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Sheldon 10" X 24" 1936 Sheldon Need to kow what the 6 speeds are ? Help

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  • Sheldon 10" X 24" 1936 Sheldon Need to kow what the 6 speeds are ? Help

    I have a Sheldon 1936 Model with 6 speeds and need to know what they are. It has a 3 speed flat beld drive and a 2 speed for a total of 6 speeds. The quick change gear box does not state the 6 speeds, only the feed rates for screw cutting.
    on the Way = LWQ7862P
    model = FLWQ
    bed lenght = 44"
    This is a 10" X 24" and I was told it was an 1936 Army Lathe, any HELP would be appreciated very much. Thanks

  • #2
    Well you can look at the motor plate and find its RPM, then measure the pulleys diameters, and a little division and you'll find the speeds.


    • #3
      That's because the QC gearbox has nothing to do with the speed at which the spindle (and thus the chuck) rotate. It controls the ratio between the spindle speed and the leadscrew speed. This ratio (which remains the same for a given setting of the QC regardless of the spindle speed) is used for cutting threads. The carriage of the lathe can engage the threads of the leadscrew (via the halfnuts). Since the leadscrew is turning this will cause the carriage to move toward or away from the chuck, depending on which way the leadscrew is turning. The rate at which the carriage moves for each revolution of the spindle is what the QC controls.

      Most machining books will go into thread cutting into much more detail if you need it. South Bend's 'How to Run a Lathe' is one good source.

      Hope this helps.