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Doc's Type I Erector Swinging Saw (First Prize, 1917)

Hi folks, Doc here. For the 1917 Gilbert Prize Contest, young John Russell Botton of Philadelphia, PA submitted this entry, the Swinging Saw (also known as a pendulum saw), for which he was awarded First Prize. In the description at the time, Gilbert wrote "This model requires patience but if nicely built will reward the builder for his efforts, and the design is excellent and works perfectly."

Overall, I found the design to be clean, simple, and quite functional. In particular, the design of the saw swing-arm assembly is quite clever. The motorized pulley which drives the assembly is located on the same axle upon which the assembly pivots. In this manner, the belt between the motor and drive pulley remains taught while the saw assembly is free to swing back and forth across the width of the cutting table.As you can see in the photos, the swing-arm assembly has a large #17 spoked pulley wheel and two P7 small pulley wheels at the top. At the bottom of the assembly another P7 wheel rests against a #18 round plate, which functions as the saw blade. The rear photo of the model shows a string running from a P7 wheel on the motor to one of the P7 wheels at the top of the swing-arm; this drives the large spoked pulley, which by way of a second string running to the P7 at the bottom of the arm drives the saw blade itself. A 21-S slotted strip near the lower end of the swing-arm functions as a "handle" for pulling the saw blade across the stock to be cut. 2 more slotted strips projecting forward from the upper end of the arm have a counter-weight suspended between them. This weight keeps the saw blade hanging behind the table when at rest. When the saw handle is pulled forward, the blade cuts the stock; when it is released, the saw blade swings back behind the table under its own weight.

The model was fun to build, and what a pleasure it was to "fire up" that 80-year old electric motor and watch the saw blade begin to spin, just as John Botton watched it do after he first built his Swinging Saw!