How I Static Balance a Surface Grinder Wheel
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- Опубликовано: 23 июл 2024
- I show you how I static balance a surface grinder wheel. This could also be applied to a bench grinder wheels.
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Thanks Randy, interesting topic and take on balancing, enjoyed!
Thank you Stefan. Touchy subject here walking a thin line.
I had a balancer like yours to balance my crankshaft grinding wheels. It was a little taller as the wheels were about 24" in diameter. The hub had threaded holes around it that we could screw lead weights or washers to balance. Once the wheel was rough balanced it had to be mounted on the grinder, dressed, and then final balanced.
Thanks Steven. This will do dia. to 24".
Hey Randy,
one thing i would like to point out here:
not always is a grinding pattern attributable to an imbalance situation. the grinder i use at work has a similar arbor with the grooves and weights.
when i reground the working table of the Deckel pantograph mill i was seeing a scalloped finish in parts of the ground surface. after many trials i narrowed it down to the outer arbor bearing starting to go bad. now whenever i have a small job to do, i have to dress the wheel each time i use the machine. once the bearings have picked up enough oil, and are running up to speed i don't shut off the head until the job is done. this does present a safety issue but it is how i have come to deal with that shortcoming of the machine.
if for some reason you're seeing a repeat in grinding patterns it may be time to inspect the arbor bearings.
cheers
mike
Looks like a worthwhile process Randy. Just wish I had a surface grinder!!
Thanks Chris, even a small one is great.
Thanks Randy, I have never balanced a grinding wheel , Yet. I figured it was done similar to this. I have a smaller version of your spin balance unit. I used it for airplane props on large RC models. Very good video and Thanks for sharing
Thanks Steve. Even bench grinder wheel benifit from balancing. Especially in the larger sizes, 10-12" wheels.
It's a great idea to balance your wheels. It helps the bearings on the machines they go, and the surfaces those machines rest on last much longer. Helps accuracy too in surface-grinding applications.
Good info. If I ever get some time I will start on restoring my B&S 6x12.
Well worth the effort. Thanks Tom.
Neat video Randy!
Thanks Danny.
very well explained mate. there was an article in model engineers workshop about using special custom made washers to balance bench grinder wheels.
Thank you Jason.
Good balancing lesson, thanks.
Thanks Harold.
Randy very informative video .
Thank you Bob.
Good lesson on balancing those wheels Randy. I think I have to buy more hubs for my grinder. I get tired of changing from wheel to wheel.
Take Care,
Reid
Thanks Reid. Yes more hubs, 10 at least, well worth it.
Hi Randy another great video.
Bill from Seattle.
Thank you Bill fro stopping by.
Very slick setup you have Randy. I just priced out a set of those balancing wheels and stands at McMaster Carr - more than $1K
Ebay. Made a crazy low offer on a long time listing, they took it. Thanks John.
Maybe someday I'll finally join the surface grinder club. For now, I'll have to be content watching you guys! Hope you and the family are well, sir.
Best wishes,
Tom Z
Thanks Tom. Someday. You have more space now. All good, thank you for asking. I hope you are getting your house done.
Good discussion on wheel balancing, still need o find myself some extra hubs for installing grinding wheels without the ordeal of mounting and dismounting... ;)
If you see some 1 1/4" standard hubs go by that you won't need let me know...
I will keep my eye out. Thanks Pierre.
Interesting video Randy, although I'm not comfortable drilling the wheel though but I understand the need. I only have a few bench grinders for sharpening tool steel and jamming lumps of steel into.Wouldn't a steel disc work for balancing, or better an eccentric disc which could be rotated until balanced then glued. Thanks for the video Peter
Thanks PGS. Yes the drilling has to be done with care, I have never had a failure. But I have been thinking of some special washer.
Thanks for sharing
Thanks Mike.
I made a homemade balancing jig and use a piece of 5/8 inch stock as an axle to balance the wheel.Will a loose fit on the axle significantly affect the accuracy of the balancing? Thanks
Shouldn't. As long as the friction is minimal.
Thanks
As Paul Mathews posted, I have also read here and there that balancing good quality 7" surface grinder wheels is not worth the effort. My question to you, Randy, and others, is whether you get noticeably better surface finishes on your work after balancing the wheels. If so, is it all the time or part of the time? I have not done it yet, but I think it is well worth taking out any radial gap between wheel and hub over .001" by shimming it. I am a raw beginner at surface grinding and need good and useful advice. Surface grinders are pretty simple machines, but have fairly large learning curves in my limited experience so far.
This is actually a pretty nifty design for a balancer. The large, opposed wheels make it easy to see the ramping acceleration and deceleration of an unbalanced wheel. You'd almost think it was intentional, eh? lol
What they use in small auto-shops to balance car wheels is pretty similar, although big dealer shops use spindle-mounted, computer-assisted devices that measure the balance of the wheel down to 1000ths of a mm.
On another note, it's pretty strange that the heavy section of that black wheel is right beside the section with a chunk missing out of it. You'd think that part of the wheel would be lighter than the rest of it.
The balance works great very sensitive. The chip in the black wheel was actually very small so probably very little effect on the balance. I think most of the balance issues are concentric and a matter of the consistency of the density of the wheel. Thanks for the great comments.
I may have missed it, due to some distractions while viewing, but do you put all your balance holes on the same side of the stone?
Usually same side.
Hey, just wondering where you got the balancer from? Looks like the gromax one what are your thoughts on it?
Found it on ebay, dirt cheap, got lucky. They are an offshore brand, don't know anything abut them.
Oh nice, yeah been looking around found one for $299 USD. Hopefully I find one used for a steal!
You could fit the hub, try balance and then, using the play in bore, move the hub to opposite side before you go any further with balancing or truing.
Thanks Chris, yes it is worth it to try to center the hub, even with small shims.
Or, just try it to one side and then the other and see if it makes any difference at all then you ave a basis of knowledge to work from.
Randy, unless I missed it, you haven't mentioned the need to level your device. I once read that this type of roller device is not as critical as the "parallel bars" type, for leveling? Please comment and also, do you ever mess with balancing 1/4" wheels (with brass washers, etc)?
Thanks for your informative videos - very much appreciated. Mike
This type not nearly critical. Parallel bar type absolutely critical. No I do not on a 1/4" wheel. Thanks Mike.
Great tip! Can't wait to try on my crappy, chinese cheap bench grinder now! I will invest in a quality grinding wheel first, since i suspect the one I have was chiseled out of sandstone. So much play on the hub, I'm almost afraid to use it!
Thanks Erling. Careful now.
I will! ;)
Are those arbors commercially available? This is a time-consuming but accurate procedure. Thanks for the demo.
Thank you Jeffery. I think so, I made my own.
Nice apparatus I also drill my wheels for balancing but I also use an arbor and my lathe bed ways seem to work just fine (poor man version)
Thanks Scott. The ways will work, still must be level.
Hi Randy,
What type of wheel is the Black Norton?
Steve
Norton 37C46-JVK Silicon Carbide, Recmd. by Robin for Cast Iron. Thanks Steve.
That's what I thought it was. I never used one before but read Silicon Carbide was good for Cast iron. I read it was good for Titanium too. Are you going to do a video using it? I would like to see how well it works.
Steve
Seems like everybody with a surface grinder wants more hubs, but they don't *look* crazy complicated. Is there something about them that an ordinary guy couldn't reasonably make them?
Thanks for showing your process, I've got a better idea how that way works now!
Thanks Somebody, The regular hubs are about $50.00 new. Not to difficult to make. The purchased ones are heat treated and ground. The ones with balance weights are about twice as much, may be worth making one of those.
Randy, I challenge your analysis. Once you true the wheel, provided that the density of the wheel material is uniform, remaining asymmetry is entirely represented by the tiny sliver of air between the hub and the wheel. This ‘missing mass’ is not only quite small, it is quite near to the axis of rotation, so it can’t cause much imbalance. I think that the average operator is more likely to do more harm than good trying to balance a high quality wheel with OD 8 inches or less. The wheel manufacturers say as much.
Donald R. Cossitt I’d like to see Randy do several things differently for this video. First, I’d like to see how the arbor shaft and hub are balanced, prior to mounting a wheel. Maybe Randy checked that, but I didn’t see. Second, I’d like to see him show 2 balancing attempts prior to any truing, namely, in one case, deliberately mount the wheel offset to one side, and mark the side where the arbor hole of the wheel is in contact with the arbor (aka adapter or hub). In theory, that side should end up the ‘high’ side when the wheel assembly settles, since the mass of the wheel is slightly offset to the other side. Then, repeat the experiment with some shims positioned so that the wheel is centered on the hub. I think you can probably see where I am going with this. Geometry and symmetry tell us what I assert in my earlier comment, that a trued wheel, even if not exactly centered on the spindle axis, should have a balancing error related only to the ‘missing’ mass of the wheel near the hub. For a mis-centering as small as 0.001” (as estimated by Randy), this is a very small amount of mass very near to the center. Consequently, any imbalance should be correctable with a very small mass near to that clearance. If not, then the manufacturers’ claims of pre-balancing are evidently not true. One other thing: perhaps Randy can explain the nick on the black wheel that is clearly visible around 16:30.
Ok I will go thru the process you suggest Paul. The small nick in the black wheel was the way I received the wheel right from Norton.
Randy Richard In The Shop Bravo! I think we can all learn something from the process, and I look forward to it. I hope someone from Norton is watching, too.
+Paul Mathews - The heavy spot is very close to the nick in the wheel.
It's not the "missing mass" in the hole causing the imbalance, it's the "relocation" of the outer edge "mass" away from the arbor centre.
Called chasing your tail.
At times.
If you true up a wheel/hub that's not balanced, then any imbalance will sabotage the truing. It seems like you're setting yourself up for maximizing diameter loss on the wheel.
Better to balance first, perhaps tune the hub's position in the wheel if there's any backlash that allows it. Then true the wheel, then confirm balance. If you take a lot off truing the wheel, you know you're going to need to balance it again anyway. But at least on the first truing, an imbalance won't be robbing you of wheel diameter.
I guess looking at it another way, you've got two operations,
Truing eats up wheel diameter and is affected by balance.
Balance weakens the central portion of the wheel slightly but isn't dependent on truing.
Your process is correct, just needs to start with a balance before the first truing.
Thank you Greg. If you take care when mounting the hub to get it center, the amount of material you remove the first time is minimal.
you do not have the slightest idea what you are talking about.
Your balancing device suffers from too much friction. Your machine compounds the friction by having FOUR (large) points of contact trying to "drive" FOUR wheels driving EIGHT bearings. This friction will prevent a fine resolution measurement of balance. A better design is to place the arbor across two level, parallel round bars, as seen in other balancing videos. This design minimises the TWO VERY SMALL contact points.
yep the wheels i ballance are 24 inches od by 3 inch wide and can be a bitch to get just right lol