Other day we found a fan manufacturer that uses the coin test using the "standardized" 10 SEK coin as a EOL testing before shipping. Is that a standard procedure that you have seen and is that a reason why we have a healthy amount of consultant work on fans new and old? Real question is now, what will that coin test compare to relevant ISO standards? Any unpublished studies out there on the subject? As the cointest is not a unknown feature along with the waterglass test for more subtle machinery it maybe would be interesting to check it out. I can directly see the limitations of not reading in 3 directions and other "it depends on" issues as coin position, size etc. It may be a great export opportunity for 10 SEK coins if a standard can be defined ;-). Olov

Are you talking vibration when you refer to coin test?
If so, in the UK we used to have a small, twelve sided brass coin worth three old pennies, a "threepenny piece".
For decades this was used by engineers to establish acceptable vibration levels on a piece of equipment. He would stand the coin, on one of the small "flats" on its side, on the machine in question. If it stayed upright, the machine was OK. If it fell over, corrections needed to be made.
I don't somehow think this would pass todays more stringent standards!

Oli,
Years ago when I first learned to balance with the IFD 350 and a strobe light, I had a couple of times that someone would put a nickel on its side to test the vibration. I don't know if this was ever an acceptable standard but it is a similar test now talked about in three countries. Makes one wonder just how wide spread it was doesn't it?

Ronnie

I am in Indiana and the nickel test was popular here too. We had a joke that if the coin fell over put a little glue on it to help it stand up.

I think it´s as spread as coins are, and yes I always vibrate and that´s what I test :-). I vote for having the Swedish 10 Crown coin as the standardized item for this purpose, just because it´s so easy to have around! In the old days we had copper plate "coins" that was like 5-10Kg, that would be fine for reciprocating machinery? I must admit that the obsolete edgy coin also have some advantage. Having a coin that is circular must then be a more stringent test than a edgy one? It so happened in this case that the test by definition was performed at the node where the flange mounted motor was attached, in the other end it had 45mm/s. So the rejection rate was not so big as it maybe should have been. One of the other problems with factory testing is the mount, in this case loose on a wood pallet loose on the floor. In other cases like a diesel firepump loose on a workshop wood floor. Customer calls, what levels would be expected with that mount? Answer, a lot more than bolted to the concrete after delivery. Olov

I thought I was the only one still using this technology. I have a nickle standing on all my equipment. I don't even take the 2120 out of my office unless a nickle has fallen over. Sure saves on data collection time.

Just kidding! Ha, Ha, HA,

Some of you are thinking, "who would ever use a coin to determine vibration condition?" I used to balance some hammer mills, and the "nickle" test was actually in the user's manual. In the U.S., a nickle is the only coin that is going to stand on edge I think. You might get a penny to work, if you were really, really good.

Some customers are so "backwards" about vibration and what is good or bad, that it takes something like the coin test to illustrate what "good" really looks like.

Today I balanced a large overhung fan at a lime plant. They said it was vibrating "just a little too much." Of course, the as found reading was 20 mils at 750 rpm!! It really did seem to be just a balance problem, but we eventually put over 5 lbs of weight on it, at a 42" radius. It has some pretty massive weights on it from a previous balance (supposedly 3 years ago). It was either balanced dirty, or the shaft has some bend in it. I measured 0.007" TIR about 4" outboard of the fan-end bearing, next to the housing seal. Would that do it?

Anyways, it was a beast to balance (pretty well exhausted my supply of clamp-on weights) and the wheel was stainless... all they had to make balance weights out of was a piece of 3x1/4 angle. After careful measurements, much weighing of rods, accounting for radius reduction (clamp-ons vs. plates), and welding 8 seperate pieces of plate (4 stacks of 2 pcs.), it rolled up at 1.1 and 1.3 mils, horizontal.

And, yes, the nickle did stand on edge!

As a consultant, I guess you can charge the customer with an adder.

For those working for companies, does the companies supply your work tools, including coinage?

Bill, you're probably not going to believe this, but the customer was not much impressed with my instrumentation. He did like that I had a portaband to cut weights, 18v cordless grinder to prep for the welds, and 18v impact for closing the hatch, etc. And he really liked the "standing nickle" when I was done. As for the report, he said "I don't need a report... just send me the bill." And he is an engineer and the owner of the plant.

Ultimately, we are responsible for solving the problem at hand, but the customer decides what looks "good" to him, and what he's impressed with.

Your toolbelt is truely bigger than I imagined.

I've found jobs go a lot better when I have all the stuff we need, which the customer usually does not have. The old tool belt really gets heavy when I do an alignment and have to add a 6-foot 'pinch bar', full assortment of slugging wrenchs, portapower with several jacks, 3/4" socket set....

And you could ask if the standard known identification of a vibrationconsultant are arms that reach to the knees like a baboon, any other similarities unintentional including myself ;-). Olov

It seems that "All the nickel test tells us is that nothing is bent or way out of balance" as per this article:http://www.newwoodworker.com/nickeltest.html

Offering monetary offerings to the machinery gods never hurts. Keep a coin change machine on your toolbelt.

Free coin balancing test:

http://www.chemacinc.com/page.cfm?content=news_item&id=61

This message has been edited. Last edited by: Josh,

Sorry Oli, but it will have to be a 1 Euro coin. Although I think I do have a 10 crown coin, most of the rest of the world has never seen one.

How did they get two nickels to stand on top of each other in Josh's most recently posted link? Superglue?