I have been fortunate to handle many hand drills model No. 2.  The 1903 edition is particularly interesting to me for several reasons. 

First, this release incorporated all major design elements that provided for long production run - over 35 years.  Small changes were obviously introduced over time - spring chucks, reinforcement for spindle housing, different shape of side and crank handles, modification in ball thrust bearing, etc.  The core design, however, stayed the same during these 35 years  - one pinion, friction roll, frame design, three-jaw chuck, and hollow handle.

Second, there is a magic in this drill release.  It is the most smooth, balanced, and handsome operator of them all.

Third, I found fair availability of this model on the second-hand market.  This provided me with an opportunity to get deeply familiar with this release and restore several dozens of them to user-friendly condition.

With that in mind, here is an anatomy of the Millers Falls No. 2 Hand Drill - 1903 release. 

The Millers Falls Company - Catalog "B" Pocket Edition, c. 1903:

"Drill No. 2 is same in general finish as No. 1, described above.  It has cut gears and adjustable friction roll to prevent gears from springing out of engagement.  The Chuck holds from 0 to 17/64.

Price , with 8 fluted points...... per dozen, $30.00"

At the time these drills were produced and sold, their appearance and functionality was very similar to the drill seen on the images below.