Wheel balancing required?

[ewlsey]

I have a Tatung 8X20 grinder. It takes 8" wheels.

The manual stresses balancing the wheels. I don't have a balance arbor or balancable hub. How important is this today?

 

[adama]

All depends on just how out of balance it is and how picky the machine is to this. My experience with 6x18" capacity 7" wheel grinders it can have a noticeable affect. But more so in a how good a finish do you really want kinda way.

 

[swarf_rat]

I am also curious about this. Yesterday I mounted an 8" wheel and tried the following:

1) Mount wheel, mark position on hub and spindle, run and check for vibration.

2) Loosen wheel, rotate assembly 180 degrees, retighten and check.

3) Loosen wheel, rotate on hub 180 degrees, retighten and check.

4) Remove hub, rotate assembly on spindle 180 degrees, reinstall and check.

When I say check I mean run it up and feel the spindle housing with a "sensitive hand" - I don't have a balancer, trying to decide if it is worth the trouble. There were definite differences, more so between 1 and 2 than the others. My spindle has 0.0002 runout, the new Sopko hub seemed to have 0 runout (it accurately follows the spindle), the Norton wheel has about 0.006 clearance on the hub so between 1 and 2 I am moving the clearance from one side to the other. The difference between the best and worst attempt was no perceptible vibration to just perceptible vibration. I did the experiment because I test ground a piece, tried a couple of different wheels, returned the original wheel and test ground again, but this time got a pattern that looks like vibration, and I could barely feel some. Mounted it the same way I thought.

I remain curious as to why automatically balancing wheel hubs are not available. Ball bearings around a track in the perimeter, this is old technology, perfect balance after a few seconds running.

 

[Glenn Wegman]

1) Mount wheel, mark position on hub and spindle, run and check for vibration.

You need to true the wheel after mounting it.

Some people only purchase one adapter and then change wheels when a different wheel is needed. I prefer to mount a wheel on it's own adapter and it lives there for the rest of it's life. I also true the face and a little ways up the sides of the wheel. Changing wheels on the adapter leads to shorter wheel life through the need for excess truing.

 

[IronReb]

This has prolly been mentioned but just in case...
Before you mount any grinding wheel it is a good idea to stick a hammer handle (wood) thru the hole then lightly tap around the face of the rock with another wood hammer handle.What your looking/listening for is a crisp clear ring,just like tapping on a bell.
If there is a crack in the wheel it will make a thud sound instead of a ring.Been doing this shit for almost 30 years and have only came across one wheel that was cracked.All it takes is that one cracked wheel to ruin a good day.

 

[swarf_rat]

You need to true the wheel after mounting it.

Yes of course. Experiment I was doing was, how much is balance affected by the various sources of slop in the system?

Truing it probably has more effect than the other things, thinking about it this way (assuming uniform density): prior to truing, I have the mass of the wheel 0.003 off the center of rotation due to size tolerance in the hole. After truing, I have only the equivalent mass of the hole 0.003 off center, a reduction of about 97%. I suppose then that most vibration must come from non-uniform density in the wheel.

 

[POAx]

I have performed balancing of my wheels this way: I have turned a washer in aluminum as I i have fasten with "two side addhesive" tape to the wheel. The washer has 24 M4 hole in its periferi. I have turned a mandrel with the same dia as the spindle. I have two grinded bars in water level. I mount the wheel, together with the washer, on my bench grinder. I am dressing the wheel. Then I demount the wheel, with its washer, put it on the mandrel and place it on the water leveled bars. I can then mount short M4 screws in the washers periferi until the wheel can be stopped in all postions. The wheel with its washer, is now balanced and can now be mounted on the grinder. Perform a second dress and you will be very happy of the grinding result.

 

[ewlsey]

So is the conclusion that no one knows?

There seems to be more hear-say, rumors, and wives tales related to grinding than any other area of machining.

 

[CarbideBob]

......
There seems to be more hear-say, rumors, and wives tales related to grinding than any other area of machining.

Welcome to the world of grinding.
Bob

 

[tdmidget]

Before I worried about balance I would make absolutely sure that the machine is supposed to have 8" wheels. On another thread in this forum a member concluded that his machine was an 8" machine. He found that it is 8' on 50 Hz ;ie 3000 rpm. At 60 Hz it is a 7 " machine. Either way balancing is not normally required on wheels of this size.

 

[adama]

Most grinding related stuff is not so much a yes or no answer more of a grey in between or "art". On my Jones and shipman 540 a balanced wheel makes a noticeable improvement to surface finish. 90% of what i grind though realy does not matter surface finish wise hence i don't bother with balancing.

Hence is balancing required, no. But a well balanced wheel can help improve finish when it really matters.

 

[Heavey Metal]

Buy a balancer balance every wheel on its own arbor the payback will be in spindle bearing life

Price a set of bearings

Be thankfull if yours are still quiet

So is the conclusion that no one knows?

There seems to be more hear-say, rumors, and wives tales related to grinding than any other area of machining.

 

[allloutmx]

So is the conclusion that no one knows?

There seems to be more hear-say, rumors, and wives tales related to grinding than any other area of machining.

we balance all of our big wheels on our creep feed and centerless machines but not on our parkers...it would be more relevant to do so on a larger wheel being that the further out you have rotating mass from the spindle, the more it will influence.

I wouldnt worry about it unless you see a problem on your part.
quick tip..when you are done grinding turn the coolant off and let the wheel run so the residual coolant exits the pores of the wheel. if you stop the wheel with coolant in it, it will all be on one side of the wheel when you turn it on next time.

 

[cash]

We have all sizes of wheels and grinders.

The only balancing arbor we have in our shop is on top of a shelf with 30 years of grind mist on it.

I have not balanced a wheel in my life. I have been grinding now for 20 years.

I will say you DO NOT need to balance wheels.

Some here may say you need to, if somebody says this I am not saying they are wrong.

Here is a link to our website and you can see what we do and how much grinding we do. You can get to my youtube page as well from here.

Industrial Knives

I will agree with all the guys here who say grinding is an "art".

 

[adama]

Cash, based on the size of your grinders i would dout they would even vibrate if you cut a stone in half leaving just enough to mount the remainder on the hub. Heck some of your wheel heads probably way more than my whole grinder :-) Gotta be a distinct advantage to the problem there.

 

[Glenn Wegman]

Aren't grinder motors usually dynamic balanced to eliminate vibration that could effect surface finish?

If this is true, how does it differ from wheel imbalance having an effect on surface finish?

Just a question, not an argument.

I have wheels that run smooth with no balance, and I have one 7" wheel that noticeably shakes my Parker surface grinder and leave a terrible finish!

 

[Tyrone Shoelaces]

We have all sizes of wheels and grinders.

The only balancing arbor we have in our shop is on top of a shelf with 30 years of grind mist on it.

I have not balanced a wheel in my life. I have been grinding now for 20 years.

I will say you DO NOT need to balance wheels.

Some here may say you need to, if somebody says this I am not saying they are wrong.

Here is a link to our website and you can see what we do and how much grinding we do. You can get to my youtube page as well from here.

Industrial Knives

I will agree with all the guys here who say grinding is an "art".

If they don't need balancing why do the makers put balance weights on the wheel arbours ?

Regards Tyrone.

 

[sable]

We have all sizes of wheels and grinders.

The only balancing arbor we have in our shop is on top of a shelf with 30 years of grind mist on it.

I have not balanced a wheel in my life. I have been grinding now for 20 years.

I will say you DO NOT need to balance wheels.

Some here may say you need to, if somebody says this I am not saying they are wrong.

Here is a link to our website and you can see what we do and how much grinding we do. You can get to my youtube page as well from here.

Industrial Knives

I will agree with all the guys here who say grinding is an "art".

I would have guessed that if anyone ballanced his wheels it would be you Cash!

I don't do that much grinding but I haven't ballanced a wheel either. I think it is usually only needed for very fine finishes but I have learnt on PM that there are wheels around that are way off balance ,perhaps it depends what make you use ,there are even wheels around now with no name on that come from who knows where .
I was told that wheels always used to need ballancing (that's why the weights are there) but the manufacturing processes have improved.

 

[cash]

I think the weights on the arbors is something that has just been done for a long time. These could have been needed when the quality of wheels was not so good and they were needed.

All of our arbors have weights on them.

Rusted in place from day one.

Back in the late 90's we rebuilt some machines and the thing then was to put on a SBS balance system or Marposs wheel balancer. This had a sensor on the machine and then a unit not he front of the spindle which had weights in it which would move to "balance" the wheel.

We had a total of 4 machines with these. After time they went bad and it was too $$$$ to replace the parts. When we stopped using them we saw no difference in finish.

 

[tdmidget]

The linear ball bearing (also called ball bushing or shaft guiding) consists of a polymeric cage with raceway segments made of hardened steel to guide the ball sets within the complete system. Recirculating balls provide unlimited stroke at low friction movement.
SKF linear ball bearings are available in two design ranges: the compact 1 series (LBBR) and the heavy duty 3 series (LBC) designed according to ISO 10285.
The wide product range includes bearings, housings, shafts and additional accessories that can be used to build economic and simple linear guiding systems for a wide variety of applications. Hengli linear ball bearings and units for shaft diameter 6 mm and larger are factory pre-lubricated. Due to the applied amount of grease and the use of SKF double-lip seals (2LS), many applications will not require relubrication because in these cases the theoretical relubrication interval exceeds the bearing life. These linear bearings are lubricated with the high-performance grease LGEP2.

Well I have all my balancing questions answered And my daily dose of Spam.