Inverted bearing questions

[cukkurullo]

Hi Dears,

I would like to build a new table with inverted bearing. Do you know any project of an inverted bearing? How it works with oil and lubrification?

Best Wishes,
Jhon Cukkurullo

[AMV8]

Hi

I do not know of a project with an inverted bearing but I use the townshend rock turntables which have inverted bearings. I will describe that to you.

The centre spindle is connected to the turntable plinth. It is steel and has a hardened steel top that is convex on the top. A hardened steel bearing, I think 10mm, sits on top of that convex surface and forms a point contact. The outer sleeve is connected to the turntable and drops around the centre spindle. The top of the outer shaft has a brass bearing inserted that sits onto the steel bearing. The brass bearing can be unscrewed and replaced if necessary. ( They last at least 10 years )

At the bottom of the centre spindle is an oil bath and the lower edge of the outer sleeve sits in the oil bath and "picks up" oil which rises up the centre spindle and lubricates the bearing and shaft.

The brass bearing, at the top of the outer sleeve, has a bleed hole in the centre and an oil impregnated pad above the brass bearing.

On the rock the centre spindle is a reasonably tight fit inside the sleeve and the sleeve just rotates around the spindle with oil lubricating the contact area - in theory.

The only real wear is at the top of the spindle - even though it is hardened steel. Eventually a hollow forms on the top of the spindle where the bearing is in constant contact and a litttle wear is evident on the side of the spindle at the top, but this is of no real consequence.

A bit difficult to explain but I hope that helps.

Don

[cukkurullo]

Don,


thanks a lot. You pictured the bearing system of your wonderful deck very well. Now I have it in front of my eyes!!

Thanks a lot,
JK

Originally posted by AMV8
Hi


..... A bit difficult to explain but I hope that helps.

Don

[AndrewT]

Hi,
the Michell has a helical groove machined in the spindle.
As the deck rotates, the groove pumps oil to the top (Archimedian screw). There is a hole from top to bottom to allow the oil to circulate from oil bath to top and return. I cannot recall where the return hole is drilled.

Try looking at Michell's site there may be a pic or two.

[Werner]

http://www.geocities.com/michell_gyr...ic/bearing.jpg