1. Remove left-hand cover.
2. Slide off carrier with all its wheels. Later (plastic case) models require
you to depress a brass spring underneath to allow this.
3. Change the appropriate wheels on the Carrier. This contains:
*A large brass X wheel (118 to 150 teeth) which has
brass or plastic hub pressed into its centre.
*An intermediate brass wheel (55 teeth) - leave this in
place unless very badly worn and loose on its spindle.
*A white or grey nylon bevel gear, on top of:-
*A small brass Z wheel with 2 slots on upper surface.
This comes with 70, 58, 48, 39, 32, 27, 22, 18, or 16
teeth. The smaller ones have no room to stamp the number of teeth on them
so you will have to count them!
4. To re-calibrate you only need to change the X and Z wheels. (See illustration
below). Slide the old ones off, push out the hub from the large X wheel.
With the new wheels in place, the meshing will be incorrect, so turn the
carrier over and slightly loosen the two screws A and B. Screw A enables
the intermediate wheel to be moved into the mesh with the X wheel, do this
adjustment first; the other screw - B, enables the small Z wheel to be adjusted
in relation to the intermediate wheel. Adjust so that the wheels spin freely,
tighten the screws and check they spin again. Replace the bevel gear, engaging
it with the two slots in the Z wheel. On later models a spring is fitted
which engages in slots in the X wheel hub and the bevel gear, thus preventing
them from falling off when removed. This should only have enough tension
to perform this function and be fitted correctly, or it can completely cut
through the bevel gear causing loss of drive and class win! Both ends of
the spring should be inside of their respective spindles.
When replacing the carrier unit in the Halda, make sure the protruding
end of the bevel gear shaft engages in the sliding sleeve on the selector
shaft (the +o- control).
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