FYI,
This is a Model No.5 or No.5-1/2. Those two models differed only in the main handles. The No.5 has a hollow storage handle with a round cap. The No.5-1/2 has a solid handle with a large "mushroom" or "doorknob" shaped pad on the end, making it easier for the user to push on the drill with their chest.
Many Goodell Pratt tools are not marked with the model numbers. This one looks to early to have a number but if it did, it would have been on the ferrule of the main handle. The handle and ferrule on this tool look user-made.
I think this one was made in the 1920s. After about 1915 or so, the spindle thrust is taken by a ball bearing assembly at the front of the spindle bore. In the earlier version, the thrust bearing was at the back of the spindle. There are several features that date it before the Millers Falls/Goodell Pratt merger in 1931. It has the older style tapered crank arm and the more slender, tapered crank knob. The spindle thrust bearing has 3 rings not 2. The later thrust bearing have only the 2 steel races, and omit the brass ball cage.
