Millers Falls
No.3 eggbeater
drill, owned by Randy Roeder, who made this picture and gave me
permission to use it here. The earliest No.3 type. Call it Type 1A, for the smooth idler that was added by Millers Falls to support the side thrust of the main gear. Oddly, this was done before the advent of longer twisted drill bits that necessitated lengthening the main handle.
This is the second of these of which I am aware. It has the no-springs, two-jaw chuck marked with the August, 1877, patent date. The idler of this drill looks somewhat worn. It must have given quite a bumpy ride. Millers Falls quickly replaced this design with the Type 1B, whose toothed roller uses the properties of involute gearing to smoothen the operation, eliminating the cost of the separate machining setup needed for making the smooth idler here instead of just making twice as many toothed pinions as for the Type 1B. This type has the distinct frictional disadvantage that the smooth idler is "encouraged" to turn at twice the rotation speed of the pinion, because it runs on the main shaft that is turning in the opposite direction.