As the number of new slot car enthusiasts we deal with increases we hear from some who are not familiar with gear pullers and presses. These simple but effective tools are a must for any racer who wants to change the pinion gears on his motors. Gear changes, of course, are an essential part of tuning cars for optimum performance on any particular track and power supply. Pullers and presses are designed to exert steady, even force to install or remove gears without damaging them or bending motor shafts.
Gear pullers consist of a framework with thin jaws that slide in on either side of the motor shaft between the pinion gear and the can or endbell. Most of the pullers used in slot car racing are circular in shape, similar to the one shown in Fig.1. A screw with a thin shaft on the end pushes on the end of the motor shaft and as the screw is tightened it drives the motor shaft back through the pinion gear until it has been driven all the way through and the gear is removed, as in Fig. 2.
Every gear press, regardless of what it looks like, is essentially a clamp, exerting controlled pressure on gear and shaft to press the gear into place. You can actually use some ordinary C-clamps as a gear press, as well as a bench vise or an arbor press. You can also use a drill press by simply chucking in a piece of bar stock to give you something to press with.
To press on a gear, place the motor and gear into the gear press as shown in fig. 3. Then, begin turning the screw, applying even pressure. The screw will press the end of the motor shaft through the gear and beyond, if needed for the particular gear installation, as shown in Fig.4.
Some manufacturers make a single tool that combines the functions of both puller and press. These have the advantage of compactness and allow you to carry one tool in your race case instead of two, but these combination tools are not always as durable as the separate ones and may not accommodate as large a range of motor sizes. It’s also worth noting that virtually all motors presently used in 1:32 and 1:24 scale slot car racing at all levels have .078″ shafts (the exception is the FF motors, which have a smaller-diameter shaft), so once you acquire a good puller and press they will serve you no matter what kind of racing you get into.
Copyright © 1997, 2009 Robert M. Ward.¬† Used by permission.
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