May one stick a rubber suction hook onto a wall on Shabbos?

The initial reaction is to sanction it as it is not attached to a wall with screws or nails. However, it is not so simple.

For two reasons it is forbidden to knock a nail into a wall: firstly the nail will become part of the wall; secondly, it becomes permanent. [1]

It is for this reason the Magen Avraham [2] permits us to hang curtains on a rod on Shabbos, as the curtain does not appear to be part of the wall and is not placed permanently.

But does the Chazon Ish not argue with this Magen Avraham?

Indeed he does. The Chazon Ish [3] argues that hanging a curtain permanently is boneh because it becomes one with the building. (The M”A learns that a curtain is usually not permanent because it is removed for laundering or mending).

But even the Chazon Ish agrees that a curtain loosely hung is not ‘part of the wall’ and may be hung on Shabbos.

What is the situation with respect to a vacuum hook?

Likewise, it would be ossur to permanently affix a vacuum hook to a wall [4] because it is similar to fixing a nail into a wall. The hook is not affixed loosely and ready to be removed, thus both the Magen Avraham and the Chazon Ish agree that it is forbidden.

What about hanging a set of hooks over the top of the door?

Since the hooks are not affixed or attached to the door it is not a problem. Even the Chazon Ish would agree, being that the hooks are not fastened.

A towel hangs from a tube affixed between wall brackets. May one remove the tube on Shabbos?

Some shuls and public places have towels hanging from a bar that is secured between brackets (similar to the toilet paper holder). May one remove the bar to change the towel? On one hand the bar is held between the brackets, which would seem to make it part of the building and its removal is soter - demolishing, but on the other hand it is used in this manner.

Based on the definitions mentioned above, we would say that since the bar is not mevutal (permanently attached) to the brackets, rather its use is to continuously remove and attach it to place and remove towels, it is not boneh or soter. The bar is not intended to be part of the building, just like the “v’tein b’racha” sign is not part of the wall, rather placed on the wall. The Chazon Ish would also agree because by definition it is not part of the wall. [5]

Is it permitted to attach the needle to a syringe on Shabbos?

This action involves the concept of makeh b’patish – making a k’li. A brief introduction: The gemora Shabbos [6] says that assembling a traveling bed is ossur on account of making a k’li. Even though the bed is not assembled in a permanent manner, as it is taken apart and reassembled in another location, it is still ossur.

What is the difference between a traveling bed and a salt shaker?

A salt shaker is opened to refill salt and shut and the Chazon Ish writes that this may be done on Shabbos as well, so seemingly the same should apply to the traveling bed. Indeed the poskim [7] write that the traveling bed was assembled with screws and nails that were driven with force. The chidush is that even though it is assembled and taken apart on a permanent basis, since force and craftsmanship is used in this action, it is ossur. A salt shaker is made to open and shut easily and its assembly does not involve an issur.

The Chazon Ish [8] makes another distinction between the bed and the saltshaker, which carries far fetching ramifications.

One need not take the bed apart in order to use it, on the contrary, taking it apart is contrary to its use, whereas a saltshaker is made to open and close in order to use.

In other words, once the bed is assembled it can be used forever and taking it apart is for a different reason, to travel etc, but not for its use. A jammed saltshaker that cannot open is useless because it requires refilling, so opening and closing is integral to its use.

And the syringe?

Seemingly it is ossur because it is a one-time assembly that creates the k’li. Rav Shlomo Zalman Auerbach explained [9] that attaching two or more parts to make a k’li for a single use and subsequently discarded or taken apart is not makeh b’patish. Only when parts are permanently attached do we say it is makeh b’patish (or when force or craftsmanship or screws are used).

Consequently attaching the needle to the syringe for a single use is not making a k’li. One of his proofs is from the Magen Avraham [10] who writes that on Yom Tov one may not thread string into a needle (to sew a chicken before cooking) because one might cut the string to size etc. Why did he not say that threading the string in a needle is makeh b’patish as now the two can be used as a k’li? He answers that since it is taken apart immediately after use; they are not seen as a single k’li rather as using each other.

This is not an easy subject and before assembling any k’li a rav must be asked. Be”H we will continue this issue in the coming shiurim.