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For those of you with High Speed Bench Grinders

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I have a JET 3450 RPM 8" Bench Grinder. This thing vibrates like crazy with new Aluminum Oxide wheels (Norton & others).

The wheels definitely appear to have some wobble, most notably at slow speed while shutting off, but is this common?

I have used the Oneway balancing kit but it's pretty useless.
 
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If the wheels wobble, probably want to see if you can spot where - when not running, check the motor shaft runout (and see if you can wobble the shaft which would mean bearings/bushings/motor housing has wear or play) , then put wheels on and see how snugly they fit to the shaft itself (and also check the collars the wheels sit on - if they are cracked, bent, corroded or not square, and not replaceable, time for new grinder.. if they are removable, check there's no debris between hub and collar cocking them to one side) , check runout on the collars, check wheels themselves for flatness where they contact the collars, and if everything else checks out true, then maybe just have to dress the sides of the wheels (if they don't run true to their hubs) I have had to (at considerable risk, though) dress the sides of cheap grinding wheels to get them to run true, but you gotta be really really careful, and very patient and steady with a very very light touch of dressing brick/wheel/tool to the side of wheel.. But bear in mind doing so (or any grinding on the side of wheel in fact) you will risk exploding grinding wheel syndrome... But, if you find runout or wobble in the shaft that you can't correct with adjustment, best bet is to get a new grinder.. I would not advise trying to shim up only one portion (shims can throw out at speed, no matter how tight you get the nut, then your wheel can explode)
 
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I have a slow speed grinder w CBN wheels. I'd like to have a high speed machine with oxide wheels for rough grinding and/ or shaping.
 
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Tom, I still use my high speed grinder for the reasons you state. I get a little OCD with this kind of thing, so as they say, your milage may vary...
The wheel, hub and shaft get marked with a sharpie to keep that part of the equation constant. The side to side wobble is taken out first. Masking tape shims between the hub and the wheel (not between hub and shaft face) on the motor side. This is a pain. it means marking the high wobble on the outside edge (not the face), taking the wheel off the shaft, loosening the hub, inserting a piece of tape 180° from the outside mark and repeating till satisfied. The grinder does not need to be turned on during this process, just rotated by hand to mark the high spot (outside). The hub should be tight but not vice and a pipe wrench tight. With the wobble fixed, the face is trued, I like Don Geiger's wheel dresser as it rides on the edge of the platform keeping the wheel concentric. ( https://www.geigerssolutions.com/Tru-N-Dress-Models.html ) Once the wheel is trued, the balancing begins. By the time I bought my slow speed grinder, I had lost the original OneWay balancer and so bought the one that uses the bearings. The grease in the bearings caused too much resistance so I cleaned that out with thinner and compressed air. Balancing was still fiddly, but much better/easier with no grease. Two things that helped the most was the wheel dresser and cleaning out the grease. I've never bought a wheel that didn't need some help, altho some were better than others. A smooth running grinder is a good thing...

For those not familiar, the OneWay balancing system uses a two part hub that screws together sandwiching the wheel in-between taking the place of the normal two washer system. Balancing is accomplished with two positionable counter weights on the hub with the wheel hanging on some grease filled bearings. Heavy settles to the bottom, weights adjusted, wash rinse repeat...
 
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Tom, I still use my high speed grinder for the reasons you state. I get a little OCD with this kind of thing, so as they say, your milage may vary...
The wheel, hub and shaft get marked with a sharpie to keep that part of the equation constant. The side to side wobble is taken out first. Masking tape shims between the hub and the wheel (not between hub and shaft face) on the motor side. This is a pain. it means marking the high wobble on the outside edge (not the face), taking the wheel off the shaft, loosening the hub, inserting a piece of tape 180° from the outside mark and repeating till satisfied. The grinder does not need to be turned on during this process, just rotated by hand to mark the high spot (outside). The hub should be tight but not vice and a pipe wrench tight. With the wobble fixed, the face is trued, I like Don Geiger's wheel dresser as it rides on the edge of the platform keeping the wheel concentric. ( https://www.geigerssolutions.com/Tru-N-Dress-Models.html ) Once the wheel is trued, the balancing begins. By the time I bought my slow speed grinder, I had lost the original OneWay balancer and so bought the one that uses the bearings. The grease in the bearings caused too much resistance so I cleaned that out with thinner and compressed air. Balancing was still fiddly, but much better/easier with no grease. Two things that helped the most was the wheel dresser and cleaning out the grease. I've never bought a wheel that didn't need some help, altho some were better than others. A smooth running grinder is a good thing...

For those not familiar, the OneWay balancing system uses a two part hub that screws together sandwiching the wheel in-between taking the place of the normal two washer system. Balancing is accomplished with two positionable counter weights on the hub with the wheel hanging on some grease filled bearings. Heavy settles to the bottom, weights adjusted, wash rinse repeat...
Thanks, I have Geiger's dresser and it's great.
Did you suggest dressing the wheel before attempting the tape/balancing act?
 
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If dressing the wheel hasn't helped up till now, probably not. Marking the shaft, hub or washers, and the wheel, help keep everything consistent.
I'm using the Oneway balancing hubs, so I shim between the hub and the wheel on the motor side to fix side to side wobble, then true the wheel, then balance.
I suppose, if the grinder was really bouncy, you might have to true, balance, true, balance, but I haven't had to do that. The first balancer used a trough and axle and the heavy side natural sunk or rolled to the bottom, the new style with the bearing is not as sensitive, but as I said earlier, cleaning out the grease helps a lot.
 

hockenbery

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Thanks, I have Geiger's dresser and it's great.
Did you suggest dressing the wheel before attempting the tape/balancing act?
Don Ginger does a terrific demo on balancing new wheels.
like @Clifton C describes. Don uses 1//2” adhesive backed dots. he sticks them on the wheel under the edge of the washers On both side of the wheel on opposite side of the shaft. these push the wheel into perpendicular with the shaft.
if one dot on each side doesn’t do it add another dot on top.
keep adding dots until it run true. I should not are more than 3 or 4 dots in the stack on each side.

touching a pencil lightly to the outside of the wheel will show the spot that needs to move toward the motor.

true the wheel After alignment.
 
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Lance Mirrer

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Ken Rizza of Woodturners Wonders has balancing spherical washers which fixed my wobble.

 
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Well, the problem is most likely in your wheels. If they have plastic bushings in them, get rid of those and find some metal ones. If you have a cast wheel with a bored hole in them, first spin the wheel by hand and see how much wobble there is, and specifically side to side wobble. This can be trued up some what, but if you ever take them off, you have to mark where they go back on because, like bowls, they never remount exactly the same way...

The washers from Ken make up for the nuts on the grinders. They are not precision made, and can be angled rather than dead square and/or flat. I haven't tried this yet, but would think that you could chuck them up and turn them down flat with a good scraper. They are a softer metal and will easily turn with M2HSS. Do take very light cuts. I would turn one side, then flip over and turn the other.

Best alternative is to get rid of those wheels and keep them only for using for non hardened metals and get yourself one or two CBN wheels, a 180 will do almost every thing you need, and a 600 is great for skews and gouges if you are needing a particularly fine finish cut. The cost of the CBN wheels is a a bit much, but if you get the Oneway balancing system, and the Geiger truing up thing, it is around the same cost, and you don't ever have to balance or true up your wheels ever again.

robo hippy
 
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Like Tom, I kept my high speed grinder w/course A/O wheels for shaping or anything I didn't want to take to my CBN wheels. By the time I joined the herd (odie:)) and jumped on the CBN bandwagon, I already had the high speed, slow speed, balancer, wheel dresser and a bunch of A/O wheels. Selling wouldn't have gotten even half a tank of gas, besides, more tools is more better...
 
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Don Ginger does a terrific demo on balancing new wheels.
like @Clifton C describes. Don uses 1//2” adhesive backed dots. he sticks them on the wheel under the edge of the washers On both side of the wheel on opposite side of the shaft. these push the wheel into perpendicular with the shaft.
if one dot on each side doesn’t do it add another dot on top.
keep adding dots until it run true. I should not are more than 3 or 4 dots in the stack on each side.

touching a pencil lightly to the outside of the wheel will show the spot that needs to move toward the motor.

true the wheel After alignment.
Hockenbery, can you, or anyone else, find a link to that Geiger demo you refereed to? I looked on his site and searched Youtube but can't find it.
Thanks
 

hockenbery

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Hockenbery, can you, or anyone else, find a link to that Geiger demo you refereed to? I looked on his site and searched Youtube but can't find it.
Thanks
I’m not aware of a video Except for club libraries of the club demos.
Don lives about 2 hours away and does demos for two clubs we go to about every other year.
this has some photos showing the process,
 
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Jul 10, 2017
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Windermere, British Columbia
I have a JET 3450 RPM 8" Bench Grinder. This thing vibrates like crazy with new Aluminum Oxide wheels (Norton & others).

The wheels definitely appear to have some wobble, most notably at slow speed while shutting off, but is this common?

I have used the Oneway balancing kit but it's pretty useless.
I tried the Oneway balancer and thought the same. Then a friend showed me how to use it properly. What a difference.
 
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