Re: I need a swivel or bearing for a lazy susan style turntable.
Patriarch
news:m0gh51dljki20dbc8...@4ax.com:
>
> I can't find anything to solve my problem because I obviously don't
> know how to explain my problem.
> I want the be able to spin by hand a heavy 24" round turntable on top
> of my workbench using centrifugal force. Like the wheel on a car but
> horizontal.
>
> I was going to make it out of 4 inches of MDF but I can't find a
> bearing or swivel or anything that will allow this top spin
> horizontally. Lazy susans are strong and stable but don't allow a
> friction free spin.
>
> I'm sure what I need is out there but I have no idea what it is, or
> what it's called.
>
> There are all sorts of bearing to spin stuff vertically, isn't there
> one I can attach to this table that doesn't cost hundreds of dollars.
>
>
Larry Jaques suggested that this was very similar to a potter's kick wheel.
Try a pottery (ceramics) supply house.
In a former life, a long time ago, I could slam 25+ lbs of stoneware clay
on a wheel head, and throw very large vessels, which were almost impossible
to fire successfully. The hardware held up, though.
http://www.leslieceramics.com/
These folks were the best in my area.
Patriarch
Wilson Lamb
Tell us how much weight you want to carry.
Wilson
<Bla...@address.invalid> wrote in message
news:m0gh51dljki20dbc8...@4ax.com...
GH
> I want the be able to spin by hand a heavy 24" round turntable on top of my
> workbench using centrifugal force. Like the wheel on a car but horizontal.
If I understand your problem correctly, you're concerned that a lazy
susan bearing won't take side thrust and may not stand up to continuous
high-speed use.
How about splitting the problem into two parts -- use 3 or 4 skateboard
bearings mounted around the edge of the turntable to carry the weight,
use another 1 or 2 on the axle to take the side thrust.
--
GH
WillR
> I can't find anything to solve my problem because I obviously don't know how to
> explain my problem.
> workbench using centrifugal force. Like the wheel on a car but horizontal.
>
> swivel or anything that will allow this top spin horizontally.
> Lazy susans are strong and stable but don't allow a friction free spin.
>
> I'm sure what I need is out there but I have no idea what it is, or what it's
> called.
>
> There are all sorts of bearing to spin stuff vertically, isn't there one I can
> attach to this table that doesn't cost hundreds of dollars.
>
I checked Lee Valley. Load capacity 100 lbs. on the largest Lazy Susan.
http://www.leevalley.com/wood/page.aspx?c=2&p=44042&cat=1,250,43298,43316
They use roller bearings. Since I was going to suggest this was a roller
bearing application anyway it seems like a good fit... If these are high
quality they should be low friction. Maybe they would work...
Force is acting downward when stopped and mostly horizontal when rotating.
--
Will
Occasional Techno-geek
http://woodwork.pmccl.com
WillR
That was _1000 lbs._ capacity on the largest -- sorry! Please explain
why this would not work. Then maybe people will understand the problem
better.
--
Will
Occasional Techno-geek
Duane Bozarth
...
> Force is acting downward when stopped and mostly horizontal when rotating.
The gravity load doesn't behave any different whether it's spinning or
not...
To OP, what you're application calls for is a "thrust bearing". Lazy
susans or rotating TV, etc., stands are commercially available for 100+
lbs. The large under-counter one Dad and I built for Mom some 30 years
ago now, used the thrust bearings from a small disc--3/4" shaft
available from a good farm implement supply. What their actual load
rating is I'm not sure, but it would easily hold 250-300 lb, I'm sure.
CW
"WillR" <woodwo...@spammers.pmccl.com> wrote in message
news:41a6e.29$MZ2....@news20.bellglobal.com...
Larry Jaques
Bla...@address.invalid spake:
>
>I can't find anything to solve my problem because I obviously don't know how to
>explain my problem.
>I want the be able to spin by hand a heavy 24" round turntable on top of my
>workbench using centrifugal force. Like the wheel on a car but horizontal.
Give us more info. What are you making? Will any forces be at work,
such as a cutting tool or shaping forces from the side? What weight
will be on the table? How much external force will be applied?
>I was going to make it out of 4 inches of MDF but I can't find a bearing or
>swivel or anything that will allow this top spin horizontally.
>Lazy susans are strong and stable but don't allow a friction free spin.
Hmm, lazy susans don't don't much force to spin, even with 200# on
'em.
For a close-to-friction-free unit, mount a cut-off truck axle (with
bearing and wheel) to a metal frame and put an MDF (or real wood) top
on it.
--
STOP LIVING LIKE VEAL
-----------------------
http://diversify.com Veal-free Websites
lgb
Bla...@address.invalid says...
> Lazy susans are strong and stable but don't allow a friction free spin.
>
perpetual motion machine :-).
But seriously folks, it's hard to find a lower friction coeffecient than
a lubricated ball bearing.
I just bought a lazy susan that's a large circle with said bearings and
it's rated for 1000 pounds. Readily available at Ace hardwares, or
cheaper online if you have other stuff to share the shipping cost.
--
Homo sapiens is a goal, not a description
Robatoy
Bla...@address.invalid wrote:
> I'm sure what I need is out there but I have no idea what it is, or
what it's
> called.
Think air. Use a regular bearing for centre-ing and an air cushion to
elevate.
Perfboard with some routed out channels and a regulator. Over a large
enough area, you'll be able to move tonnage with absolutely no effort
and the regular ball bearing will keep things in place.
10's of thousands of pounds, I tell ya. Four 12" diameter pucks moved a
buddy's printing press like it was floating on air...waitasec..it darn
well WAS floating on air.
You know how they stopped it from moving?
Yup... turned off the air.
btw...the compressor they were using was a 3 HP, 20-30 gallon tank. it
wasn't working that hard.
You only need a little air to get lift...more air does nothing.
Did I help ya? Huh? Huh?
WillR
> Lazy susans are not designed for horizontal forces and LV has suggested against
> it. They are designed to turn, not spin.
> I need something like a utility trailer wheel support only horizontal.
>
Since the lazy Susan has a race of ball bearings it will handle side
forces. I checked that. Besides. after doing a quick mental design and
realizing it would be a lazy Susan anyway... I checked Lee Valley and
the design they stock is exactly what I would have built anyway -- maybe
with larger bearings -- but you are not moving that much weight...
What the heck -- other than the air bearing surface suggested by
Robatoy, nothing obvious now comes to mind. And BTW -- I use an air
baring surface on the side of my table saw. It is quite effective for
heavy sheets of MDF -- saves having to get help to saw large sheets..
Have fun.
--
Will
Occasional Techno-geek
Hax Planks
> Lazy susans are not designed for horizontal forces and LV has suggested against
> it. They are designed to turn, not spin.
> I need something like a utility trailer wheel support only horizontal.
You could just get some car (or truck) bearings from any auto parts
store. They are cone bearings that support the spin in both directions.
A few dollars is all they cost. Still, I think the lazy susan bearings
would work very well. If your disc is centered and reasonably balanced,
there will be no horizontal forces worth worrying about. Since the disc
is symmetrical, the centrifugal forces cancel out and all you have left
is gravity. Believe it or not, it's true.
Wilson Lamb
Have the axle welded in the center of a 1/4" plate of whatever size you
want. Cut off the axle to pit the hub as low as possible, before welding .
Or drill the plate to let the axle go through and then weld at the
appropriate height. Drill another plate, or maybe your wood, to bolt up
where the wheel would ordinarily go. I think you can find a hub with no
studs in it or maybe press the studs out of one that comes with studs. Then
you can use long bolts to hold the wheel on the hub.
The weak point of all this is that the normal hub diameter is relatively
small conpared to the table width, so the table must be pretty rigid. Come
to think of it, you could use a regular rim as the base of your table, if
that doesn't put you too far above the bench. Four little J bolts could
hold a plywood table to the top of the rim. You could fill the rim with
shot to raise its inertia.
Wilson
<Bla...@address.invalid> wrote in message
> On Sun, 10 Apr 2005 08:08:08 -0700, Larry Jaques
> <novalidaddress@di\/ersify.com>
> wrote:
>
>>On Sat, 09 Apr 2005 23:10:28 -0700, the inscrutable
>>Bla...@address.invalid spake:
>>
>>>
>>>I can't find anything to solve my problem because I obviously don't know
>>>how to
>>>explain my problem.
>>>I want the be able to spin by hand a heavy 24" round turntable on top of
>>>my
>>>workbench using centrifugal force. Like the wheel on a car but
>>>horizontal.
>>
>>Give us more info. What are you making? Will any forces be at work,
>>such as a cutting tool or shaping forces from the side? What weight
>>will be on the table? How much external force will be applied?
>>
> want
> to use the weight to keep it spinning.
>
>>
>>>I was going to make it out of 4 inches of MDF but I can't find a bearing
>>>or
>>>swivel or anything that will allow this top spin horizontally.
>>>Lazy susans are strong and stable but don't allow a friction free spin.
>>
>>Hmm, lazy susans don't don't much force to spin, even with 200# on
>>'em.
>>
>>For a close-to-friction-free unit, mount a cut-off truck axle (with
>>bearing and wheel) to a metal frame and put an MDF (or real wood) top
>>on it.
>
> Auto wreckers won't do it and they want a minimum of $250 for the hub off
> anything.
> I can buy an entire utility trailer kit for less.
> But I was hoping to find a nice floor flange (like on single pedestal
> table) and
> a center bearing that might work.
>
>
Patriarch
news:mlni51tgeiu60pbrk...@4ax.com:
> On Sun, 10 Apr 2005 02:42:41 -0500, Patriarch
> <gma...@nospam.comcast.dot.net> wrote:
>
>>Bla...@address.invalid wrote in
>>news:m0gh51dljki20dbc8...@4ax.com:
>>
>>>
>>> I can't find anything to solve my problem because I obviously don't
>>> know how to explain my problem.
>>> I want the be able to spin by hand a heavy 24" round turntable on
>>> top of my workbench using centrifugal force. Like the wheel on a car
>>> but horizontal.
>>>
>>> I was going to make it out of 4 inches of MDF but I can't find a
>>> bearing or swivel or anything that will allow this top spin
>>> horizontally. Lazy susans are strong and stable but don't allow a
>>> friction free spin.
>>>
>>> I'm sure what I need is out there but I have no idea what it is, or
>>> what it's called.
>>>
>>> There are all sorts of bearing to spin stuff vertically, isn't there
>>> one I can attach to this table that doesn't cost hundreds of
>>> dollars.
>>>
>>>
>>
>>Larry Jaques suggested that this was very similar to a potter's kick
>>wheel.
>
> Kicking a wheel on top of a 36" work bench could be tough. I'm just
> not that limber any more.:)
> I need something that can rest on the bench, not the floor.
>
>
Sorry, I wasn't clear. I was under the impression you were looking for
bearings that could handle both a heavy vertical load, as well as side
loading. I understood that the turntable would likely be motor-driven
in some manner. My thought was that the bearings used for a potter's
kick wheel would be suitable, not that you actually use that
configuration.
I wish you well with your quest.
Patriarch
J. Clarke
Assuming it's balanced and he doesn't apply any side force.
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Hax Planx
> Assuming it's balanced and he doesn't apply any side force.
The lazy susan bearing will tolerate some side force. I just don't
think he will have a problem with it since the disk isn't that big or
heavy. He said he had a 12" LS bearing. That should be massive
overkill for his purposes.
Ozoned
I can't find anything to solve my problem because I obviously don't
know how to
> explain my problem.
> I want the be able to spin by hand a heavy 24" round turntable on
top of my
> workbench using centrifugal force. Like the wheel on a car but
horizontal.
>
> I was going to make it out of 4 inches of MDF but I can't find a
bearing or
> swivel or anything that will allow this top spin horizontally.
> Lazy susans are strong and stable but don't allow a friction free
spin.
>
> I'm sure what I need is out there but I have no idea what it is, or
what it's
> called.
>
> There are all sorts of bearing to spin stuff vertically, isn't there
one I can
> attach to this table that doesn't cost hundreds of dollars.
One of these
in your desired rating and a little modification and there you go.
:)
Andy Dingley
<woodwo...@spammers.pmccl.com> wrote:
>Since the lazy Susan has a race of ball bearings it will handle side
>forces
I've never seen a Lazy Susan that would handle side loads. They're a
simple thrust bearing with pressed steel races. There's no sideways
location of the two races, so any sideload tends to lift the upper
race off the balls and then shift the two races relative to each
other, jamming them.
It's not a good practice to put a sideload through any pure thrust
thrust bearing,. But if you must do it, use one with deep races, not
the cheapest of pressed races.
If you have space, the easiest solution is a car hub. They're
enormously over-engineered for this task, so you can simply ignore the
direction of the applied thrust.
John Flatley
I may be missing a few appends to your posting, but I still do not have a
picture of what you are trying to do.
You want to spin by hand, not turn, a 24" diameter, 4" thick MDF turntable
located on your workbench. And you want it to spin this turntable with
something unknown on it, at some unknown rpm for some unknown period
of time.
Although I've seen a number of solutions offered, I submit to you that if
you
describe in some detail what you are trying to accomplish with your
turntable,
you will give the talented folks in this group a clearer picture of your
problem
and they will come up with workable ideas and maybe even the answer to
your 'prayers.'
Jack
--
<Bla...@address.invalid> wrote in message
news:m0gh51dljki20dbc8...@4ax.com...
World Traveler
the stand on which the plate sat. I mounted a large dowel to the back of
the revolving plate, and then recessed the bearings from the front wheel of
a bicycle into the stand., with a similar bearing set at the bottom of the
column into which the dowel sat, This gave a very smooth and sturdy support
to the plate, which turned easily with the touch of the hand.
<Bla...@address.invalid> wrote in message
news:gpjj51d8grj5kf0v2...@4ax.com...
> On Sun, 10 Apr 2005 20:44:33 -0400, "John Flatley" <jfla...@fdn.com>
> wrote:
>
>>BlairR,
>>
>>I may be missing a few appends to your posting, but I still do not have a
>>picture of what you are trying to do.
>>
>>You want to spin by hand, not turn, a 24" diameter, 4" thick MDF turntable
>>located on your workbench. And you want it to spin this turntable with
>>something unknown on it, at some unknown rpm for some unknown period
>>of time.
>>
>>Although I've seen a number of solutions offered, I submit to you that if
>>you
>>describe in some detail what you are trying to accomplish with your
>>turntable,
>
> for as
> long as possible while supporting about 100 pounds.
>
> Replace the wheel and tire on a utility trailer, or a car or truck with a
> heavy
> table the same size as the tire turn it on edge so it is horizontal and
> give it
> the ability to sit in or on a work bench and it would work great.
>
> I can get the hub, and the bearing.
> But getting the part the bearing sits in and fastening that to a work
> bench is
> beyond my ability and rather costly.
> I was hoping there was a product out there that would do this.
> I can find all kinds of shafts and bearings to spin a vertical disk like
> grinding stones but nothing that will support a horizontal disk.
>
>
J. Clarke
> On Sun, 10 Apr 2005 20:44:33 -0400, "John Flatley" <jfla...@fdn.com>
> wrote:
>
>>BlairR,
>>
>>I may be missing a few appends to your posting, but I still do not have a
>>picture of what you are trying to do.
>>
>>You want to spin by hand, not turn, a 24" diameter, 4" thick MDF turntable
>>located on your workbench. And you want it to spin this turntable with
>>something unknown on it, at some unknown rpm for some unknown period
>>of time.
>>
>>Although I've seen a number of solutions offered, I submit to you that if
>>you
>>describe in some detail what you are trying to accomplish with your
>>turntable,
>
> I want to spin a heavy turntable 24" across. I want it to spin easily and
> for as long as possible while supporting about 100 pounds.
Do you want to do this because spinning a heavy turntable 24" across
supporting 100 pounds gives you a woody, or is there some higher purpose to
it? In other words is spinning the turntable your ultimate goal or is the
turntable a means to an end? If it's a means to an end perhaps if you
described that end you might get more useful advice.
> Replace the wheel and tire on a utility trailer, or a car or truck with a
> heavy table the same size as the tire turn it on edge so it is horizontal
> and give it the ability to sit in or on a work bench and it would work
> great.
>
> I can get the hub, and the bearing.
> But getting the part the bearing sits in and fastening that to a work
> bench is beyond my ability and rather costly.
> I was hoping there was a product out there that would do this.
> I can find all kinds of shafts and bearings to spin a vertical disk like
> grinding stones but nothing that will support a horizontal disk.
--
George
<Bla...@address.invalid> wrote in message
news:gt0k519eqgoi2kbre...@4ax.com...
> I want to be able to spin 100 pounds items on a 24" wide turntable that
will
> spin freely as long as possible.
>
>
Tapered roller bearings, as you and others keep mentioning, are ideal. Buy
trailer spindles and bearings from some place like Northern and use 'em.
J. Clarke
> Does knowing what I plan to use it for give you a woody?
No, knowing what you plan to use it for helps me figure out what would be a
suitable design. And designing things _does_ give me a woody.
If you went to an engineer and asked for an estimate on the cost to design
such a thing, whatever he came up with would be at least doubled due to
"lack of definition".
> I want to be able to spin 100 pounds items on a 24" wide turntable that
> will spin freely as long as possible.
Are these items symmetric or asymmetric? Balanced or unbalanced? How many
RPM do you want? Is most of the mass distributed in the center, around the
rim, uniformly, or what? Will there be any lateral force applied to the
object, if so how much lateral force? How long do you need to spin the
object? Is there an objection to powering it this device? Is there any
possibility that the object being spun will shift during operation? Have
you given any thought to retention? Are you going to be performing cutting
operations of any kind on the device being spun? Painting? Anything else?
What's your budget for this? What do you have already that might be
reused?
Is there a college near you? If so visit the library and find a book on
machine design and read it through. Then perhaps you'll understand why
you're being asked for more definition.
Tom
>> I can get the hub, and the bearing.
>> But getting the part the bearing sits in and fastening that to a work
>> bench is beyond my ability and rather costly.
>> I was hoping there was a product out there that would do this.
You can buy hub units that have the lug bolts on one side and a four
bolt flange on the other allowing you to mount both sides - one to a
base and the other to the turning table. Would this work for you?
WillR
Very well put.
I grew to hate high tech and engineering because of sloppy problem
definitions.
Nice/bad to see it wasn't only high tech that suffered from these problems.
Usually after I was awarded a job I would talk to the customer and say
something along the lines of "OK now -- lets nail down all the
specifics..." Then I would be told -- "you're the expert -- figure out
what we want -- we don't have any more time to put into this". Then
..."Let us know when you have it working -- then we'll test it and tell
you if we like it". Then "If it isn't up to standard you can fix it at
your own cost cause you should'a been able to figure it out...".
Not all at once mind you -- just in dribs and drabs as it was revealed
to you the pickle you'd got yourself into.
ROTFLMAO
--
Will
Occasional Techno-geek
George
<Bla...@address.invalid> wrote in message
news:cs5l51tp68mfbiiau...@4ax.com...
> On Mon, 11 Apr 2005 07:16:51 -0400, "George" <george@least> wrote:
>
> >
> ><Bla...@address.invalid> wrote in message
> >news:gt0k519eqgoi2kbre...@4ax.com...
> >
> >> I want to be able to spin 100 pounds items on a 24" wide turntable that
> >will
> >> spin freely as long as possible.
> >>
> >>
> >
> >Tapered roller bearings, as you and others keep mentioning, are ideal.
>
attached
> to the vehicle. If I could find this as a one piece assembly I would.
Unquestionably Confused
>
> None of you gave me any help you moron.
> I already had a solution.
> A hub from a utility trailer bolted to my work bench.
> I was looking for a 'ready to wear' more elegant solution in a bearing assembly.
> Something already out there.
> Lee Valley had already said a lazy susan bearing would not work but that didn't
> stop some of you from insisting they were wrong.
>
> BTW you putz I hold 3 patents that have paid me over $12,000 dollars in the past
> ten years. Peanuts for sure but it isn't my job, it a result of always trying to
> make my hobbies more efficient.
> I'm a hobby woodworker and gardener, and full time computer tech, not a pretend
> engineer like some of you morons.
>
> So piss off. I politely gave all the information needed to explain my problem.
> Then I was insulted because I wouldn't give you detailed plans of my end use.
> You don't need to know my end use to answer the question.
>
> I have a welding shop attaching a flange to the axle stub of a utility trailer
> hub assembly right now.
> It is perfect for my needs, no thanks to this group of ignoramuses.
It's really a shame that some folks have to get testy like this when
they toss out a plea for help to a group of "unknowns."
It's also a shame that when folks attempt to help them, take the time to
"really get into the problem" in an effort to help are thwarted or,
worse yet, ridiculed by the very person they sought to help simple
because they 1) chose to share their personal experiences, 2) asked more
questions so as to make an informed suggestion or 3) had the audacity to
suggest that perhaps a clerk at a woodworking supply emporium - even one
as well thought of as Lee Valley - MIGHT not be endowed with infallibility.
As for that, perhaps you gave Lee Valley more information than you gave
us. Maybe you didn't ask them at all? I realize that the above
information may have been "snipped" but I find it difficult to believe
they would tell you it wouldn't work since they have a numnber of "lazy
susan" devices that will handle up to 1,000 lbs and could be had in a
size that would rival the size of the turntable itself albeit at a loss
of capacity in that it would only hold 660 lbs.
I'm glad you found something perfect for your needs. Did it include a
gift certificate to a Dale Carnegie Course or a class in effective writing?
Plonk!
Larry Jaques
Bla...@address.invalid spake:
>On Sun, 10 Apr 2005 23:28:01 -0400, "J. Clarke"
><jclarke...@snet.net.invalid> wrote:
>>> I want to spin a heavy turntable 24" across. I want it to spin easily and
>>> for as long as possible while supporting about 100 pounds.
>>
>>Do you want to do this because spinning a heavy turntable 24" across
>>supporting 100 pounds gives you a woody, or is there some higher purpose to
>>it? In other words is spinning the turntable your ultimate goal or is the
>>turntable a means to an end? If it's a means to an end perhaps if you
>>described that end you might get more useful advice.
>>
>Does knowing what I plan to use it for give you a woody?
With an attitude like that, you don't deserve any more help from any
of us. Whadda maroon.
--
STOP LIVING LIKE VEAL
-----------------------
http://diversify.com Veal-free Websites
Jeff Cooper
> I hold 3 patents
Just curious, what patents do you hold?
Jeff
Unquestionably Confused
> tripping bozos with only enough knowledge to be dangerous, and NO experience.
>
> HAND
JOB?
lgb
Bla...@address.invalid says...
> If it's a means to an end perhaps if you
> >described that end you might get more useful advice.
> >
>
> spin freely as long as possible.
>
you're going to use it for. Is it illegal? Or just embarrassing? Or
are you just being obstinate?
--
Homo sapiens is a goal, not a description
John Flatley
I along with several other folks have asked you for more information is
various ways. Your apparent refusal to discuss your project in terms of
objectives and to provide any meaningful detail suggests that you may be
working on a project you want to patent. There may be another reason, but
it escapes me.
I wish you luck in your search for a solution to your 'problem!'
Jack
If you are working on a patentable activity, you might consider enrolling in
an Effective Communication 101 course at a local school to assist you with
future projects.
<Bla...@address.invalid> wrote in message
news:gpjj51d8grj5kf0v2...@4ax.com...
> On Sun, 10 Apr 2005 20:44:33 -0400, "John Flatley" <jfla...@fdn.com>
wrote:
>
> >BlairR,
> >
> >I may be missing a few appends to your posting, but I still do not have a
> >picture of what you are trying to do.
> >
> >You want to spin by hand, not turn, a 24" diameter, 4" thick MDF
turntable
> >located on your workbench. And you want it to spin this turntable with
> >something unknown on it, at some unknown rpm for some unknown period
> >of time.
> >
> >Although I've seen a number of solutions offered, I submit to you that if
> >you
> >describe in some detail what you are trying to accomplish with your
> >turntable,
>
> I want to spin a heavy turntable 24" across. I want it to spin easily and
for as
> long as possible while supporting about 100 pounds.
>
> Replace the wheel and tire on a utility trailer, or a car or truck with a
heavy
> table the same size as the tire turn it on edge so it is horizontal and
give it
> the ability to sit in or on a work bench and it would work great.
>
> I can get the hub, and the bearing.
> But getting the part the bearing sits in and fastening that to a work
bench is
> beyond my ability and rather costly.
> I was hoping there was a product out there that would do this.
J. Clarke
Then there are the companies that have learned the hard way about lack of
definition and overreact. I remember one fairly small job we did for
Boeing (you could hold the part in one hand and it was all fabric) where we
had to hire a guy to keep track of the spec revisions and clear out an
office to hold it all--this was in the days before electronic
distribution--the spec arrived on a pallet.
> ROTFLMAO
J. Clarke
> On Mon, 11 Apr 2005 07:00:18 -0400, "J. Clarke"
> <jclarke...@snet.net.invalid> wrote:
>
>>> I want to be able to spin 100 pounds items on a 24" wide turntable that
>>> will spin freely as long as possible.
>>
>>Are these items symmetric or asymmetric? Balanced or unbalanced?
>
> Yes.
So one should assume that the 100 pounds will be a point mass at 12 inches
from the center?
>
>>How many
>>RPM do you want?
>
> As many as humanly possible.
Since you don't say anything about a retention I'm assuming that you are
simply going to lay this point mass on the rim of your platform and allow
friction to hold it. If that is not a valid assumption then please
describe the retention.
To a first approximation and in the absence of any information about the
mating material, the coefficient of friction of of any wood, according to
the Wood Handbook, may be assumed to be .3 as a lower bound. That means
that a 30 pound force will move your 100 pound mass off the table. Using a
safety factor of 1.5, which is a very low safety factor typical of aircraft
design, and if I've run my numbers properly that translates to about 24
RPM. Is that fast enough? If not then there is no point going on with
this until you provide either a number or more definition.
>>Is most of the mass distributed in the center, around the
>>rim, uniformly, or what?
>
> Both.
Then again one must assume a point mass at the rim and the above analysis
applies.
>>Will there be any lateral force applied to the
>>object, if so how much lateral force?
>
> As much as you could apply with a stiff paint brush or rubber spatula.
If the rubber spatula that I just broke is a fair sample that's about 5
pounds.
>>How long do you need to spin the
>>object?
>
> Until I'm finished. The fewer times I have to spin it up the better.
And how long will that be?
>>Is there an objection to powering it this device?
>
> Cost. I need this to spin 10-20 minutes once a day 4 days a week.
Why didn't you just say that you needed it to spin 10-20 minutes in the
first place? Is that so difficult?
>>Is there any
>>possibility that the object being spun will shift during operation?
>
> No.
>
> As I have stated, a wheel hub assembly off a motor vehicle or utility
> trailer would probably be perfect.
> Getting a suitable one has proven to be a problem.
> Not being a welder it's also expensive.
> I didn't expect or ask anyone to design anything.
Well, actually you did whether you realize it or not.
> I was hoping there might be a bearing assembly 'off the shelf' that might
> do this.
There probably is. Have you looked in the McMaster and Grainger catalogs?
But with the information you've given it's difficult to tell which
particular components would do the job for you.
> Like bearing assemblies for making your own grinders and sanding
> machines only one that supports a horizontal disk.
> If the product doesn't exist I'm back to finding a suitable wheel and hub
> off a motor vehicle.
Robert Bonomi
<Bla...@address.invalid> wrote:
>On Mon, 11 Apr 2005 07:00:18 -0400, "J. Clarke"
><jclarke...@snet.net.invalid> wrote:
>
>>> I want to be able to spin 100 pounds items on a 24" wide turntable that
>>> will spin freely as long as possible.
>>
>>Are these items symmetric or asymmetric? Balanced or unbalanced?
>
>
>>How many
>>RPM do you want?
>
>
>>rim, uniformly, or what?
>
>
>>Will there be any lateral force applied to the
>>object, if so how much lateral force?
>
>
>>object?
>
>
>
>
>>possibility that the object being spun will shift during operation?
>
>
>As I have stated, a wheel hub assembly off a motor vehicle or utility trailer
>would probably be perfect.
>Getting a suitable one has proven to be a problem.
>Not being a welder it's also expensive.
>I didn't expect or ask anyone to design anything.
>only one that supports a horizontal disk.
>If the product doesn't exist I'm back to finding a suitable wheel and hub off a
>motor vehicle.
>
>
Have you considered the swivel mechanism from a _chair_?? or a piano stool?
I just got a catalog from Van Dykes Restorers (www.vandykes.com)
They've got chair assemblies rated for several hundred pounds.
Teamcasa
<Bla...@address.invalid> wrote in message
news:m0gh51dljki20dbc8...@4ax.com...
>
> I can't find anything to solve my problem because I obviously don't know
> how to
> explain my problem.
> I want the be able to spin by hand a heavy 24" round turntable on top of
> my
> workbench using centrifugal force. Like the wheel on a car but horizontal.
>
> I was going to make it out of 4 inches of MDF but I can't find a bearing
> or
> swivel or anything that will allow this top spin horizontally.
> Lazy susans are strong and stable but don't allow a friction free spin.
>
> I'm sure what I need is out there but I have no idea what it is, or what
> it's
> called.
>
> There are all sorts of bearing to spin stuff vertically, isn't there one I
> can
> attach to this table that doesn't cost hundreds of dollars.
Here is how I would do it.
I would drill 3" holes in all but the last (top) piece of MDF. Insert two
or three common single row sealed ball bearings. Mount the shaft on a 12"
square steel plate. Weld it or if no access to a welder, press and swedge
fit. Add a spacer over the shaft to stop the disc from hitting the base
and allow the shaft to reach all ball bearings without touching the top
piece of MDF.
Mount/secure vertically and balance. Re-mount on bench and spin away.
Note: Bearing holes and shaft size are dependant on the size bearing you
buy. Typ. Bearing this general size is $8. Graingers.
Dave
Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
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WillR
> Then there are the companies that have learned the hard way about lack of
> definition and overreact. I remember one fairly small job we did for
> Boeing (you could hold the part in one hand and it was all fabric) where we
> had to hire a guy to keep track of the spec revisions and clear out an
> office to hold it all--this was in the days before electronic
> distribution--the spec arrived on a pallet.
>
>
Pretty funny actually. I have seen that too. Since I won't do gov't
contracts anymore I don't see it very much. I did enjoy your story
tho... LOL
Been in High Tech since 68 -- have never worked for a company that
wasn't all electronic format (of some kind) on the specs and product
definitions -- except clients. So I can't really relate personally --
but it's still funny.
--
Will
Occasional Techno-geek
lgb
Bla...@address.invalid says...
> You're an idiot and a busybody, who has NO answers and no solutions.
> Typical of the depths to which most usenet groups, including this one has sunk.
>
> How's that for communication moron.
>
You've communicated yourself right into my bozo bin.
WillR
> On Mon, 11 Apr 2005 15:35:24 -0400, "J. Clarke"
> <jclarke...@snet.net.invalid> wrote:
>
>
>>Bla...@address.invalid wrote:
>>
>>
>>>On Mon, 11 Apr 2005 07:00:18 -0400, "J. Clarke"
>>><jclarke...@snet.net.invalid> wrote:
>>>
>>>
>>>>>I want to be able to spin 100 pounds items on a 24" wide turntable that
>>>>>will spin freely as long as possible.
>>>>
>>>>Are these items symmetric or asymmetric? Balanced or unbalanced?
>>>
>>>Yes.
>>
>>So one should assume that the 100 pounds will be a point mass at 12 inches
>
>>from the center?
>
> cylindrical items of course. I don't make anything over 100 pounds in one piece.
> I suspect my hub rated at 3600 pounds should be up to the job.:)
>
I would suggest that you re-read John's post again. You are likely
concentrating on the wrong point in his post. Since you aren't saying
that much about the stuff you are doing, one can only guess as he points
out, but the real issue may be whether it will stay on the table or not.
You may want to do a force calculation based on a symmetrical balanced
load (placed at the center), and then estimate forces based on an
unbalanced load -- i.e. on the rim. Somewhere I saw you mention 150 RPM,
and now it is 100 lbs. -- possibly unbalanced -- at the outer edge of a
24 inch rim. As John points out -- you must assume the total weight is
on the rim to do the worst case calculation... I will leave it to the
mechanical engineer in you to worry about the safety issues.
While I could do the calculations I can't be bothered as you seem to be
quite capable of doing them. (Someone might be able to tell us the
velocity of the rim of a 24" diameter circular platform, and the
resultant force of a 100 lb. object. The impulse on a floor if it flies
off a 34" high work bench might be an interesting calculation as well.
:-) Better test it outside. :-) )
The people here are not being dinks -- they are pointing out that you
may have missed some significant design factors.
My last post on this topic.
Thanks for listening.
--
Will
Occasional Techno-geek
Larry Jaques
Bla...@address.invalid spake:
>On Mon, 11 Apr 2005 09:17:01 -0700, Larry Jaques <novalidaddress@di\/ersify.com>
>wrote:
>
>>On Sun, 10 Apr 2005 22:02:14 -0700, the inscrutable
>>Bla...@address.invalid spake:
>>
>>>On Sun, 10 Apr 2005 23:28:01 -0400, "J. Clarke"
>>><jclarke...@snet.net.invalid> wrote:
--snip--
>>>Does knowing what I plan to use it for give you a woody?
>>
>>With an attitude like that, you don't deserve any more help from any
>>of us. Whadda maroon.
>
>None of you gave me any help you moron.
You gleaned no terminology from any of us, hmmm?
>I already had a solution.
Then why did you post a request in the first place and then
ungratiously bat down over a dozen tips?
>A hub from a utility trailer bolted to my work bench.
>I was looking for a 'ready to wear' more elegant solution in a bearing assembly.
>Something already out there.
Then you should have said so, y'think?
>Lee Valley had already said a lazy susan bearing would not work but that didn't
>stop some of you from insisting they were wrong.
With that much load, they'd take a lot more lateral force than they
would with a light load.
>BTW you putz I hold 3 patents that have paid me over $12,000 dollars in the past
>ten years. Peanuts for sure but it isn't my job, it a result of always trying to
>make my hobbies more efficient.
And I hold no patents but have made that much from my glare guards
in the same amount of time. I'll bet your patents cost you the better
part of that $12k, too.
>I'm a hobby woodworker and gardener, and full time computer tech, not a pretend
>engineer like some of you morons.
That's "Technical GODs" to you, sir. <g>
>So piss off. I politely gave all the information needed to explain my problem.
>Then I was insulted because I wouldn't give you detailed plans of my end use.
>You don't need to know my end use to answer the question.
You're trying to leech free info from us to use to make more money? I
see. Think anyone here will ever answer another of your requests?
>I have a welding shop attaching a flange to the axle stub of a utility trailer
>hub assembly right now.
>It is perfect for my needs, no thanks to this group of ignoramuses.
>
>HAND
Into the bit bucket you go, bubba. Ta!
----------------------------------
VIRTUE...is its own punishment
http://www.diversify.com Website Applications
==================================================
Duane Bozarth
>
...
> Lazy susans are not designed for horizontal forces and LV has suggested against
> it. They are designed to turn, not spin.
> I need something like a utility trailer wheel support only horizontal.
The disc thrust bearing will hold all you need and more...they're quite
common.
Nate Perkins
news:gt0k519eqgoi2kbre...@4ax.com:
...
> I want to be able to spin 100 pounds items on a 24" wide turntable
> that will spin freely as long as possible.
Browse through their online catalog. Lots of ways to do what you describe.
The company is also very good to deal with (standard disclaimer, no
affilitation).
Prometheus
>They are for ergonomic improvements to products used in the gardening industry.
>
>Considering I've flamed several people in this group who obviously have more
>time than brains I can't provide more info than that.
>I don't need confused individuals on my doorstep.
>
>I'm the type of person who drives 'experts' crazy because regardless of how many
>years it's 'been done that way' I'm always looking for a better way.
>
>I use rare earth magnets to hold steel doors open and closed, everyone else uses
>hooks, doorstops and latches...because that's the way it's been done for years.
Boy, you're a real piece of work. My kitchen cabinets have magnets
holding the doors closed- and they were built at least 50 years ago,
judging from the hardware.
If everyone here is so very, very far below your *obviously* advanced
ego... err... I mean intellect, perhaps you should go post elsewhere.
Aut inveniam viam aut faciam
Tom
>Can you point me at one of these hub units on the net so I know what to ask for?
Sure - give me a couple of days - I'm leaving town in a few minutes
and will be back at the end of the week.
J. Clarke
> On Tue, 12 Apr 2005 05:50:57 -0500, Prometheus <none...@business.org>
> wrote:
>
>>My kitchen cabinets have magnets
>>holding the doors closed- and they were built at least 50 years ago,
>>judging from the hardware.
>
> I guess along with reasoning, reading isn't your strong suit.
You know, you'd have a lot more fun if you weren't spring-loaded in the
pissed-off position.
WillR
> Bla...@address.invalid wrote:
>
>
>>On Tue, 12 Apr 2005 05:50:57 -0500, Prometheus <none...@business.org>
>>wrote:
>>
>>
>>>My kitchen cabinets have magnets
>>>holding the doors closed- and they were built at least 50 years ago,
>>>judging from the hardware.
>>
>>I guess along with reasoning, reading isn't your strong suit.
>
>
> You know, you'd have a lot more fun if you weren't spring-loaded in the
> pissed-off position.
>
John:
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).
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)
I ask because my quick calculations gave me a higher figure than the
rating of the hub suggested. Not sure there is any safety factor there,
not even sure that the hub suggested is within "required" spec.
Thanks for the thoughts -- even if you don't reply... :-))
--
Will
Occasional Techno-geek
Tim Douglass
>I use rare earth magnets to hold steel doors open and closed, everyone else uses
>hooks, doorstops and latches...because that's the way it's been done for years.
You mean like the ones you've been able to buy for Oh, maybe 30-40
years? I installed a bunch of those back in '78 or '79. The also used
electromagnetic hold-open latches on the fire doors that were tied to
the heat detectors. As soon as the temp rose all the fire doors would
close.
Just for the books, sometimes a hook or latch is better than a magnet,
they can hold against a direct pull and require a more specific action
to disengage them. Sometimes that is an advantage. Door stops also
have advantages - can a magnet hold the door open half way? Oh, don't
forget cost as well. Engineering involves a lot more than just
determining if something works.
--
"We need to make a sacrifice to the gods, find me a young virgin... oh, and bring something to kill"
Tim Douglass
J. Clarke
> J. Clarke wrote:
>
>> Bla...@address.invalid wrote:
>>
>>
>>> On Tue, 12 Apr 2005 05:50:57 -0500, Prometheus <none...@business.org>
>>> wrote:
>>>
>>>
>>>> My kitchen cabinets have magnets
>>>> holding the doors closed- and they were built at least 50 years ago,
>>>> judging from the hardware.
>>>
>>>
>>> I guess along with reasoning, reading isn't your strong suit.
>>
>>
>>
>> You know, you'd have a lot more fun if you weren't spring-loaded in the
>> pissed-off position.
>>
>
> John:
>
> 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.
> I ask because my quick calculations gave me a higher figure than the
> rating of the hub suggested. Not sure there is any safety factor there,
> not even sure that the hub suggested is within "required" spec.
>
> Thanks for the thoughts -- even if you don't reply... :-))
--
WillR
> WillR wrote:
>
>>J. Clarke wrote:
>>
>>
>>>Bla...@address.invalid wrote:
>>>
>>>
>>>
>>>>On Tue, 12 Apr 2005 05:50:57 -0500, Prometheus <none...@business.org>
>>>>wrote:
>>>>
>>>>
>>-- 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.
Best wishes...
--
Will
Occasional Techno-geek
Derrick
rounded bottom circular channel in the top and bottom MDF. Fill channel
with marbles. I had made one of these using 3/4" plywood approx. 30"
diameter with channel at 24". Can't see why MDF wouldn't work for you.
Don't remember MDF being available when I made that top 20 years ago This
was a TV rotator. (I use for about 8 years never a problem and very little
force needed to turn about 100 lbs. (you could even get the marbles at a $1
store.) This whole project should do the trick and its pretty cheap too.
Good luck.
"Ozoned" <br...@nebnet-dot-net.no-spam.invalid> wrote in message
news:93d6c$4259c218$455da0d2$11...@allthenewsgroups.com...
> > Anonymouswrote:
> I can't find anything to solve my problem because I obviously don't
> know how to
> > explain my problem.
> > I want the be able to spin by hand a heavy 24" round turntable on
> top of my
> > workbench using centrifugal force. Like the wheel on a car but
> horizontal.
> >
> > I was going to make it out of 4 inches of MDF but I can't find a
> bearing or
> > swivel or anything that will allow this top spin horizontally.
> > Lazy susans are strong and stable but don't allow a friction free
> spin.
> >
> > I'm sure what I need is out there but I have no idea what it is, or
> what it's
> > called.
> >
> > There are all sorts of bearing to spin stuff vertically, isn't there
> one I can
> > attach to this table that doesn't cost hundreds of dollars.
>
>
> One of these
> in your desired rating and a little modification and there you go.
> :)
>
WillR
> 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