ML7 Backgears

A clarification of how the backgears on the ML7 work.


View from the front of the headstock.
Pully (3) is connected to gear (2)
Gear (6) is keyed to the spindle
Screw (1) allows for adjusting the wedge that connects gear (2) to gear(6) (see detail fotos below)

With the wedge connected, driving the pulley(3 + gear 2) drives gear (6) via the wedge, thus providing direct drive for the highest 3 speeds.

With the wedge disconnected the pulley (3) spins freely together with gear (2).
The backgears (4,5) are engaged by the lever at lower right.
Now, driving the pulley (3) causes gear (2) to drive gear (4) which is connected to gear(5).
Gear (5) drives gear (6), thus giving 3 slower speeds for each belt position. (6 to 1 reduction)

If the wedge (1) is left engaged, engaging backgears will cause the spindle to be locked against rotation.
(Do not use this as a means of removing the chuck if it is stuck as the gear teeth are brittle and WILL break)

Last edited February 20 2013 09:52:24.

Right hand detail view of the wedge adjusting bolt in the bull gear. By loosening this bolt, the wedge can be slid up in the slot, thus disconnecting the bull gear from the driving pulley/gear assembly. Now the backgears can be used to connect the pulley assembly to the bull gear with a 6:1 reduction ratio.

Last edited February 20 2013 09:52:26.

Left hand detail view of the wedge. The wedge consists of two teeth that match the teeth of the small gear. The small gear can spin freely within the large gear when the wedge is withdrawn.

Last edited February 20 2013 09:52:26.

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Last modified: February 20 2013 07:52:30.