[frozenpeas]

Hi,
does anyone know what type of bearing is required to support the rotation of a vertical spindle on a turntable that will carry weight.
Ideally I would like it to be able to carry as much weight as possible.

Thanks in advance.

See attached sketch.

[txcncman]

Automotive axle bearings?

[RICHARD ZASTROW]

Depends on a few variables.
1. Speed
2. weight
3. is weight centralized or offset
4. accuracy of rotation
5 "wobble" tolerance
6. will the table be subjected to lifting
and I'm sure there are more.

You might want to look at crossed roller table bearings, they can support quite a bit of weight. They're commonly used in rotary tables.

Dick Z

[frozenpeas]

Automotive axle bearings?

Thanks
I had seen these mentioned elsewhere.

[frozenpeas]

Depends on a few variables.
1. Speed
2. weight
3. is weight centralized or offset
4. accuracy of rotation
5 "wobble" tolerance
6. will the table be subjected to lifting
and I'm sure there are more.

You might want to look at crossed roller table bearings, they can support quite a bit of weight. They're commonly used in rotary tables.

Dick Z

1. Not sure yet but not fast
2. Want this to be as flexible as possible
3. Could be either if possible
4+5. Revolving on a central spindle should be accurate enough, little bit of lateral movement wont matter
6. No I think all the force will be down

Thanks, you got me thinking that maybe I'm going about this the wrong way.
Perhaps I should be supporting the turntable part to take the load with rollers then the load will be on the rollers as opposed to the bearing. Just have to make sure that no one puts a 2 ton 20mm object in the center which would put all the load on the spindle!
Ammended diagram attached.

Although, I'm still not sure of what type of bearing would be most suitable?
Rob

[txcncman]

Maybe you should study the spindle and chuck on a VTL.

[RICHARD ZASTROW]

Many VTL's incorporate crossed roller bearings. These are located where you placed your rollers.

If you would provide answers to the questions in post #3 we could probably give you better recommendations. A range of RPM, weight and diameter would help for starters.

We could suggest bearings for carrying a thousand pounds, 600 RPM and well centered loads such as txcncman suggested as on a VTL. Rather pricey overkill if all you need is a bearing to carry an off-center 1 pound load of feathers.LOL

Your second sketch is very similar to an 1896 Betts VTL now rusting out in front of a machine shop as a memorial of the days of steam powered line shafts.(I'm not quite that old).

Dick Z

[frozenpeas]

As mentioned I'm really not too sure of these figures yet, but for now let's say:

Weight: 80 - 100kg
RPM: between 1 and 10
Diameter: between 600 and 1200mm

Just been reading about tram turntables. I know these are mega heavy duty but surely the principles are similar.
Google SAN FRANCISCO CABLE CAR TURNTABLE REHABILITATION pdf
Very interesting read or am I just sad.

Thanks

[RICHARD ZASTROW]

So that you can become better versed on table type bearings, you should spend some time on the Internet investigating them.

"google" cross roller ring bearings, slew (slewing) rings, table bearings etc. There are ball type, roller type, air bearings, plain bearings of bronze and fluorocarbons (Teflon) etc.

Adequately lubricated plain bearings could easily support 100kg @10 rpm. As long as there is no lifting force that would be an easy, low cost solution. Plain bearings work fine supporting crankshafts in auto engines and grinding machine spindles.

Many machine tool way systems were built on hydrostatic way systems which are plain linear bearings.

Might look into IGUS bearings. (iglide polymer bearings at Igus website)

Dick Z

[bebob1]

whats the application here

so youre looking for bearings that can sustain high axial loads due to the heavy weight of the rotor body and added loads?

for the top bearing, you can use an angular contact bearing and the bottom you can use roller thrust bearing? or you can use two angular contact bearings properly constrained so the rotor is hanging in mid air? If you have super heavy radial loads you can change the bearings to journal bearings and put a roller thrust bearing at the bottom to support the whole thing. depending on how fast and efficient you need to spin it this influences things.

ideally you maybe want the top one to be located angular contact bearing and the bottom just an unlocated roller bearing so the shaft mid section doesn't compress when axially loaded or thermally expanded which can happen if both bearings are axially located. downside is less load capacity for more efficient less wear operation.

[RICHARD ZASTROW]

100 Kg is not a very heavy axial load. 10 rpm is not very fast.

Another simple way to support your platter would be some cam rollers in the place you positioned rollers in your sketch. They are available with eccentric studs that allow adjustment. You could then easily set them all on the same plane.

Just a little more added confusion. LOL

Dick Z