DIYbanter - View Single Post - I need a swivel or bearing for a lazy susan style turntable.

lid wrote:
On Tue, 12 Apr 2005 14:35:27 -0400, WillR
wrote:

J. Clarke wrote:

WillR wrote:

J. Clarke wrote:

wrote:

On Tue, 12 Apr 2005 05:50:57 -0500, Prometheus
wrote:

I'm curious -- what did you calculate as the side force on the bearing
-- worst case (edge load of 100lb. -- c.o.g. at platform level -- point
mass -- 150 rpm -- 24" disk -- assuming no vibration due to imbalance
i.e. simplest case).

I didn't. I took it as a point mass on the rim secured by friction with
a 1.5 safety factor and got 24 RPM before it falls off and stopped there
until I got confirmation that 24 RPM was sufficient. That was giving 20
pounds lateral load, friction-limited, neglecting any unbalance in the
table itself--I didn't look at the moment.

You seem to be a mech. eng. my specialty is elsewhere -- so not sure I
remember all the stuff I should take into account especially once I
looked at a bit of vibration all bets seemed to be off :-) . (I had to
grab one of my mech eng. books to remind myself of the factors... at
least you can see electrons unlike this mechanical stuff. LOL)

It's been so long since I've actually done ME (computers bit me hard)
that I'd have to dig out the references before I got much deeper into this.

Thanks. I just had a cursory look - but at 150 RPM (since he had
mentioned a motor and 150 RPM in another post) I was a little surprised
at the force on the bearing -- assuming the load was constrained and
didn't fall off... LOL

A little flexing or vibration and it could get interesting. :-)

I had pulled out my ME text and that's why I asked.

Anyway. Not our problem. And not my field.

What a bunch of fools.
Maximum weight 100, Maximum RPM 150.

At no time did I mention spinning 100 pounds at 150 RPM.

Nor did you not.

Or that any of that weight would be anywhere near the edge of the table.
Or that the weight was a single solid object.

Nor did you not.

Even if I did spin a hundred pounds at 250 RPM the worst that would happen is
there would be a big mess.

Hopefully in your lap. :-)

I'm out of this thread. I had enough laughs for this week.

And at no time did we ask you to comment or suggest we were talking
about your machine. So buzz off.

Laughs it was -- but no sense. :-)

Well that was the point wasn't it? That people who gave advice would
look like fools if they could not figure out the conditions under which
the parts would run -- and hence had to assume worst case. Unless you
stated all the specs together.

You said you did not know how to explain yourself -- and clearly you
were correct on that much. As for the rest -- good luck with all your
frankenmachines.

...and that is why it is dangerous to give advice in this group unless
people can lay out clearly what they wanted to know, and what help was
needed and under what conditions.

By responding you helped me make my point.

Thanks for playing and good luck -- one fool to another.

--
Will
Occasional Techno-geek