Anti vibration grommets

Use ordinary grommets - about half inch diameter. To mount them stand them on edge (like balancing a coin) and fix them to both top and bottom chassis using small P clips. Mount them all at right angles to each other and they won't fall over and lie flat.

Ian

a friend of mine had a similar problem on some V72 amps where the existing mounts had perished. He got some replacements from Maplins - I don't know the part number though. They are a small rubber mount with a M3 screw in each end.

Cheers

Mike

Ian Bell Inscribed thus:

If you only want a few, and are happy with salvage, then a scrap CD rom drive will provide what you want !

There are a bunch of possibilities depending on the mass of the board. The easy one is to take rubber grommets of the sort that appliances use for power cables, and just run a bolt through them. Those should be available from a local hardware store.

It gets much fancier from that point, up to suspended shock mounts like the folks at

--scott

"Just any rubber" will not dampen vibrations. What you want is named Sorbothane (at least in the US).

Good luck ~

Maybe check with Wallace? ;-)

Cheers! Rich

One useful possibility: Well-Nuts. They're T-shaped rubber bushings, with a small nut cast into the end of the stem. Very convenient and easy to use.

Thanks for that. I found this on their web site:

I have asked them what they are mode of and what size they are. Thanks for the tip.

Cheers

Ian

Yes, that had occured to me but the trouble is the bolt is not really tightened and may come loose in use or more likely during shipping - and you know of my recent shipping experience.

I was thinking more of the grommets with a built in cylindrical hollow metal shaft so you could bolt down tightly to the shaft but the PCB would be suspended from the outer diameter of the grommet. I am suire I have seen these in old wireless sets.

That's more like it. Their miniature buffers look very interesting. Thanks for that.

Cheers

Ian

They look really good, but the smallest I have found so far is M5.

Cheers

Ian

Right, you slip a piece of tubing over the bolt, then tighten the bolt down over the tubing.

A lot of that stuff used to show up on the surplus market around here. I suspect if you can find a place where people still do manufacturing work that there is a lot of it.

--scott

I found their web site, don't seem to have a UK distributor though - interesting none the less - I downloaded their brochure.

Thanks for the tip.

Cheers

Ian

Hmmm, that might work really well. Just make the tubing slightly shorter than the thickness of the grommet so it gets compressed slightly. Now I just need a source of tubing.

Cheers

Ian

I don't know if Sorbathane comes in different varieties. The stuff I know is fairly stiff and not good for lightweight items. I like using the black foam rubber used for insulating pipes. Not the Polyethylene stuff, but the stuff that is very soft and does not spring back real fast. Kind of gummy. You can cut it up as desired. Try plumbing or home depts.

greg

Sorbothane is a urethane polymer. You can order it in a whole bunch of different durometers. I don't know that it's better than any other urethane rubber, but they have outrageously good marketing.

That's a urethane foam.... the air in it changes the properties a lot, though.

--scott

:Scott Dorsey wrote: :> Ian Bell wrote: :>> Scott Dorsey wrote: :>>> Ian Bell wrote: :>>>> I ant to mount a tube mic pre PCB on some anti vibrations grommets to :>>>> reduce microphony. Anyone know of a UK source of these? :>>> There are a bunch of possibilities depending on the mass of the board. :>>> The easy one is to take rubber grommets of the sort that appliances use :>>> for power cables, and just run a bolt through them. Those should be :>>> available from a local hardware store. :>> Yes, that had occured to me but the trouble is the bolt is not really :>> tightened and may come loose in use or more likely during shipping - and :>> you know of my recent shipping experience. :> :> Right, you slip a piece of tubing over the bolt, then tighten the bolt down :> over the tubing. :> : :Hmmm, that might work really well. Just make the tubing slightly shorter :than the thickness of the grommet so it gets compressed slightly. Now I :just need a source of tubing. : :Cheers : :Ian

A good source of brass tubing is your local model car/aeroplane hobby shop. For example

You can also get decent nut-locking adhesive from the same source to prevent nuts coming off.

Those shock mounts are easily purchased in Silicon Valley surplus shops. but I have to say they are not very "wiggly." I would look for silicone grommets.

My local ACE Hardware stocks "hobby" sizes of brass tubing. Also Michael's, a craft store.

...Jim Thompson

Yesterday we had a rep drop by from EAR

who dropped off a really cool sample kit of grommets and pull-through fasteners for mounting disk drives and fans. He also gave us a golf ball molded from one of their plastics. Drop it onto a tabletop and it just goes thud, no bounce. They also have some thin sheets of dead-soft foam-like fabric.

Try to wrangle their C-1000 sample kit.

John