Mark VII headstock initial breakdown

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Some of the pix in this thread(and later ones as well) will illustrate differences in the Mark VII from a Mark 5/V.

The motor pan was removed first. It will be detailed in a separate thread.

Then the belt cover screws were removed, but a problem arose immediately.

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The headstock lock was 'engaged' and the interference went away.

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A couple of pix were inadvertently left out when this post was created. They can be viewed etc. here http://www.shopsmith.net/forums/showpos ... ostcount=5


Well this is certainly 'different'. It is to disengage the drive gear that engages the gear rack on the way tube to allow positioning the headstock sans crank(just like a 'normal' SS).

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And here it is on the inside. Notice the end of the shaft has a cam. What that does will be explained later in this thread.

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The most noticeable thing here is the larger size of the eccentric(other than those gears - more about them below).

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Belt jam inside also. The eccentric can be moved to release it.

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This is something not on a Mark 5/V. The latch detents into grooves in the rod extending from the carriage. When latched, the carriage and headstock move together. It also eliminates the need for the way tube headstock/carriage spacer. This is located in the right end(quill end).

[attach]18848[/attach] [attach]18849[/attach]
..........disengaged.............................................engaged

There is only one headstock lock and it is located at the opposite end(left) from the Mark 5/V. Subsequent tear down reveals a second wedge between the worm gear and the headstock lateral movement crank.

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The speed control changed very little near the slow range, and wanted to jam near the fast range. The reason is shown here - badly worn belt.

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Now about those gears and the cam on the belt cover. The spur gear(on top) engages the gear rack on the way tube. The bevel gear is manually driven by a crank that also controls the headstock lock.

Notice the pin that is partially pulled down. The pin engages a recess in the spur gear. The cam on the belt cover pushes the plate below the bevel gear as I am doing manually. The cam is located between the lower plate and the bevel gear.

[attach]18852[/attach]

The plate when fully lowered pulls the pin entirely out of the recess in the spur gear thus allowing it to free wheel. The shiney surface in the recess is the shaft, not a pin.

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The eccentric in addition to being larger than that on a Mark 5/V appears to be split on the bottom as well. It may be two pieces as indicated by the difference in the distance extending from the bore(or it may be 'broken'). It is NOT broken. It is ONE piece.

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Well the idler shaft itself looks different. That nut secures the idler shaft and prevents it moving into the headstock. The 'tab' prevents the nut from loosening.
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And the headstock end after a bath. Notice the 'crank' on the right. When pulled 'down' and rotated the bevel gear turns. When the red knob is 'flipped up'(as shown), the headstock lock is engaged. The wedge is to the left and presses against the rear way tube.

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Inside after a bath.

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Outside after a bath. Methinks the 'cleaner' used resembles grandma's lye soap since it loosened(dissolved) some of the paint.

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Inside motor pan(no bath yet!). A difference here is that ALL wiring is contained within the motor pan sub assembly.

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Outside motor pan. One of the mysteries is why it says Mark '7' here and Mark VII elsewhere. The three 'buttons' control forward, reverse and stop. The stop must be pressed prior to changing directions and the key switch must be be set to enable either direction. The key switch is actually a mechanical interlock. Rotating the key counter clockwise allows the forward switch(on the left) to be depressed. Rotating the key clockwise allows the reverse switch(on the right) to be depressed. When the key is in the center position(and removable as shown) neither forward or reverse switches can be depressed. Thus to change directions, the stop button must be pushed, the key repositioned and the other direction button pushed.

[ATTACH]18862[/ATTACH]

One last 'difference' is that there are two screws in the quill end of the motor pan. The vacuum housing is in the center.



This thread is linked to from https://forum.shopsmith.com/viewtopic.php?t=11373

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The motor belt could not be removed from the motor pulley due to close spacing to the pan.

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'Solution' was to loosen the pan to motor screws which allowed raising the motor away from the pan.

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