Surface Grinder Adapter Balancing Rings

[thestelster]

Ya sorry, I was just doing that part in my head. My bad.

0.050 is more than enough even if it did require significant strength.

Another point is that the screw thread doesn't need to be more than 20%. Power tapping suddenly looks far less scary!

Since I don't have a tapping head, I'd have to do it the old fashioned way and just let the threads pull the spindle with very light presssure, but it would solve the dilemma you mentioned about dying before I finish the job. (btw, that was mean!) LOL!

I don't have a tapping head either. I just put the tap in the drill chuck. (And I have a keyless chuck, which people have said that it will loosen the grip on the tap when backing out, but I've never had an issue up to 3/8"-16)

Make sure you're using a spiral "gun" tap.

(There was no disrespect intended, but hand tapping 96 holes at 4 minutes per hole is 6.4 hours! I was tapping at 300rpm. I don't know if that's an appropriate speed or not. But worked fine. WD40 as a lube. Plus I do have a brake resistor for my mill, and it stops pretty quickly.)

 

[RobinHood]

For reference, this is how Sopko themselves does it.

View attachment 39142

Both disk attach with a set screw at the heavy end and you balance by offsetting the two Disks as required. The cavities face each other so grinding dust doesn't accumulate.

From what I read, the kinetic precision system method is WAAAY easier to use.

These are the type of balancing weights I have made for my SFC grinder wheel hubs. They work well.

 

[Mcgyver]

Nice job on the weights. A bit of a similar approach to how a watch balanced wheel is balanced (called poising)

I'd bet the guys on the floor know what they are doing, but the write up (unless I missed part of it) I think gives incorrect information. They mount and balance the wheel then dress. No....mount, dress the wheel, don't disturb it on hub, pull the hub and off the machine and then balance. The way they describe it, you're balancing the wheel with its OD eccentric (always is, even if made perfectly, clearance with the mounting hole will cause it). When you then dress it, you make the OD perfectly concentric and put it out of balance.

Here's another idea that might work for the bench grinder, balance with loose steel balls in a track. I always liked this video, I don't think that my brain would ever have accepted the theory without seeing it presented as such.

A version I made. Semi successful, but its not the idea that failed....I just didn't have enough weight and distance for the amount of imbalance. More work needed......the idea is, fixed to a shaft, they about eliminate vibration.

 

[thestelster]

They mount and balance the wheel then dress.

They actually tell you to do their sequence twice, as well as going up the sides of the wheel.

 

[Susquatch]

I don't have a tapping head either. I just put the tap in the drill chuck. (And I have a keyless chuck, which people have said that it will loosen the grip on the tap when backing out, but I've never had an issue up to 3/8"-16)

I've never tried it so it will be new territory for me if I do.

I've heard that about keyless chucks too, but I've always thought it was just a wives tale. Why would it do that?

Make sure you're using a spiral "gun" tap.

Is that really needed with say a 20% thread?

(There was no disrespect intended,

Ya right....... LOL!

but hand tapping 96 holes at 4 minutes per hole is 6.4 hours!

Ya, that's a long time..... Then again I prolly do have a few years anyway! LOL!

I was tapping at 300rpm. I don't know if that's an appropriate speed or not. But worked fine. WD40 as a lube.

Sounds good to me.

Plus I do have a brake resistor for my mill, and it stops pretty quickly.)

That I don't have yet. I'm still working on the control box!

 

[Mcgyver]

They actually tell you to do their sequence twice, as well as going up the sides of the wheel.

I must have missed that ...... that'll get it done. Still see no point in the initial balance before dressing, unless its just a safety thing....e.g. make sure there isn't a screw in one hole etc

 

[Mcgyver]

I've heard that about keyless chucks too, but I've always thought it was just a wives tale. Why would it do that?

It's been my experience that they loosen on reverse. I use a jacobs, not my best one, and tighten on all three holes (makes a difference). I really should make an adapter, simple enough, bar held in the chuck with a bore with some set screws to lock on the square section.

 

[thestelster]

I really should make an adapter, simple enough, bar held in the chuck with a bore with some set screws to lock on the square section.

Or collets...in fact you can get ER tapping collets that have a square recess at the rear section.

 

[Susquatch]

Or collets...in fact you can get ER tapping collets that have a square recess at the rear section.

Another new discovery. I never saw that before.

 

[Bandit]

The hub style "a smile" made and showed is what we were using on crank grinders, the balancing seemed easy to me, as per #114 in "is a taper attachment worth it". Each grinding stone in use had its own hub. The biggest grinder I used, had 4 different width stones for it. We always rechecked balance after trueing a new stone.
A new stone was cause for butterflies, not the good ones. After mounting hub and balancing, mount to machine, and check for run out on face and sides, if seemed not to bad, run machine up to speed and hold for a few minutes, shut down and let stop. If it passed those checks it was dressed, face, then sides. Balance rechecked, generally would be good. It was always a bit before you "trusted" a new stone, as you were pretty much in front of it when grinding.

 

[Susquatch]

Make sure you're using a spiral "gun" tap.

OK, maybe this one is new to me too. What does a "spiral gun tap" look like? I always thought gun taps has straight flutes but an angular tooth cutting profile. Very hard to make. Not the same as a tap with spiral flutes.

 

[thestelster]

OK, maybe this one is new to me too. What does a "spiral gun tap" look like? I always thought gun taps has straight flutes but an angular tooth cutting profile. Very hard to make. Not the same as a tap with spiral flutes.

Sorry....Spiral point tap. They call it a gun tap because it "shoots" the swarf forward.

"What is a spiral pointed taps ？ Spiral pointed taps have straight flutes for coolant distribution. They have a slanted angular gash in each flute on the front end of the taps flute at the cutting chamfer to manage the chips. The tap is used mainly for tapping threads in through holes."

 

[Susquatch]

Sorry....Spiral point tap. They call it a gun tap because it "shoots" the swarf forward.

Thanks Stel.

I spent some time in the shop today playing around with all this. Your wheel arbours are just like mine.

I don't have any blocks tall enough to put rods on to clear a wheel, but I can prolly stack some 123 blocks to be high enough. I didn't see any levelling shims in your photos from a while back. Did I miss that or wasn't it important enough to worry about?

 

[PeterT]

Here's another idea that might work for the bench grinder, balance with loose steel balls in a track. I always liked this video, I don't think that my brain would ever have accepted the theory without seeing it presented as such.

Many years ago, early 80's? I met an engineer through hobby stuff who worked for a company implementing this technology. They had a conference room demo which I saw, no doubt to get the basic principle across without heavy engineering or math. It was a 8" household fan with steel paddle blades. Remove 1 of 4 blades & it would buzz across the table hopelessly unbalanced. Attach the magic balancer collar (still only 3 of 4 fan blades) & there it sat with a satisfying, silent hum as though it were bolted to concrete. He mentioned the idea/patents were around forever. I think their niche was design software to design units for various applications. It wasn't just a single track of bearings it could be many, different ball count & diameters & densities. And if I recall, dampening fluids. Some were for specific high RPM applications like disc drives or centrifuges where vibration was a big deal. Others were adaptive like if a machine element became unbalanced by wear or whatever. I think they had some buy-in, but I lost track of the story.

 

[thestelster]

Thanks Stel.

I spent some time in the shop today playing around with all this. Your wheel arbours are just like mine.

I don't have any blocks tall enough to put rods on to clear a wheel, but I can prolly stack some 123 blocks to be high enough. I didn't see any levelling shims in your photos from a while back. Did I miss that or wasn't it important enough to worry about?

I did have to shim both 2-4-6 blocks on the one end. It is extremely important to get it level, at least in the axis direction that the arbour/wheel rolls.

 

[Former Member]

There are some good old videos on YouTube about balancing rotating objects. Most balancing techniques are based on static methods ie add subtracts wts until rotation does not occur or bubble level centers. This works for low speed applications but at isn't a true balance.

Better systems use dynamic balancing which spin the item and add/subtract wts to ensure that while balanced do not inflict a torque on the shaft due to location of the counter balance (sorry if I'm not explaining it well, I don't remember the terminology used but do remember the concepts). Think expensive tire balance machines as they add wts on inside or outside rim to achieve balance.

 

[Susquatch]

Made my first balancing arbour today.



Fits perfect. Just need to polish it a bit, then part it off, and try it.....

Decided not to put threads on it. Doubt they are necessary for balancing. And this is much cleaner.

 

[Susquatch]

As crude as it is, it works! But I seem to have a severe balance problem with the very first wheel I tried - a course 1/2x7 wheel. It took a big 1/4 x 2 inch machine screw and a 3/8 nylock nut to tame it. That's like 5000 set screws!



I tried re-indexing the arbour in the off chance I screwed it up in some unknown way. That didn't affect the wheel one iota.

Good confirmation that the arbour is ok. But also confirmation that the wheel is WAAAAY off.

Yes, it has been dressed. In fact, I have even used it to dress my mag vise with very satisfactory results.

After a bunch of txt msg exchanges with @thestelster, till we both dry of ideas, I decided to try a different wheel. Why not a bigger 8x3/4 one since I already had one on an arbour. To nobody's surprise, it seemed to like the equivalent of just two or three set screws.

Anybody else have bad wheel experiences like that?

Any other thoughts about things I might be doing wrong?

 

[Ian Moss]

just put some epoxy both sides of the wheel and about 1/2" from the circumference. The added distance from the axis will require much less absolute weight and it will take a lot of redressing due to use before you get anywhere near the epoxy.

 

[Susquatch]

just put some epoxy both sides of the wheel and about 1/2" from the circumference. The added distance from the axis will require much less absolute weight and it will take a lot of redressing due to use before you get anywhere near the epoxy.

I think I might do that for this bad wheel. And who knows, I might end up doing it for most wheels.

I am gunna make at least one balancing ring though. It will be a good comparison.