יורה דעה רע״בYoreh De'ah 272

Se’if 1א׳

אֵין עוֹשִׂין סֵפֶר תּוֹרָה לֹא אָרְכּוֹ יָתֵר עַל הֶקֵּפוֹ, וְלֹא הֶקֵּפוֹ יָתֵר עַל אָרְכּוֹ. פֵּרוּשׁ, יְכַוֵּן שֶׁיְּהֵא חוּט הַמַּקִּיף יְרִיעוֹת כָּל הַסֵּפֶר לְאַחַר שֶׁיִּתְפֹּר וְיִגְלֹל, אָרֹךְ כְּשִׁעוּר אָרְכּוֹ (טוּר). וְכַמָּה הוּא אָרְכּוֹ, בַּגְּוִיל, שִׁשָּׁה טְפָחִים שֶׁהֵם כ"ד אֶצְבָּעוֹת בְּרֹחַב אֲגֻדַּל שֶׁל יָד. וּבַקְּלָף, אוֹ פָּחוֹת אוֹ יוֹתֵר, וְהוּא שֶׁיְּהֵא אָרְכּוֹ כְּהֶקֵּפוֹ. וְכֵן אִם עָשָׂה בַּגְּוִיל (פָּחוֹת מִ) שִּׁשָּׁה טְפָחִים, וּמִעֵט הַכְּתָב, אוֹ יִתֵּר עַל שִׁשָּׁה וְהִרְחִיב בַּכְּתָב, עַד שֶׁיִּהְיֶה אָרְכּוֹ כְּהֶקֵּפוֹ, הֲרֵי זֶה כְּמִצְוָה. וְהָעַמּוּד שֶׁבְּתוֹךְ הַסֵּפֶר, יֵשׁ אוֹמְרִים דְּמִצְרַף לַהֶקֵּף (טוּר בְּשֵׁם הָרֹא"שׁ).

One does not make a Torah scroll with its length greater than its circumference, nor its circumference greater than its length — that is, he should see to it that the thread that goes round the sheets of the whole scroll, after he sews and rolls it, is as long as the measure of its length (Tur). And how much is its length? On gevil (hide prepared whole), six handbreadths, which are twenty-four fingerbreadths by the breadth of the thumb of the hand. And on klaf (parchment), either less or more, provided that its length is as its circumference. And likewise if he made it on gevil less than six handbreadths and made the writing small, or more than six and made the writing broad, so that its length is as its circumference, behold, this is as the mitzvah. And the rod that is within the scroll — there are those who say that it joins in the circumference (Tur in the name of the Rosh).

Se’if 2ב׳

אֹרֶךְ כָּל שִׁיטָה שְׁלֹשִׁים אוֹתִיּוֹת, כְּדֵי לִכְתֹּב לְמִשְׁפְּחוֹתֵיכֶם ג' פְּעָמִים. וְלֹא תִּהְיֶה קְצָרָה מִזֶּה, כְּדֵי שֶׁלֹּא יְהֵא הַדַּף נִרְאֶה כְּאִגֶּרֶת. וְלֹא אֲרֻכָּה יוֹתֵר עַל זֶה, כְּדֵי שֶׁלֹּא יִהְיוּ עֵינָיו מְשׁוֹטְטוֹת בַּכְּתָב (ל' רַמְבַּ"ם פ"ז מֵהִלְכוֹת סֵפֶר תּוֹרָה ד"ד).

The length of every line is thirty letters, enough to write lemishpechoteichem (for your families) three times. And it is not to be shorter than this, so that the column does not look like a letter; nor longer than this, so that his eyes do not wander in the writing (the language of the Rambam, chapter 7 of the Laws of a Torah Scroll, law 4).

Se’if 3ג׳

אֵין עוֹשִׂין יְרִיעָה פָּחוֹת מִג' דַּפִּין, וְלֹא יוֹתֵר עַל ח'. נִזְדַּמְּנָה לוֹ יְרִיעָה בַּת ט' דַּפִּין, לֹא יְחַלְּקֶנָּה בְּעִנְיָן שֶׁהָיוּ ג' דַּפִּין בְּאַחַת וְשִׁשָּׁה בַּשְּׁנִיָּה, אֶלָּא שֶׁיִּהְיוּ ד' בְּאַחַת וַחֲמִשָּׁה בַּשְּׁנִיָּה. בַּמֶּה דְּבָרִים אֲמוּרִים, בְּכָל הַיְרִיעוֹת שֶׁבַּסֵפֶר, חוּץ מִבָּאַחֲרוֹנָה. אֲבָל בְּסוֹף הַסֵפֶר, אֲפִלּוּ פָּסוּק אֶחָד עוֹשִׂין אוֹתוֹ דַּף לְבַדּוֹ וְתוֹפְרִים אוֹתוֹ עִם שְׁאָר יְרִיעוֹת.

One does not make a sheet of fewer than three columns nor of more than eight. If a sheet of nine columns came to his hand, he should not divide it so that there are three columns in the one and six in the second, but so that there are four in the one and five in the second. In what case are these words said? In all the sheets that are in the scroll, except the last. But at the end of the scroll, even for one verse they make it a column by itself, and sew it together with the other sheets.