Vibration isolating rollerballs

[jabbr]

There has been a great deal of discussion vibration isolating rollerballs on the thread started by YashN and a specific design offered by Barry Diament in this post: http://www.computeraudiophile.com/f8-general-forum/equipment-isolation-and-vibration-damping-24805/index2.html#post436931

 

tne found this: http://www.computeraudiophile.com/f8-general-forum/roller-type-vibration-isolation-devices-info-24991/#post440832 and I contacted Mike: http://www.computeraudiophile.com/f8-general-forum/equipment-isolation-and-vibration-damping-24805/index13.html#post441283 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). He's ordered 7075 product and needs to retool for the job so we are looking at August at this point.

 

So we can keep track of how many sets (and confirm the 20 set minimum) we can list the orders. Email Mike at [email protected] to arrange shipping and payment.

 

Jon

 

Username # Sets 7075

jabbr 12

[groovybassist]

Email sent.

 

-Mike

 

Username: groovybassist

 

# sets of 7075: 2

[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.

[groovybassist]

I believe a set is 6 pieces (3 tops and 3 bottoms) and 3 bearings. In terms of price, I'm reading it as each set is $130 , assuming the group collectively buys a minimum of 20 sets.

[Solstice380]

I believe a set is 6 pieces (3 tops and 3 bottoms) and 3 bearings. In terms of price, I'm reading it as each set is $130 , assuming the group collectively buys a minimum of 20 sets.

 

I'll buy a set just to measure their mechanical resonance spectrum!

[Solstice380]

I'll buy a set just to measure their mechanical resonance spectrum!

 

Actually, maybe jabber would allow me to measure a set of his, he's signed up for 12 sets!

[jabbr]

Right 6 pieces per set and the price is for everyone here assuming we have a minimum of 20 sets -- we are there already assuming everyone whose told me they want a set commits-- you can throw away the chrome steel bearings if you like -- they are very cheap.

 

I've just arranged for this with Ingress. Everyone can email Mike and arrange shipping and pay.

[jabbr]

Actually, maybe jabber would allow me to measure a set of his, he's signed up for 12 sets!

 

Sure I guess -- I'm keeping 6 sets and a friend of mine is keeping 6 -- we are getting these and then testing out different bearings -- probably my network switches and NAS will keep the chrome bearings but tube amp will get Silicon Carbide (or Tungsten if his uncle can get us a good deal)

[jabbr]

I believe a set is 6 pieces (3 tops and 3 bottoms) and 3 bearings. In terms of price, I'm reading it as each set is $130 , assuming the group collectively buys a minimum of 20 sets.

 

Yes

[jabbr]

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.

 

I don't intend to take any payments myself or handle any shipping -- I just cajoled/convinced Mike @ Ingress to retool & get some 7075 for us at a good price. I have no relationship with Ingress other than good customer:)

[InfernoSTi]

I'm going to grab three sets so I can have these under a few more items. E-mail sent.

 

John

[AnotherSpin]

As I understand, the question of design/measurements of bowls for group buy is open. In one of his posts in other thread Barry gave an idea of some measurements (not all) he used. I am sharing the design (everything is in mm) which I used for the bowls I have already for some time. It were machined before I saw those mentioned Barry's measurements (which I would use myself if I knew it then). But, Barry hinted he have some new ideas, maybe he will tell us more now... Anyway, let's discuss.

 

[InfernoSTi]

For comparison to AnotherSpin's post above, here is what Barry posted in slide #30 of the other thread:

 

Iteration #1 uses a .96" diameter bowl that is a section of a 2" sphere. Bowl 1/8" deep at the center.

Balls are 1/2" chrome steel.

[Superdad]

Actually, maybe jabber would allow me to measure a set of his...

 

You want to measure Jon's balls?

[Speedskater]

You want to measure Jon's balls?

Why?

Are they deflated?

[YashN]

As I understand, the question of design/measurements of bowls for group buy is open. In one of his posts in other thread Barry gave an idea of some measurements (not all) he used. I am sharing the design (everything is in mm) which I used for the bowls I have already for some time. Anyway, let's discuss.

 

[ATTACH=CONFIG]19531[/ATTACH]

 

For better isolation, you'd need the shallowest curve possible. Large recipients would allow that.

 

Personally, I'd use a flat dish, with curves at the very end to prevent falling off of the bearing. Proposed that mid-thread or so, after John Swenson's gedankenexperiment. Experimented a bit manually with my girlfriend's pancake pan.

[jabbr]

You want to measure Jon's balls?

 

Use to have brass, switched to carborundum

[jabbr]

For better isolation, you'd need the shallowest curve possible. Large recipients would allow that.

 

Personally, I'd use a flat dish, with curves at the very end to prevent falling off of the bearing. Proposed that mid-thread or so, after John Swenson's gedankenexperiment. Experimented a bit manually with my girlfriend's pancake pan.

 

There are all sorts of tradeoffs. I am going to experiment with ceramic dishes with a lip for this reason.

 

From a practical point of view however, the bowl keeps the ball bearing centered. You can use one set of bowls and a flat upper surface, or invert the bowls for even better stability. That's why the bowls come in sets of 6. Once you have them you can use them as you like.

 

After some back and forth, including my offering to find a cheap supplier for 7075, at the quoted price, 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. This is in my opinion a very good price given the desire to maintain the highest quality -- and in my experience having a better quality 7075 is very valuable.

 

So in any case while I do really like AnotherSpin's design, and all else being equal would use it, Ingress has ordered 1.5" round 7075 stock based upon the specs I originally gave (what Barry suggested), and so we are limited from a practical point of view to a 1" bowl (leaving 1/4" of material around the bowl).

[YashN]

From a practical point of view however, the bowl keeps the ball bearing centered.

 

There's no benefit for the purpose of isolation that the ball is kept centered. On a flat surface, it could still be off-center and the isolation would remain operational (and optimal).

[jabbr]

There's no benefit for the purpose of isolation that the ball is kept centered. On a flat surface, it could still be off-center and the isolation would remain operational (and optimal).

 

Right. The benefit is for those of us with kids and/or dogs and/or intoxicated friends who might be inclined to roll a speaker or other piece of heavy equipment, right off the stabilizers and onto the floor, thus creating both low frequency vibrations as well and a strong audible shriek from my wife whose self sustaining echos will not be damped by any mechanism discussed here nor known to physics -- it might only response to powerful pharmacologic agents but again, the entirely flat design would not be optimal under the circumstances in my own environment.

[YashN]

Won't happen if there is a curve at the very end.

[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 ?

[jabbr]

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 ?

 

I quoted 1.8mm -- that's actually 1/8 inch depth. section of a 2" sphere. So diameter 2".

 

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.

[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 ?

[Foggie]

I quoted 1.8mm -- that's actually 1/8 inch depth. section of a 2" sphere. So diameter 2".

 

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.

 

Stick with 7075 for sure and don't opt for 6061. Make sure the bowl portion is polished, I wouldn't leave the bowl portion raw cut/unfinished.

 

It's an easy setup/run.