Since the parsha tells us that the Jews were enslaved to perform many construction projects, this is an appropriate week to analyze the halachos of construction on Shabbos.
Question #1: I am having a lot of company for Shabbos and we have a small house. On Friday night, I would like to remove the extra leaves from the table and then set up the “portacrib” in the space that creates, and then, in the morning, fold up the crib and put the table leaves back. May I do this on Shabbos?
Question #2: The lens fell out of my eyeglasses on Shabbos. May I pop it back in?
Question #3: I have an adjustable shtender that I usually leave at the same height. May I adjust it on Shabbos?
Question #4: The house is very crowded and stuffy because we are celebrating a kiddush. May I remove a door or a window to allow some additional ventilation? (I was asked this shaylah in Israel where doors and windows are hinged in a way that they are easily removable.)
Question #5: May I remove the pieces of glass from a broken window on Shabbos?
Before discussing these shaylos, we need to explain the halachos of construction on Shabbos, and how they apply to movable items such as household furnishings and accessories.
CONSTRUCTION ON SHABBOS
Boneh, building or constructing, is one of the 39 melachos of Shabbos. Included in this melacha is performing any type of home repair or enhancement, even only a minor repair (see Shabbos 102b). Thus, it is prohibited min haTorah to hammer a nail into a wall in order to hang a picture (Rashi, Eruvin 102a s.v. halacha). Similarly, one may not smooth the dirt floor of a house because this enhances the “structure” (Shabbos 73b).
Sosair, demolishing or razing, is also one of the 39 melachos, since the Bnei Yisroel disassembled the mishkan whenever they moved from place to place (Shabbos 31b). Therefore, any demolition of a building is prohibited min haTorah if the ultimate results are beneficial, such as the razing of part of a building in order to renovate it.
If there are no benefits to the demolition, it is still prohibited miderabbanan. Thus, wrecking the house out of anger violates Shabbos only miderabbanan (according to most Rishonim) since there is no positive benefit from the destruction (Pri Megadim 314:11 in Eishel Avraham). It is prohibited min haTorah because of other reasons, such as bal tashchis (unnecessary destruction) and being bad for one’s midos (see Shabbos 105b).
We already have enough information to address questions #4 and #5 above, whether one may remove a window to ventilate the house and whether one may remove pieces of glass from a broken window. It would seem that the first case is prohibited min haTorah since it involves the melacha of sosair for positive results. The second case may depend on whether the removal of the broken glass is so that no one hurts himself, in which case this might be prohibited only because of a rabbinic injunction, or whether it is being removed as the first step in the repair, in which case it would be prohibited min haTorah.
If the broken window is dangerous (but not life threatening), I may ask a non-Jew to remove the broken pieces of glass.
CONSTRUCTION OF MOVABLE ITEMS
Do the melachos of boneh and sosair apply to movable items, keilim (sing., kli), as well, or only to buildings? In other words, does the Torah’s prohibition refer only to something connected to the ground, or does it include construction of a movable item?
This question is disputed in the Gemara and by the Rishonim (Beitzah 10a). There are three basic opinions:
1. Keilim are not included in the prohibition of boneh and sosair.
2. Keilim are totally included in the prohibition of boneh and sosair.
3. A compromise position in which total construction or destruction of a kli is prohibited min haTorah, but minor improvement is not (Tosafos, Shabbos 74b and 102b). The halacha follows this opinion (Shulchan Aruch Orach Chayim 314:1).
WHEN DOES BONEH APPLY TO KEILIM?
Assembling or improving a kli in a way that involves strength and skill constitutes boneh, and disassembling it involves sosair. Therefore, it is prohibited min haTorah to assemble a piece of furniture in a way that tightens the pieces since this involves strength and skill to do the job properly. Similarly, replacing the handle on a hoe or other appliance is prohibited min haTorah since it requires skill and strength to do the job properly (Shabbos 102b).
Assembling furniture without tightening the pieces is not prohibited min haTorah, but is prohibited miderabbanan out of concern that one might tighten them (Tosafos, Shabbos 48a s.v. ha; Hagahos Ashri Shabbos 3:23). Therefore, one may not assemble a bed, crib, or table even without tightening the pieces (Kaf Hachayim 313:63).
One may not assemble a crib on Shabbos. Assembling it in a tight way is prohibited min haTorah, whereas assembling it without tightening the pieces is prohibited miderabbanan since one might assemble it tightly.
However, the halacha regarding the setting up of portacribs is lenient, since this does not involve re-assembling. Everything remains attached and the parts are merely straightened out. So they can certainly be opened and closed on Shabbos.
FIXING A BROKEN APPLIANCE
Repairing a broken appliance on Shabbos follows the same guidelines as assembling. Therefore it is prohibited when the repair requires skill and strength even if one repairs it in a temporary way.
Therefore, if the leg of a bed or table fell out, one may not reinsert it even temporarily out of concern that one might repair it permanently (Shulchan Aruch Orach Chayim 313:8). In this instance, Chazal decreed that the bed or table itself becomes muktzah in order to ensure that someone does not repair it (Rema Orach Chayim 308:16).
There are two exceptions to this rabbinic prohibition, when one may assemble or repair an item in a non-permanent way. The first is on Yom Tov where the halacha is that one may use a temporary repair to fix a furniture item for a Yom Tov need (Tosafos, Beitzah 22a; Shulchan Aruch Orach Chayim 519:2, Magen Avraham and Gra ad loc.).
A leg fell off the table on Yom Tov. Repairing the table in a proper way is prohibited min haTorah, and therefore on Shabbos I may not even reinsert the leg into the table in a temporary way. On Yom Tov, however, I may reinsert the leg without performing a proper repair, if this is the most convenient table to use.
If the broken or disassembled item is usually repaired or assembled without strength or skill, I may repair it in a temporary fashion. Chazal did not forbid this since it is unlikely that it will cause any Torah violation (Shabbos 47b with Tosafos).
In the time of the Gemara there existed a type of bed called “a coppersmiths’ bed.” Apparently, it was common that coppersmiths traveled from place to place making their living as iterant repairmen, and took portable beds with them that they reassembled at each destination. May one assemble this bed on Shabbos or is it considered construction? The Gemara quotes a dispute on the subject. According to the Tanna who contends that keilim are totally included in the prohibition of boneh and sosair, one may not assemble these beds on Shabbos (Shabbos 47a).
However, the conclusion of the Gemara is that one may assemble these beds on Shabbos. That is because these beds were never assembled very tightly and therefore it is not considered boneh to construct them, nor does it qualify as a rabbinic prohibition. However, an appliance that is normally assembled very tightly would be prohibited to assemble even loosely since it might be tightened (Tosafos ad loc.).
Inserting table leaves also does not require skill or strength and is therefore permitted on Shabbos. However, some tables have a clamp to tighten the table after inserting or removing the leaf. Some authorities contend that tightening this clamp might be prohibited min haTorah. Those who hold that way will also prohibit adding or removing leaves from these tables on Shabbos, even if one does not tighten the clamp, out of concern that one might tighten it.
THE SCREW – AN INTERESTING INVENTION
About three hundred and fifty years ago, the poskim began discussing appliances held together with screws. Around this time a drinking cup became available where the cup part screwed into a base. Does screwing this appliance together on Shabbos constitute boneh?
The halachic question here is as follows: Although this cup does not require someone particularly strong or skilled to assemble and disassemble, screwing on the base makes the cup into a well-made permanent appliance. Thus, the screw enables someone who is not particularly skilled to build a strong appliance.
The early poskim debate this issue. The Magen Avraham (313:12) rules that screwing an appliance together constitutes a melacha min haTorah (see Shaar Hatziyun 313:32); the Maamar Mordechai disagrees. In practice however, the Maamar Mordechai concludes that one should follow the stringent ruling of the Magen Avraham, and this is the accepted halachic practice. Thus, screwing the cup together is considered manufacturing a cup.
Similarly, today you can purchase furniture that you take home and assemble by yourself. Assembling this furniture is prohibited min haTorah even though it is made in a way that an unskilled person can assemble it. Thus, the definition of “skill and strength” is not whether the assembler needs to be skilled or strong, but whether the appliance thereby made is a permanent, well-made appliance.
Focusing a pair of binoculars involves turning a screw to make it tighter and looser. Does this violate boneh on Shabbos?
The poskim rule that one may focus binoculars on Shabbos (Kaf Hachayim 313:73; Ketzos Hashulchan 119:12). They explain that there is a qualitative difference between screwing the base onto the cup, which creates an appliance, and screwing the binoculars, which is the method of using it. One may use an appliance, just as one may use a house by opening and closing the doors and windows. This is not considered building an extension onto the house, but normal daily usage.
Many shtenders are tightened and loosened by the use of a screw. May one adjust ashtender by loosening and tightening the screw?
According to Rav Shlomo Zalman Auerbach and Rav Vozner, one may adjust the height of the shtender on Shabbos since this is considered using the shtender, not making a new appliance (Shulchan Shlomoh 313:7; Shu”t Shevet Halevi 6:32; cf. Shu”t Minchas Yitzchok 9:38, who prohibits).
I forgot to fill the saltshaker before Shabbos, and now I realize that it is empty. May I unscrew the saltshaker on Shabbos to fill it, or is this considered demolishing and repairing the saltshaker?
Rav Shlomo Zalman Auerbach rules that it is permitted to open, refill, and close the saltshaker on Shabbos without violating boneh. Although the saltshaker is indeed screwed closed, it is typically not screwed as tightly as one screws furniture or the cup we described earlier (Minchas Shlomoh 1:11:4 s.v. gam nireh).
A similar halacha, although for a different reason, applies to opening and closing a baby bottle. Although it is opened and closed by screwing, since it is intended to be opened and closed constantly, it is not considered demolishing and reconstructing it.
If someone’s eyeglass lens falls out on Shabbos, may he reinsert it back into the glasses?
It would seem that it depends on the type of eyeglasses. In glasses where the lens is held in place simply by placing the lens in the frame, one may pop the lens back into place. This is because placing the lens into the glasses cannot constitute boneh since it does not require skill.
However, there are some frames that tighten around the lens with screws. According to the Magen Avraham, it would seem that tightening the screws to hold in the lens involves a Torah prohibition of boneh. If that is true, then one may also not pop the lens because of concern that one might screw the frame tight.
We may ask ourselves, why is screwing a cup together or removing a window from its hinge considered melacha? They take a second to do and are not at all strenuous.
Rav Samson Raphael Hirsch (Shemos 20:10) notes that people mistakenly think that work is prohibited on Shabbos so that it should be a day of rest. He points out that the Torah did not prohibit doing avodah, which connotes hard work, but melacha, which implies purpose and accomplishment. Shabbos is a day that we refrain from constructing and altering the world for our own purposes. The goal of Shabbos is to allow Hashem’s rule to be the focus of creation by withdrawing from our own creative acts (Shemos 20:11). By restraining from building for one day a week, we demonstrate Who indeed is the Builder of the world and all it contains.