Sometimes, the problem is more serious, with the commutator itself being overly worn and grooved. When replacing it, pay attention to the direction of the curve in the end, putting it back as it was before. Then unscrew a brush and look to see how much length is left-if it’s down to a nub, you need new ones. Check for excessive sparks and arcing, or an electrical “burning” smell. Just look down into the end openings when the motor is running. Those parts, fortunately, are cheap to order and easy to replace. When they get worn down too much, the motors can become balky. That is often due to overly-worn motor brushes. Sometimes, an apparent bad pedal is also due in part to a worn motor. At least that’s my memory.Īt the same time, also pay attention to the motor itself. It’s been a while, but as I recall, there’s a tab at the back edge of the bottom which you bend out of the way, and then slide the bottom off. The foot pedals are not generally made to be frequently dismantled, which is why there are no obvious screws. If it’s that ceramic block with the carbon pile, then if you like you can try rebuilding it. If, inside the thing, you find any electronics components, transistors, resistors, and that sort of circuitry, then toss it. It’s simple enough to open the pedal up and see, since if it’s dead now, you’ve nothing to lose. it’s more costly initially, but they are so much more durable that the increased initial cost will be paid back in greater life span, as well as giving you a better pedal. If that’s the situation, then look closely at the Lucas pedal again. Now, if the control is one of the electronic types, including the feedback types used with series R motors, then the cure amounts to replacing the inner guts of the pedal. All in all, it’s a bit messy, but it does work for a while. Remember that you’re working with full 110 volt current here, so play it safe. In testing the pedal, do be sure to fully reassemble the thing before plugging anything in. If the problem is just that the pedal sticks, then a bit of oil at the appropriate pivot points helps. If it only gives full speed, without the lower speed range, remove a disk to loosen the stack a little. If it doesn’t yet give full speed, repeat. Add a couple, reassemble the control, and try it. If you don’t have an extra pedal to sacrifice, then do the same, but use disks cut from sheet copper. Not as good as new, since the disks are still worn, but it works for a time. If you had multiple bad pedals, you’d then take some disks from one, and add them to another, increasing the thickness of the stack again. Over time, friction and wear and tear and electrical arcing reduce the thickness of some or all of those disks, making it hard to fully compress the stack enough to get full speed again. When you press on the foot pedal, you compress that stack, improving the electrical contact between each disk, and thus the conductivity of the whole stack, and this provides the variable resistance that changes the motor speed. Taking up the distance between them, stacked in the hole, are a whole bunch of disks of graphite. These old pedals consist of a ceramic block with a hole down it, a contact at one end, and a spring loaded contact, attached to the pedal, at the front, the other end. But if you’re forced to try and revive the old one, then here’s the method. If you’ve the budget for one, you won’t regret it. The Lucas control you can buy is so far superior to others as to be seriously worth your attention, but of course, it’s not free. Whether it’s worth doing is another question, perhaps mostly one of budget. Those are a simple design that does not last forever, but unlike the more recent electronic controls also sold, it can be tweaked sometimes to get a bit more life out of them. A: If your old Foredom is one of the old simple CC models, then perhaps the foot pedal is the old cheap “carbon pile” type.
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