutes trying to figure this thing out and finally I turned it off while using a reference point that didn't touch but was just close. The wobble as it powered down was seriously more pronounced. It seemed to be at least 10x worse in left to right travel on the face of the wheel. After it had come to a complete stop I re-spun it by hand to see if it had actually shifted position or simple gotten into a much worse state. Nothing had changed. It still wobbled but at the much smaller shift I had seen before powering it on. So it seems to have something to do with a greater speed than I could spin it by hand or having the motor turned on.

I have a high-speed 8" grinder from HF out in the garage that I use for rough grinder metal for stuff just around the house etc... I got it before I got into turning. I have never really care how true it was as the applications I use it for that doesn't matter. But I got to thinking last night that I could use it to test out these wheels. See if they run true on the left hand side of that grinder. But I I will have to be careful to check it thoroughly first to see if that thing runs true in the first place.


Last question for this morning I guess is this, is it safe to run a grinder with only 1 wheel on it? Because I am ready to just use the right hand wheel that is working so well and ignore the left side altogether so that I can at least go and do some turning instead of continuing to fuss with all of this stuff.

Thanks for all the help!
Joshua

[Dave Ogren]

For more than 40 years I have been running a 6" high speed grinder with a wheel on one end and a wire brush on the other. Good Luck.

Dave

[Mike Ramsey]

Joshua,
Check the inside washer on that side of your grinder, lot of times it's
the washer that's out of round causing wobble..

[Harvey Schneider]

Joshua,
For rotating objects there is a phenomenon that is known as critical speed.
A slowly rotating wheel spins around its geometric center. That is the center of rotation based on physical dimensions.
At high speeds the wheel rotates around its mass center. The mass center may differ from the geometric center because of imbalance irregular shape or non uniform density.
The critical speed is the speed at which the forces acting on the spinning wheel move it from the geometric center to the mass center. At that speed the wheel can actually hop back and forth between the two modes of rotation, and appears to be vibrating much worse than in either to the two stable states. Prolonged operation at critical speed can be damaging, but that is not what you are seeing here. The grinder vibrates worse as it passes through the critical speed.
The Oneway balancing system is a static balance system and while it does a very good job it cannot correct all imbalances. A dynamic balance system, where the wheel is spun to determine the imbalances (like automotive wheel balancing), would be required for that.
The long and short of it is that the change in vibration you see as the grinder speeds up or slows down isn't important.
Just a note on a related subject. The same thing happens to a chunk of wood on the lathe. The wood is stable at both higher and lower speed, but vibrates severely at the critical speed. Operation at or close to critical speed can be damaging to the lathe bearings. It is better to work below the critical speed, because as you remove wood and reduce the mass the critical speed increases.
This was probably more than you wanted to know, but understanding is better than knowing.
Harvey

[Reed Gray]

The only way to be sure it isn't the grinder is to get a Baldor.

As some one once said, "Buy the best tool, and cry once. Buy the cheap tool, and cry every time you use it."

I don't even have to bolt it to my work bench.

robo hippy

[Leo Van Der Loo]

I am sorry if I sound like a broken record about sharpening I just trying to figure this whole thing out. I have a slow speed grinder from Woodcraft. A few weeks ago it seemed to go bad. I figured it was the wheels and so I began looking for solutions.

Recently I put a new white Norton 60 grit wheel onto the right hand side using a OneWay balancing system. It spins so true it is amazing. I had a bad wheel which Hartville tool was quite good in replacing for me quickly. It came today so of course I wasted no time coming home from work getting it balanced, which was a chore with this wheel?!!? where the last one was EASY, and then onto the grinder. I spun it up and it wobbled so badly I could actually hear it shaking the stand which has a 60lbs bag of sand on it holding it down solid.

I stopped it and spun it by hand and there as a very slight but visible wobble. I turned it back and then off and there was a much more pronounced wobble as it slowed down after having been back up to full speed.

I was stand out there in the shop somewhat dumb-founded when I stopped and thought, I wonder if something went the way of the dodo in the grinder itself. I mean it had been better than it now is just a month or so ago. And the wheel that was on it had really weird skipping sounds when I tried to use it.

I don't know much about grinders but I think there would have to be a bearing in there with probably one on each side. And it would seem any bearing can go bad though with how little use a grinder used only for sharpening turning tools gets one would think they wouldn't wear out very fast.

So I thought I would ask. Anyone have thoughts? Or experienced anything like this?

Note: I am beginning to think I really am cursed. Seems everything i touch out there in the shop either comes bad or goes bad. :)

Thanks,
Joshua

you can balance a wheel but that doesn't make it run true, like when there's something between the wheel and the disks that hold the wheel, and dirt folded paper etc can make the wheel not turn true.
Also if the wheel is not round (circular) you can balance it (statically), this would have your grinder still vibrating as it is turning.
As you say it is visibly wobbling, I think you do know what's wrong, so rectify that first, you don't have to look at something else being wrong, does the other side wobble or the wheel you took off ??
So first get the wheel to turn without a left to right motion, then make it round and then balance it, it is very easy, just do one at the time

[Joshua Dinerstein]

The only way to be sure it isn't the grinder is to get a Baldor.

As some one once said, "Buy the best tool, and cry once. Buy the cheap tool, and cry every time you use it."

I don't even have to bolt it to my work bench.

robo hippy
OK so I looked. I found them ranging from $800 to $2,800. Admittedly the 2800 dollar one was a 14" baldor. But wow. So where does one go about getting Baldor grinder? The places I found them were talking about them not actually selling them.

Joshua

[Roger Chandler]

Joshua,

A wobble can present itself because of the washer on the inside of the wheel not seating correctly on the arbor shaft, and it can also wobble because of a small high spot on the wheel itself near the hole where the washer rests against the wheel. You can eye the washer and wheel to see if it is out of plane with the use of a reliable straight edge. Of course you have to remove the wheel from the grinder.

Also, wobble can present itself, and likely will if you use the blue plastic bushings that come with the Norton wheels. If I recall, [I may be incorrect] I thought it was you [maybe someone else] who got the drill bushings from McMaster-Carr, for the wheels. They will dramatically help the wobble issue.

Also, sometimes repositioning the wheel a few times can minimize the wobble to get the best position on the arbor, then true your wheel from there.

I hope this helps you!

[Reed Gray]

Joshua,
Check out Kaman Industrial Tech. They are all over the country, and have the best price I found. Mine was less than $700 about 5 years ago.

The one is Salt Lake is 810-975-2000. I get all bearings and motor type things there. Lucky to have one about a mile from my house.

robo hippy

[Faust M. Ruggiero]

Josh has the Oneway Balance system. The system works with wheels that have a 1" bore. The bushings are replaced by Oneway's proprietary two part bushings that thread together. Left hand thread for the left wheel and right hand for the right wheel. They match the wheel nuts on the grinder. In order to swap wheels, you must swap bushings. Since movable weights on the bushings serve to balance the wheels, swapping the bushings will force Josh to re balance both wheels. Assuming one wheel is not concentric to the shaft, as Don pointed out, you can still balance the wheel but the tool will still bounce. Josh's first job is to be sure both wheels are concentric. You will need a wheel dresser like Don's to assure yourself they are correct. After making sure they are "round" re balance them. If they begin to bounce after some use, just dress them and the balance will remain intact.
By the way, did you replace your grinder's inside washers with the machined washers sent by Oneway? I believe that is where they live as versus between the nut and the wheel.
If after all this expense the wheel still vibrates, find someone you don't like and give them the whole darn thing for a present and start again. Keep the Oneway and the Geiger. Good luck!!
butch

[Jon Lanier]

If you turn the other half the grinder inside out you should be good to go. :rolleyes:

[Gary Herrmann]

I've got a woodcraft grinder and a 15 year old Baldor pedestal grinder I picked up for $200. There's no comparison. The Baldor is lightyears better.

[Joshua Dinerstein]

By the way, did you replace your grinder's inside washers with the machined washers sent by Oneway? I believe that is where they live as versus between the nut and the wheel.


I did replace them. I had to switch to them to keep the wheel centered. I checked the washer for flatness and it is amazingly flat. They are machined rather than stamped and you can really tell.

I just think it is so weird. That the one side trued up like mad and runs so clean. And that the other sides doesn't. So I went out and got a new norton 3x wheel from the local woodcraft. I wanted to see what it would do. It was more expensive but I don't know that it is better.

I also went out into the garage and got out a "new" grinder. Not a baldor but something I already owned. It is a high speed HarborFreight. But it should help to prove what is going on/going wrong.

I also got out dial indicator and magnetic base and I am going to see if I can't detect what is really going on.

One way or another I am going to get this working. :) Or die trying.

Joshua

[Thom Sturgill]

I don'y have the OneWay balancer, so I didn't know that they included a two part threaded adapter. I still say swap the wheels, just don't power it up. Rotate by hand and see if there is still wobble. You indicated that it was visible..,.

[Prashun Patel]

I'm inclined to think of Occam's Razor here: The simplest explanation is usually the right one.

True sharpening stones are brittle, irregular off the shelf, and can suffer different densities.

I had a tough time getting my Norton 60 to balance. Dressing reduced most of the wobble. But in the end, it is my belief that these wheels are just persnickety.

I think that's why mfg's ship grinders with those tool-killing stock wheels. They survive transport and collisions better than the friable types.

To know for sure, swap your wheels spindle for spindle, and also re-install your OLD wheel on each spindle. That was enough to convince me that my issue was the wheels and not the grinder (for now, at least - I ain't no expert).

[Reed Gray]

Oh, yea, the arbor on the Baldor is 3/4 inch. Part of why it is more stable.

Comparing the Woodcraft grinder to the Baldor is like comparing a mini lathe to a PM/Oneway/Robust. Huge step up.

robo hippy

[George Clark]

Joshua,

Before springing for a Baldor, I'd try a few other ideas. First remove both wheels and power up the grinder. If it's smooth then the grinder is probably not the problem. These next steps were suggested by Don Geiger. They worked for me.

1. Replace the plastic bushings with drill bushings available from McMaster-Carr.

2. Eliminate any side to side wobble by shiming with paper shims. Notebook hole repairs or small avery labels work well. This is a trial and error process.

3. True the circumference. This is a lot easier to accomplish, IMO, with a tool that indexes off the tool rest or the Oneway system than with a handheld tool.

George

[Joshua Dinerstein]

Humm. Well I think I might have figured it out. I got out my dial indicator tonight and took off the left wheel.

I set it to measure the shaft and it was... OK. Had a small divot out near the end but ran pretty true all things considered.

Then I went down to where the wheel will seat on the arbor shaft. I tested it first on the outside edge. Wow. It swings like 5 to 8 mils. Wow. I was surprised to see it swing that much. Then I shift things to test the very inside of that same ring on the arbor that it mounts against. I was again shocked to see how true it ran. There was as little swing at I have seen in the past when measuring my 3520b's spindle.

So I took a good look at that outter rim and it is hard to see if it was machined badly or if it has gotten damaged by something I did when I have been working thru all of this. But with it off I can't see how I can get a wheel to run well. So I have to come up with a way to true it up. I did this before with the spindle on a lathe I had but I could slow that down. While that worked fantastically, I am not sure if it will work quite as well on the grinder as it did then.

Anyway, I think I might be onto something here.

Joshua