Shopsmith won't turn off

[Keithbirch]

I have a shopsmith that stays running unless the power is disconnected. There is a safety key in it that looks like it is not in all the way but it should not start with it out. Any ideas would be appreciated

[jsburger]

The only thing that interrupts the power to the motor is the switch. Seems like you need a new switch. Something is wrong with the switch mechanism if the safety key will not go in all the way.

[mountainbreeze]

I've had 2 switches fail in the on position (very dangerous!) - the original keyed one that came with the Shopsmith and the first (3rd party) replacement. If I flipped the switch on and off several times, it would finally turn off. Guessing it was fine sawdust getting into the small openings in the switch body, I used hot glue to seal those openings in my second replacement. So far, so good.

[Ed in Tampa]

I think it is more likely that a high voltage draw welded the switch contacts. But only a dissection of a faulty switch would tell the answer.

[chapmanruss]

The Red Safety Key Switch is used in all "C" Headstocks. That is any headstock from 1991 on. There have been two different Red Key Safety Switches used since the "C" Headstock introduction that I know of and the keys are different. Outwardly the switches look very similar but the keys are very different. The problem may be a damaged key which is more likely in the early switch, damage to the switch itself or something in the way of the key fully going in. Remember if the switch is in the on position the key would have to be reinserted with the receiving part in the on position. The picture below is the two different keys used in these switches. The one on the left is the newer style key and the one on the right is the older style key.

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Red Safety Key Switch - keys.jpg (51.71 KiB) Viewed 652 times

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Below are the complete switches with the first being the newer style and the second being the older style.

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Red Safety Key Switch - new.jpg (48.14 KiB) Viewed 652 times

Red Safety Key Switch - old.jpg (52.82 KiB) Viewed 652 times

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If there is no damage to the key for your switch, try to SEE if anything is in the way inside of the switch that is keeping the key from going all the way in. If nothing is seen blocking the key it is likely a problem that will require replacing the switch. The switch is part number 556089 Headstock Locking Rocker Switch and is currently on sale for $25.93.