I have an older Black & Decker Sawcat #987. It does not appear to have any way of locking the spindle that I can find.
How are you supposed to tighten down the blade bolt if you can't hold the spindle from turning? It gets semi-tight and then the spindle just turns. The blade is still free to rotate at this point. I don't think there is enough friction to run the motor to snug it up that way.
I am aware of methods to loosen the bolt without a lock (hold the blade with block of wood, sharply applied torque, etc.) but these don't seem to apply when tightening.
(I feel like I may be missing something obvious because this seems like a ridiculous problem!)