i need to know where to purchase a wavy washer more than .81mm thick and an o.d. of 215 mm. everywhere i look they are either too thin or too small. are they called anything else? maybe i could look under a different name.
Dear mustapha:
"wave spring"
I have built several designs around these folks products: URL:
Take a look here:
Don Kansas City
smally is the closest i could find--matter of fact, what i use now--but they are sooo thin. every company i've looked at has thin washers like that. is there a reason i can't find one?
now--but
Could you just nest two of them together?
I presume they don't come in thicker materials because the spring rate would tend to be too high for their typical applications. Of course, I'm probably wrong!
fwiw-
when a wave washer is "too thin" because the spring constant is too small, one usually goes to a bellville spring.
when a wave washer is "too thin" because the parts are too far apart, one makes the parts closer together, one uses uses two or more wave washers, or one uses one wave washer with a heavy (aka thick/hardened) flat washer
Oh, one does, does one? The difference in spring constant from a wave washer to a belleville washer is tremendous...on the order of a hundred to several hundred times more. The hole is also much, much smaller, so they are inapropriate for use where wave washers are normally used (like bearing pre-load, etc.). They are drastically different components for drastically different types of applications.
What one *does* do, often in such cases, is to nest wave washers, which are generally quite thin, as was suggested by Dean.
Don Kansas City
Dear Dean:
I concur. This is what they recommend for additional strength. The OP may have a particular requirement, that may rule this out, however...
No way! ;>)
David A. Smith
I've heard these called "crinkle washers", but I've never seen them that large.
Chris
Gee, several hundred times more? And there I was, looking at the PSI catalog listing wave washer (PSB0492-007) and belleville washer (PSBW0500-18), and both of them with the 1/2 inch OD and 1/4 inch ID (that would be the same diameters, fyi) but with wave washer at 4-5 lbs compression and belleville at 40-50 pounds compression. And I had thought if that wave washer spring constant was too small, I could go to a belleville. Apparently not if you are right.
Hundreds of times eh? Holes way different, eh? Wow, and the catalog says they are the same size. Imagine that.
OK - the psi catalogs I have must be wrong, then, if you are correct, - that is, since their catalog has the two the same id and od and they make the two kinds. You know, one cone-like and one wavy.
so
Wow. That's really interesting, since their applications are listed in the catalog - and in the dictionary - as being preload devices. Webster and the manufacturer must be wrong if you are right.
On the other hand, maybe one missed the part where one can spec a belleville matl thickness so it will have less of a spring constant than a wave washer of exactly the same OD and ID. For travel. Like in designing springs instead of getting them out of the box at the hardware store?
What's that got to do with a 215 mm washer? That's almost 8-1/2 inches OD. I don't find any off-the-shelf ones that size in my catalogs, but let's look at ones that are only about 5-1/2" dia. A typical wave washer that size has a compressed load of about 100-200 lbs. A belleville that size has a load of 34,000 lbs. A 215 mm one would have even more.
You argue like a little kid. The inside diameters of the 5-1/2" washers are
4.2 for the wave washer and 2.5 for the belleville and that's understandable. The wave washer, which is generally used for bearing preload, would have a slim margin that fits the outer race of a bearing without interfering with the balls.The belleville washer has way too small a hole for bearing preload. And it's design is totally inappropriate anyway. Since it doesn't have waves, the OD presses all on one side and the ID all on the other. The OD would have to be oriented toward the housing shoulder; if it rested on the outer race, the ID would just stick through the hole and do nothing. This would make the ID rest up against the workings of the bearing, or on the inner race...and that's if you can find a bearing with a shaft bore small enough to even fit through the washer! The whole point is to provide pressure between the housing and the outer race. This is not what bellevilles are for.
And why would you want to preload a bearing with 34,000 lbs anyway?
Oh, this is priceless! Now you're going to custom make washers just to prove a specious point? The OP wants to buy a thicker wave washer.
You told the group with great hubris that, "When a wave washer is 'too thin' because the spring constant is too small, one usually goes to a bellville spring". I have nineteen years' experience using both kinds of washers, as do many others who read this group. You apparently have very little, or inadequate, experience.
How old are you, kid? Don't fib now!
Don Kansas City
////x
Hate to break in on a good dog-fight but that's what heppens if you take too uncritically the questions from a fellow who is not necessarily giving you the facts.
Any one want to bet that Mustapha's 215 mm is in fact 21.5 mm???
That would be about right for the thickness he has in mind. And he HAS been sourcing them already.
Better wait for him to explain what size he REALLY wants and for exactly WHAT application....
Sorry guys, back to your corners :-)
Brian Whatcott Altus, OK
why? if it's a custom as you say, I can have nearly any preload I want.
Can we agree that your "hundreds and hundreds of times" claim is bogus, that the "little bitty holes Bellevilles must have" claim is bogus, and the claim that one cannot choose strength for either out side of "hundreds of times" is also bogus?
You undoubtedly have the experience there, too.
Notice that when your argument is lost in the light of point-by-point refutation by fact, and your avenues of shifting reference are blocked, you attack the carrier. A sign of argument lost, according to Aristotle.
Listen, carefully, now, Donny - The wave washer is a shape, and the belleville is a shape. And you can make them thick and they will be big and strong, or you can make them thin and they will be small and weak. You get to pick !! neat, huh? And even better, you can pick the stuff they are made of in order to make them even weaker or stronger than thickness alone does!! So when you get to be an engineer, you can have big, strong, really thick wave washers and itty bitty really thin bellevilles, and the thickness and material can make the same OD-ID belleville is weaker than the wave washer !! Shape.
Ah - clarification. You guys only use really light needle and ball bearings rated for light loads - like a 4 inch shaft with a 5.5 inch ball or needle bearing. And apparently you don't preload bearings, you use the washers to hold the bearing in.
Yes, our bearings have inner and outer races too, and they aren't the same diameter (except on thrust bearings). And so to remove cold-run tolerancing by loading so as to improve accuracy, stop slap, reduce flutter, etc., we only load one race - called preloading the bearing. You guys load both races?
I suppose its the habit of machining our bearing seats for the race response we want, and for picking ID holes in the washers larger than the shaft. Like using under a 2.5 inch shaft on a 5.5 inch od spherical roller bearing.
Since it doesn't have waves,
Exactly. preloading whichever race one choses as the relatively fixed race, pushing it against the pressed race.
The OD would
That is not preloading a bearing, BTW. That is holding a bearing. And try holding a spherical roller with a light washer.
This is not what bellevilles are
you attacked a statement about the basics of flat-spring-type washers that said if you need more load, try a belleville,
me? not all that old - PE, BME, EE - 32 yrs machine design: built custom test machines for shock and vibration and fatigue, hoists, cranes, rails and like from components to systems, controls to structure; chief engineer, VP engineering; President and chief engineer of consulting firm since 1984 - about 21 yrs. Yeah, I've seen a few washers. In the robots, the hoists and cranes, the odd designs that corporate engineering departments couldn't get to work without help.
Your 19 yrs experience made you new out of school (you did say you went to school, right?) back when I was a chief engineer already with thirteen yrs machine design under my belt, had been a CEO once by then, and was just taking over as a CEO and principal engineer of a new firm once again.
Exdperience is not time in the saddle - it's miles ridden and problems faced.
nuff on this...
---------
"Don A. Gilmore" wrote in news:5%Hje.82$ snipped-for-privacy@tornado.rdc-kc.rr.com:
lbs compression and belleville at 40-50 pounds compression.
Hrm....
All right, all right. Let's call a truce. I re-read my post and see that my rhetoric was getting way too abusive. I apologize. Must have got up on the wrong side of the bed.
You've got me on experience, if not education. My résumé isn't that lackluster, though. I have been interviewed in newspapers, magazines and on radio shows all over the world, including the New York Times and NPR.
I see also that Anthony came up with a source showing bellevilles used for bearings. They still appear to have higher spring factors, but their deflection at load is very small, resulting in a light force and they're using them back-to-back so that the OD provides pressure on both sides. I've got to eat crow on that one since I have never seen that application. Again, please accept my apologies for being a jerk.
What is your name, by the way? It feels strange apologizing to a punctuation mark.
Don Kansas City
Hey guys, what happened to the OP?
Did he really want a 215mm OD wave washef?
Hey guys, what happened to the OP?
Did he really want a 215mm OD wave washef?
truce it is - I do get a little testy sometimes
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