Re: MARK 2 Headstock Parts.
Posted: Mon Oct 11, 2021 2:10 pm
I'll address some of the pictures and questions from JPG's 3rd post above. Marc has provided a nice drawing of the headstock which is a good reference. In the 1st picture in JPG's 3rd post he shows the post with jam nut, knob and the collar from the drive sleeve. The threaded post goes into the center of the pulley end of the headstock with the jam nut end. The knob holds the plastic belt cover on against the flange.
The 4th and 5th pictures are the motor mount with the curved and split part that goes on the grooved collar that is not shown in JPG's pictures 2 and 3 of the Belt Tension Adjustment Crank. The motor is indeed attached only by two bolts to the motor mount. The motor mount is attached by a rod to the motor cover casting that bolts to the headstock. This can be seen in the picture below.
_ .
You can see the rod sticking out the casting in the upper left corner of the picture and the motor mount pivots on that rod allowing the motor to move up and down to tension the belt.
In the picture below you are looking inside the bottom of the headstock. The drive sleeve is at the top with the shaft for the SPT hub above the headstock casting. The Belt tensioning assembly is across the center of the inside of the headstock in which you can see the missing part from JPG's pictures above which is that grooved collar the motor mount curved and split part goes on either side of to move the motor up and down. The collar is threaded and moves back and forth. It has a groove on each side and is shown with one groove facing the camera.
_ .
Sorry for the still dirty parts but this Mark 2 is still in the process of being cleaned up and is not the first one I plan on restoring although other than the headstock it has been disassembled. The other Mark 2 is still mostly assembled. For these pictures I have been taking some of the items apart.
The 4th and 5th pictures are the motor mount with the curved and split part that goes on the grooved collar that is not shown in JPG's pictures 2 and 3 of the Belt Tension Adjustment Crank. The motor is indeed attached only by two bolts to the motor mount. The motor mount is attached by a rod to the motor cover casting that bolts to the headstock. This can be seen in the picture below.
_ .
You can see the rod sticking out the casting in the upper left corner of the picture and the motor mount pivots on that rod allowing the motor to move up and down to tension the belt.
In the picture below you are looking inside the bottom of the headstock. The drive sleeve is at the top with the shaft for the SPT hub above the headstock casting. The Belt tensioning assembly is across the center of the inside of the headstock in which you can see the missing part from JPG's pictures above which is that grooved collar the motor mount curved and split part goes on either side of to move the motor up and down. The collar is threaded and moves back and forth. It has a groove on each side and is shown with one groove facing the camera.
_ .
Sorry for the still dirty parts but this Mark 2 is still in the process of being cleaned up and is not the first one I plan on restoring although other than the headstock it has been disassembled. The other Mark 2 is still mostly assembled. For these pictures I have been taking some of the items apart.