Spent parts of 2 days this week trying to field balance a small, vertical-spindle centrifuge at a local plant. Machine was very ill behaved but we finally got it down to what seemed a reasonable value, 0.13 in/sec pk at 7500 rpm, but still not quite as smooth as the identical machine next to it which was running 0.08 ips.

Someone suggested we try the "nickel" trick. After we got the wind blocked off enough, the nickel not only stood on edge, but slowly twirled in a circle. If we consider the standing nickel as grade 'A', is the "twirling nickel" an A+ or an A-.

Incidentally, I once balanced a large hammer mill, and the OEM manual actually stated that it should be balanced until a nickel stood on edge, with no other standards or even numbers mentioned.

I haven't tried calculating the actual balance quality yet, but am not sure I'll be able to since the "balance solutions" we were getting were so out-of-whack.

Cool! teach me that!!
Good In = Good Out!

On bad machines set the nickle flat. If it bounces off the vibration is not acceptable, or one could use a quater.

If the coin continues to bounce off cheat and use some glue.

When I was a technician, we'd lay a nickel flat on the machine. If it rattled, you knew the vibration levels were 1 g or greater.

When I got my degree and became an engineer, we'd use the same trick....except with a quarter!

Never heard about a nickel on edge before. I guess I need to practice to get it to stand up on a non-vibrating surface before I try it

Jon
Spintelligent Labs

Coinage is not considered permanent monitoring unless you use the glue. Coins have a tendancy to walk off.

Come to think of it, a spinning coin would be gyroscopically stabilized, like the satelites or a football that has been passed.

We used to do that coin trick but with 1 SEK coin and on our toy grinders used for balancing training until it wandered off, hit the rotating balancing wheel and made a dent in the roof. That place is now a restaurant so the dent is gone. We now place the coin at the center of the machine. Olov

Our plant recently had a new ball mill installed. The lead guy from the installation crew was beaming at start-up because a nickel would stand on edge on the gearbox driving the mill.

My boss would prolly rather give me a nickle than buy a 2130

A property of nickel is; heat it and it becomes magnetic if I recall correctly. Would that mean the worse the machine the better it sticks! The nickel balance trick has been around for a long time but generally doesn't command much incentive from the formal report to pay a bill in triple digits - it was only off 2 cents!

Is the penny standard even better?

I would think so; recent released info places the penny's worth at ~1.25 cents. Of course one has to bear in mind the date as 1988 could weigh more than 1971 plus the alignment of the stars and angle of the sun may have a play. But rehersing back through the slossy grey matter wouldn't a 'gold standard' be better? Never really heard of a nickel or penny standard but if Bush keeps in much longer the buffalo will be extinct and the penny in jeopardy or I could be wrong. Technology; onward and upward - where's Susan B. Anthony? Little doubt where JFK is. Did anyone read this far down? Another fabulous day!

I was just referring to the penny being thinner. Maybe if you file a flat spot on a dime, that would work, too.

A cheaper meter that has the same type of precission is the "V" meter. Take a piece of cardboard or paper and draw a "V" on it. Attach it to the machine and where the lines vibrate together visually you can tell the amplitude.

I have seen these made by some company before, but I don't remember where.

Be careful that the meters don't catch fire.

Bill,
I saw one of your vees once on the shaker portion of a Prab scrap metal conveyor. I didn't ask them if they wanted me to balance it, though

I was asked to balance a "hog" at a sawmill to the nickel standard a while back. I asked what was their indication that it needed balancing. They said it was shaking the platform over 200 feet away.

I used nickel glue.

Rusty,

If the Nickel was moving (spinning), then you only get an A-. The best grade is reserved for motionless Nickel. That's just my 5C!

Walt

If it's real good do you get change back?

The first time I ran into the nickel standard was when an old building Chief Engineer in Chicago tested a motor my guys installed in 1994. We stood there with all of our laser alignment equipment, vibration equipment, winding test equipment, etc. ready to show our completed work per the contract. He walked in, placed a nickel on edge after we started the equipment, said it was good and walked out.

Never did get the knack of it, myself... my hands are too shaky... which is why I perform surgery on machinery and not people.

Howard

I have not used the nickel standard.
However years ago when a quarter was worth something I told a coworker at a grocery store that I would give him a nickel for every quarter he could stand on its edge. He went to the back room and hammered a flat on the quarter. When he stood it on edge, I threw down the nickel and picked up his quarter and put it in my pocket. He wanted to fight over it.

Some have no sense of humor. I had a crew in performing alignment during a shut-down at a paper plant in GA. At the beginning of the week I asked some of the guys if they were interested in a raffle as I had a new washer and dryer I wanted to raffle-off. So I sold tickets all week until lunch on Friday. The winner was presented a new rag tied to a new shiney 1" plated washer (flat washer) and do you know they wanted their money back!

I took off my ring and pushed a quarter through it and still no appreciation. But I did drop a quarter through a piece of 1/2" pipe and everybody did appreicate that. They only got their money back on the washer and dryer though.

Alright Sam,
You'll have to explain how you can fit a quarter through your ring or a half inch pipe.

Nick

Take a small piece of paper, tear it into 4ths, and a quarter of it will slip easily through a ring or a piece of 1/2" pipe... At least that's how I'd do it.