OK, all you math wizards, here's one for you:
Given a pedestal table with a top diameter of Dtop, a bottom diameter
Dbottom, and a height H, define a function f() such that
Dbottom = f(Dtop, H).
You can assume that the table is symetrical about the center axis.
For all of you non math wizards, what's a good rule of thumb for
how big to make the base of a pedestal end table approx. 20" tall?
--
Mike McDonald
[email protected]
I was just talking to a buddy who builds desk lamps commercially. We were
discussing design requirements and he said that the UL requires that a desk
lamp can be tilted 70 degrees without falling over.
No, that doesn't apply to a table, but it gives you a good starting point
(ending point?) for your table design.
"Mike McDonald" <[email protected]> wrote in message
news:[email protected]...
> OK, all you math wizards, here's one for you:
>
> Given a pedestal table with a top diameter of Dtop, a bottom diameter
> Dbottom, and a height H, define a function f() such that
>
> Dbottom = f(Dtop, H).
>
> You can assume that the table is symetrical about the center axis.
>
> For all of you non math wizards, what's a good rule of thumb for
> how big to make the base of a pedestal end table approx. 20" tall?
>
> --
>
> Mike McDonald
> [email protected]
Greg Neill wrote:
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]
>> Scott Cox wrote:
>>> I was just talking to a buddy who builds desk lamps commercially. We
>>> were discussing design requirements and he said that the UL requires
>>> that a desk lamp can be tilted 70 degrees without falling over.
>> In that case none of my UL listed desk lamps are UL listed--70 degrees
>> is an awful lot of tilt--that's not in the "desk lamp" realm, that's
>> in the "Weebles wobble but they don't fall down" realm. Heck, I don't
>> know of any _desks_ that will go that far over without falling, let
>> along desk _lamps_.
>>
>> And no, I don't know what the standard says--UL wants more than 300
>> bucks for a copy of it and then it references a few thousand bucks
>> worth of other standards.
>
> Perhaps the angle is measured from the horizontal.
> That way it would have to withstand a 30 degree
> tilt from the vertical, which seems to be more in
> line with the real world.
The physics here is well known: F = ma where m is the mass of the
bottom and a is the angle of the dangle. F is a measure of the
proportionality of the two features held at bay unless it's a goose neck
lamp for which all bets are off. If you are near Philadelphia you must
factor in the fact that all involutory collineations are harmonic
homologies. Hope this helps.
insincerely,
Mr. Mathwizz
Mike,
I posted the same question not long ago.... Here's the link...
jc
http://groups.google.com/group/rec.woodworking/browse_thread/thread/157cee3727d4ccd0/a5e0a13e9ddaa836?lnk=gst&q=pedestal#a5e0a13e9ddaa836
"Mike McDonald" <[email protected]> wrote in message
news:[email protected]...
> OK, all you math wizards, here's one for you:
>
> Given a pedestal table with a top diameter of Dtop, a bottom diameter
> Dbottom, and a height H, define a function f() such that
>
> Dbottom = f(Dtop, H).
>
> You can assume that the table is symetrical about the center axis.
>
> For all of you non math wizards, what's a good rule of thumb for
> how big to make the base of a pedestal end table approx. 20" tall?
>
> --
>
> Mike McDonald
> [email protected]
On Feb 12, 5:50 pm, [email protected] (Mike McDonald) wrote:
> OK, all you math wizards, here's one for you:
>
> Given a pedestal table with a top diameter of Dtop, a bottom diameter
> Dbottom, and a height H, define a function f() such that
>
> Dbottom = f(Dtop, H).
>
> You can assume that the table is symetrical about the center axis.
>
> For all of you non math wizards, what's a good rule of thumb for
> how big to make the base of a pedestal end table approx. 20" tall?
>
> --
>
> Mike McDonald
> [email protected]
you can't reduce table design to a single ratio.
it's an end table, not for seating, so that simplifies things quite a
bit, as you don't need to provide foot/ knee space. if the mass of the
base can exceed the mass of the top by a *significant* margin, and the
diameter to height ratio is large enough you can make the base smaller
than the top by amounts that diminish as the ratios get higher, but
unless there is a real need to do so don't bother. do a weighted mock
up with the base an inch or two smaller in radius than the top and see
how it performs in the proposed location.
and watch out for over intellectualizing furniture design. that way
lies some ugly product.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]=20
> Scott Cox wrote:
>> I was just talking to a buddy who builds desk lamps commercially. We
>> were discussing design requirements and he said that the UL requires
>> that a desk lamp can be tilted 70 degrees without falling over.
>=20
> In that case none of my UL listed desk lamps are UL listed--70 degrees
> is an awful lot of tilt--that's not in the "desk lamp" realm, that's
> in the "Weebles wobble but they don't fall down" realm. Heck, I don't
> know of any _desks_ that will go that far over without falling, let
> along desk _lamps_.
>=20
> And no, I don't know what the standard says--UL wants more than 300
> bucks for a copy of it and then it references a few thousand bucks
> worth of other standards.
Perhaps the angle is measured from the horizontal. =20
That way it would have to withstand a 30 degree=20
tilt from the vertical, which seems to be more in
line with the real world.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]=20
=20
> Not meaning to nitpick but that would be 20 degrees (remember, a right
> angle is 90, not 100). And does make more sense.
Okay, okay, so I can't do math before coffee. :-)
> OK, all you math wizards, here's one for you:
>
> Given a pedestal table with a top diameter of Dtop, a bottom diameter
> Dbottom, and a height H, define a function f() such that
>
> Dbottom = f(Dtop, H).
>
> You can assume that the table is symetrical about the center axis.
>
> For all of you non math wizards, what's a good rule of thumb for
> how big to make the base of a pedestal end table approx. 20" tall?
It's not that simple: Much more detail required.
--
Regards,
PopRivet
Nope, not going to Vista. Why?
Simple: It offers me nothing I need nor
even want that I don't already have.
So, why switch? NOT gonna happen.
On Wed, 13 Feb 2008 00:50:17 GMT, [email protected] (Mike McDonald)
wrote:
> OK, all you math wizards, here's one for you:
>
> Given a pedestal table with a top diameter of Dtop, a bottom diameter
>Dbottom, and a height H, define a function f() such that
>
> Dbottom = f(Dtop, H).
>
>You can assume that the table is symetrical about the center axis.
>
> For all of you non math wizards, what's a good rule of thumb for
>how big to make the base of a pedestal end table approx. 20" tall?
It's not quite that easy. This is a static (mechanical engineering)
problem about moment arms, center of gravity and the force applied to
the edge of the table. Some round tables are sturdier than others.
Scott Cox wrote:
> I was just talking to a buddy who builds desk lamps commercially. We
> were discussing design requirements and he said that the UL requires
> that a desk lamp can be tilted 70 degrees without falling over.
In that case none of my UL listed desk lamps are UL listed--70 degrees
is an awful lot of tilt--that's not in the "desk lamp" realm, that's
in the "Weebles wobble but they don't fall down" realm. Heck, I don't
know of any _desks_ that will go that far over without falling, let
along desk _lamps_.
And no, I don't know what the standard says--UL wants more than 300
bucks for a copy of it and then it references a few thousand bucks
worth of other standards.
> No, that doesn't apply to a table, but it gives you a good starting
> point (ending point?) for your table design.
>
>
> "Mike McDonald" <[email protected]> wrote in message
> news:[email protected]...
>> OK, all you math wizards, here's one for you:
>>
>> Given a pedestal table with a top diameter of Dtop, a bottom
>> diameter Dbottom, and a height H, define a function f() such that
>>
>> Dbottom = f(Dtop, H).
>>
>> You can assume that the table is symetrical about the center axis.
>>
>> For all of you non math wizards, what's a good rule of thumb for
>> how big to make the base of a pedestal end table approx. 20" tall?
>>
>> --
>>
>> Mike McDonald
>> [email protected]
--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Greg Neill wrote:
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]
>> Scott Cox wrote:
>>> I was just talking to a buddy who builds desk lamps commercially.
>>> We
>>> were discussing design requirements and he said that the UL
>>> requires
>>> that a desk lamp can be tilted 70 degrees without falling over.
>>
>> In that case none of my UL listed desk lamps are UL listed--70
>> degrees is an awful lot of tilt--that's not in the "desk lamp"
>> realm, that's in the "Weebles wobble but they don't fall down"
>> realm. Heck, I don't know of any _desks_ that will go that far
>> over
>> without falling, let along desk _lamps_.
>>
>> And no, I don't know what the standard says--UL wants more than 300
>> bucks for a copy of it and then it references a few thousand bucks
>> worth of other standards.
>
> Perhaps the angle is measured from the horizontal.
> That way it would have to withstand a 30 degree
> tilt from the vertical, which seems to be more in
> line with the real world.
Not meaning to nitpick but that would be 20 degrees (remember, a right
angle is 90, not 100). And does make more sense.
--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
In article <425e9e1f-92d9-47a8-8a3a-aecac24b4412@d21g2000prf.googlegroups.com>,
[email protected] writes:
> you can't reduce table design to a single ratio.
True, but there probably are some good rules of thumb to start with.
Off hand, I'm thinking somewhere around 2/3 the top diameter is a good
compromise between stability and asthetics.
Since these end tables will be surrounded on all four sides by walls or
couches, I can lean more towards asthetics. But since the table is
surrounded, the base won't be seen either. The biggest "impact" on stability
will be "Lead Butt", the cat, springboarding off of it.
> it's an end table, not for seating, so that simplifies things quite a
> bit, as you don't need to provide foot/ knee space. if the mass of the
> base can exceed the mass of the top by a *significant* margin, and the
I was assuming (unstated) no lead weights. I was thinking strictly of
uniform density wood construction.
> and watch out for over intellectualizing furniture design. that way
> lies some ugly product.
So true. The whole part about defining f() was bait for the
"intellectuals" who kept trying to teach me trig when I wanted to
know how to cut an octogon. Practical vs theoretical knowledge.
--
Mike McDonald
[email protected]
In article <[email protected]>,
Phisherman <[email protected]> writes:
> It's not quite that easy. This is a static (mechanical engineering)
> problem about moment arms, center of gravity and the force applied to
> the edge of the table. Some round tables are sturdier than others.
You guys can be counted on for a good laugh!
--
Mike McDonald
[email protected]