Place a Sefer Torah next to a Megillas Esther and one physical difference is immediately obvious. A Sefer Torah has two Atzei Chaim, one attached to either end, allowing the scroll to be rolled from both directions. A Megillah, however, will often have only one roller, and many Megillos have no roller at all. If both are sacred scrolls written on parchment, why are they constructed so differently?
The starting point is the Gemara in Bava Basra 14a. The Gemara distinguishes between a Sefer Torah and other sacred scrolls. Other scrolls are rolled back toward their beginning, while a Sefer Torah is rolled toward its middle and has a pole on each side. Rabbi Eliezer ben Rabbi Tzadok adds that this was how the scribes of Yerushalayim made their Sifrei Torah. This is the basic source for the familiar two-roller structure of a Sefer Torah. Bava Basra 14a
The practical difference is easy to understand. A Sefer Torah is used continuously throughout the year, and we regularly need to reach different locations within the scroll. Two rollers allow it to remain rolled from both directions and opened at the appropriate place. Other scrolls were normally rolled back toward their beginning and therefore needed only one roller.
Even this distinction, however, was not necessarily absolute in later practice. The Rashash on Bava Basra 14a notes that although the Gemara describes other sacred scrolls as having one roller, in his city the custom was to make two rollers for Sifrei Nevi’im. His comment is significant because it shows that later communities sometimes adapted the physical form of sacred scrolls beyond the basic arrangement described by the Gemara. Rashash, Bava Basra 14a
Where does Megillas Esther fit into this system? The Shulchan Aruch, Orach Chaim 691:2, rules that a Megillah should have an amud, a roller, at its end, together with enough blank parchment at the beginning to wrap around the scroll. In other words, the basic model of a Megillah is not that of a Sefer Torah with two Atzei Chaim. It follows the model of a scroll that rolls in one direction. Shulchan Aruch, Orach Chaim 691:2
The Rema immediately adds something familiar to many Ashkenazim: the custom developed not to place a roller on the Megillah at all. That explains why many traditional Ashkenazic Megillos consist simply of parchment, without any Atzei Chaim attached. The absence of a roller is therefore not an oversight or modern shortcut. It is a minhag recorded by the Rema.
The Bach on Orach Chaim 691 discusses a disagreement among the Rishonim over where the single roller should be placed. Some placed it at the beginning of the scroll, while Tosafos, the Rosh, Rabbeinu Shimshon and others understood that it belongs at the end. The Bach writes that in his communities the practice was to omit the roller entirely, possibly because of this dispute. Bach, Orach Chaim 691
The Aruch HaShulchan, Orach Chaim 691:7, summarizes the issue clearly. He notes that the Shulchan Aruch requires one roller at the end, while the Rema records the widespread custom of having none. He also suggests that Megillas Esther may be somewhat different from other sacred scrolls because it is read only once a year and is also called an iggeres, a letter. Aruch HaShulchan, Orach Chaim 691:7
There is therefore a surprising range of practice. The Gemara gives us the basic distinction between a Sefer Torah and other scrolls. The Rashash records communities placing two rollers even on Sifrei Nevi’im. The Shulchan Aruch describes a Megillah with one roller, while the Rema records the custom of using none.
What looks like a small question of bookbinding therefore reflects something larger. The physical form of a sacred scroll was shaped not only by halacha, but by how that scroll was actually used and by the traditions that developed around it.
A Sefer Torah is designed to remain accessible throughout its length and therefore opens between two Atzei Chaim. A Megillah developed its own form and its own minhagim. The difference is not merely decorative. The way the scroll is built reflects the way the scroll is read.