I
heard that when setting up a ping-pong table on Shabbos one must
reverse the order, i.e. first hold the board in the air and then
position the legs, is this true?
No, it
is false and the following will explain why.
The Gemora in Beitza 32b teaches us that certain
keilim when erected on Shabbos must be erected in a backhanded
manner, i.e. different to the way it is normally set up. This is
because when erecting these particular keilim it appears as if
one is making a tent – first the legs and then the roof or cover – and
therefore a variation from the norm is required.
However, this only applies to keilim whose function is similar
to a tent’s. Just as a tent’s inside is utilized for living in, usage
etc, so to keilim whose ‘inside’ or ‘underside’ is used require
a deviation when setting up.
A table, Tosefos
tell us, is not an item whose underside is used and therefore it would
not require deviation from the norm and may be set up in the regular
manner.
Therefore when setting up a ping pong table one may first position the
legs and then place the board on top of the legs.
Do
you have an example of a k’li where the deviation from the norm is
necessary?
The
gemora tells us that one uses the space beneath a bed and the
Rishonim say that it is used for storing shoes or sandals during
the night. (Food is not stored beneath a bed because an unclean
ruach descends upon the food). However, Tosefos says that
although the underside is used, since it is not the primary reason for
setting up the bed, one need not change from the norm unless the bed
has two sides (headrest and footrest for example) that either reach
the floor or are within three tefachim
from the floor.
In such
a case one must first hold the board in the air and then slide the
legs in underneath. Since it is setup in an awkward manner one will
remember that tent erecting on Shabbos is forbidden and will not erect
a tent.
What about setting up a bench on Shabbos?
It has the same
halacha as a table, because a bench’s underside is not used
either.
What is the halacha regarding the use of barrels as table legs when
the barrel is being covered by the board?
This
issue is based on the previous one. The Taz says that covering
a four-sided k’li automatically accredits it as a usable space
and requires a deviation from the norm. Since a barrel has four sides,
when using it as table legs one must hold the board in place and then
slide in the barrel.
The
Shulchan Aruch HaRav
disagrees with the Taz and permits erecting a table even when
it has four sides but the Mishna Berura
paskens like the Taz.
Does it make a difference
whether the legs were already in position?
A
crucial point. The Mishna Berura
says that one is only required
to vary from the norm when one first positions the legs and then
places the top but if the legs were already in position and one is
merely placing the top, no deviation is necessary.
This is
because Chazal required a deviation from tent building, which
is usually accomplished by positioning the sides and placing the roof.
In this case it does not resemble tent building and hence no need for
the deviation.
Is there a problem
covering a wide bath or tub on Shabbos?
In
yeshiva there used to be a large, wide tub on wheels which was used
for storing the bread and challa used for Shabbos. The Shulchan
Aruch
says that when covering a large tub one must make sure that he does
not completely cover the tub. Another way around the problem is if the
contents of the tub reach the top, because an ohel is fashioned
when there a space of at least a tefach3 (squared)
is covered, but when the contents reach the top an ohel is not
formed, thereby sidestepping the entire issue.
