Reference for Kelim 29:3

חוּט הַמִּשְׁקֹלֶת, שְׁנֵים עָשָׂר. שֶׁל חָרָשִׁין, שְׁמֹנָה עָשָׂר. שֶׁל בַּנָּיִן, חֲמִשִּׁים אַמָּה. יָתֵר מִכָּאן, אִם רָצָה לְקַיֵּם, טָהוֹר. שֶׁל סַיָּדִין וְשֶׁל צַיָּרִין, כָּל שֶׁהֵן:

The string of a plumb-line [is considered connected up to a length of] twelve [handbreadths]. That of the carpenters’ [plumb-line is considered connected up to a length of up to] eighteen [handbreadths]. That of the builders’ [is considered connected up to a length of] fifty cubits. Exceeding that, if one wanted to retain it [at that length], it is pure [i.e. the excess string beyond that measure is insusceptible to being rendered impure]. Those of plasterers or of [wall] illustrators [are considered connected] at any length.

Jastrow

Jastrow