Screw Cutting Lathe, c.1860
Charles S. Mosely
Waltham, Massachusetts
The three bearing slide spindle Nashua lathe was developed by Charles S. Mosely. This early form of screw cutting lathe, although still manual, allowed the operator to perform several processes successively on a piece of steel rod in order to produce one screw. By pressing the foot pedal under the bench, the operator would open the spring collet and advance the steel rod stock. When the pedal was released, the stock was held in place by the collet and rotated as the line shaft above powered the belt attached to the lathe. As the stock rotated, a cutting tool was manually applied to it by the wooden lever located on the front of the machine. This process determined the fixed diameter of the screw.
The special tail stock (located on the right hand side of the machine) was set to perform three functions. The first spindle served as a "sop" to regulate the length of the screw when the steel rod stock was passed through the collet. After the diameter of the screw was cut, the second spindle used a threading die to cut the thread into the stock. The third spindle was then used to chamfer the screw. After the process was complete, the machined stock was cut off at the collet and placed into a slotting plate. When the plate was full it was taken to a separate screw head slotting machine for completion. The output of this machine was approximately 1,200 to 1,500 screws per day.
Purchased with Museum Acquisition Funds
1997.46.4