Vibration isolating rollerballs

[Daudio]

I misquoted the price for the 6061 material: he told be $85/set (not $75).

 

We should have the numbers to get the 20 set minimum price of $130/set (6 blocks).

 

Jon,

 

Is this the Group Buy thread ? It doesn't say so in the thread title ?

 

Sorry, but I'm confused about your prices for a set (3 or 6?), and the minimum. Is that for each buyer, or for all combined ?

 

I suggest that the project only do the bearing blocks and forget about the bearing balls. I think it would be better to let each individual chose what type of balls they want (SS, TC, ceramic), with links to the best sources.

[Daudio]

Mike will do the 1" bowl (0.96) with a depth of 1.8mm (as per Post#30) with an overall diameter of 1.5" and a depth of 1/2". He states that he is using high quality 7075 US supply which will alone cost $40/set. .

 

jabbr,

 

What is the diameter of the curvature of the bowl ?

 

I take it that the the cheaper 6061 alloy is no longer an option ?

[Daudio]

So diameter 2".

 

Thanks. That is the same curvature as Barry's "Iteration 1". Nice, but I had hoped that we could have had a shallower bowl, perhaps a 4" dia. curvature. I consider the Ball/Bowl curvature ratio a very important factor in these type devices, and the higher the better.

A ratio of '1' would be a bowl that is the exact same diameter as the ball, and thus a tight fit, without any possible motion, or isolation effect. A flat surface would have a ratio of 'infinity', and no self centering action, and I suspect other drawbacks. We want something in between, but exactly what ratio is optimal, I don't know.

 

 

Much of the work involved is in setting up the machining. I suspect that there would need to be some minimum number of sets for a run of 6061 but he may keep 6061 in stock. I'm interested in 7075. If people are also interested in 6061 we could use this thread to get a rough number and then ask Ingress.

 

I can't quite get myself interested in a $130 experiment for only one piece of gear, when it's the same old curvature, my funds are limited, (I just got my property tax bill ), and I have my entire system already outfitted with my acrylic devices.

 

So, sorry, not joining in on this buy. Maybe later ?

[Daudio]

the bowl shape is not necessary for the isolation to happen, however without it the system is like a pencil sitting on its point.

 

John,

 

If the bowl is unnecessary, and there is no slope for the ball to push against, where is the isolation occuring ?

 

Somewhere in the 4 tiny contact points ?

 

 

Fine Forth,

Dave

[Daudio]

Don't you think maturity and civility also implies acknowledging where you went wrong in modeling the phenomenon, as well as recognizing that when people disagree with you and point the facts to you, they aren't being 'unfriendly' in any way? Maybe practising what you preach about civility and maturity is in order.

 

YashN,

 

I see someone rapidly heading towards being placed on the Ignore Lists of probably more then a few other CA members. And I don't understand why ???

 

You have done a lot of reading in many disparate and far flung areas of vibration isolation and conrol. Which is great, but my very strong feeling is that you have not yet fully integrated all that data in your head. That, and the primitive state of your home experimentation, make me regard your statements with less impact then from someone who has been involved a lot longer, and done much more direct experimentation.

 

I find your arrogance towards disagreements misplaced and counterproductive, and a poor approach towards unraveling the mysteries of this interesting area which confront us all.

 

Please chill out, and return to the search

[Daudio]

IIt occurs to me you could make use of a flat surface and weighted ball bearings. They would need to be larger. If the bearing is weighted heavily to one side that side will end up being down. Align all 3 or 4 such bearings and small disturbances will still re-center themselves. Of course this would be a higher frequency of resonance due to the effectively shorter pendulum.

Another possibility is a hard hollow bearing with fluid in it. Fluid less than full would have some of the same effect if high viscosity. It would dampen as well as re-center for small movements. That might be tricky to optimize.

 

Interesting idea of using a ball with unequal mass distribution and flat surfaces. Could well work as you surmise !

 

But where will these balls come from ? I've never heard of any such thing, which is not saying a lot, but...

 

My bigger concern is that, if it were possible to obtain such strange little lop-massed creatures, I doubt that they would come in the high precision concentricites (G25, G10, G3) readily available now. And, I suspect, that that precision, and related smoothness, is a large factor in the performance of these isolation devices. Not hardness, or mass (IMNSHO).

[Daudio]

Would a flat surface with a lip to prevent ball(s) rolling off allow more of the motions of cone drivers to result in unproductive reactive motions of the speaker and balls, in contrast to a curved bowl restricting those unproductive reactive motions to a greater degree?

 

I would suspect that the ball would spend all of it's time resting against the lip, wherever slight mis-leveling leads it. Thus we still have a curvature, just not a stable one.*

 

I don't recall hearing about any evidence of anything more then invisible micro-motions in the roller systems (other then the usual conjecture). That is, once the device is setup and stabilizes.

 

 

* I just had to 'level' my Mini/DAC support, as it continually wanted to slide off to the left-front, and had to be restrained by a chunk of foam. By adding a 3"x3"x1" steel block I managed to level the components over the air bladder, and then the residual friction of the rollers (bottom bowl, flat top), and cabling allowed me to get the top support plate centered.

[Daudio]

I think you bailed out quite early of the original thread because you had 'difficulty following me' or maybe the rest of the thread, including the more sound theoretical and modeling aspects...

By your own admission, you have difficulty 'following me', but that doesn't mean what I write or do is without value, just that it's difficult for you to understand...

 

I had/have difficulty following you because you switched from one subject to the next so fast and furiously, there wasn't any point in trying to 'follow you'. I didn't see how there could be much depth, with that little attention to any one thing ?

 

Plus, I'm sure I've made it quite clear that I'm focused on only the roller block type devices, and in more of a actually implementable improvement respect.

 

 

you probably would also have seen a post by John Swenson saying there could be merit in a mostly flat surface...

This is the reason why you hadn't yet understood that the ball being centered or the ball being brought back to the center by gravity isn't necessary for proper isolation...

 

Well then, you haven't been paying attention. Yes, I did initially think that the curvature interaction was part of the isolation process. But I learned and evolved, and that is evident in my later questions and writings.

 

The fact that you use that to slur me (as you have others) doesn't do your reputation any good at all. Are you consciously trying to piss people off ? I have no idea why ?

 

 

The only thing primitive here are your understanding and accusations. I probably already made a lot more experiments and measures than you did.

 

Sorry, but a few furtive posts about marbles and bamboo, doesn't constitute advanced experimentation in my book (fully isolated system). I'd be happy to help you move that along (like my post with the bearing sources link), but not if you trash and disrespect me and other CA members I respect.

 

You are only shooting yourself in the foot with these angry, defensive posts

 

One last time; please chill out, and work with the forum members !

[Daudio]

I'm working with Mike at Ingress. He is making a set for me, smoothed with Emory 320 and I will check it out. I'm not sure if a mirror polish is needed -- this may work well.

 

I found a picture of a Ingress bowl block and cropped it some, to show the bowl finish:

 

 

As you can see the stock Ingress bowl has (relatively) rough machining marks. But then, these are the least expensive of the 4 commercial roller type isolation devices available now.

 

I too believe that the smoothness and concentricity of the bowls and balls are a big contributor to the quality of these type of devices.

[Daudio]

... the Ingress ... are the least expensive of the 4 commercial roller type isolation devices available now.

 

The FIM Model 305's have a polished bowl, but they are 3 times the cost of the Ingress. The Symposium RollerBlocks also have a 6 micron polished bowl, but at about 7 times the cost ! The Symposium Jr's have an anodized bowl, and the similar HDSE's are hard anodized, and while they both appear to have a nice bowl finish (from small pix, no specs), they are not polished, and at 3 - 4 times the Ingress price.

 

As jabbr is discovering, good, smooth, finishes cost money

[Daudio]

Yes. My understanding is that when very high grade equipment is made there is one shop that does the machining and smooths to Emory 320-400 before being sent to an anodization and finishing shop that anodized and then places a mirror polish. Question is how much that second step costs-- reasonably

 

jabbr,

 

I don't understand

 

I thought that an anodized finish on aluminium, is a very, very thin coating, almost a molecular layer. I don't think that could be polished, only the underlying surface before treatment.

 

Am I missing something ?

[Daudio]

The bowls cups need to be in qty to be cost effective (obviously) and I had some crazy $ quotes and lead times from various shops, but through my connections was able to get them well under $20/ea (7075, polished). As far as making them, it took a 1 hour machine set up time, but the cut time is very quick.

 

Foggie,

 

Your bowls blocks look very nice !

 

What is the diameter of the curvature ?

[Daudio]

Those are my Hip Joints design. The bowl shape is described in post #30

 

Barry,

 

I thought so, but wanted to be sure.