S-W tachometer

Mike(NEOhio) · Feb 10, 2015

I picked up a 82682 hand-held tach recently. Like new but the pointer settles about 50 RPM off the zero. Anybody know how to zero it? The case is riveted and I don't see how the dial face can rotate.

Butch(OH) · Feb 10, 2015

What caused the zero be off is a LOT of use in one direction or overspeeding it. They generally do not come part without being destroyed in the process. It is a safe bet that it reads 50 PPM fast one way and 50 RPM slow the other. Learn to add or subtract accordingly or they can be corrected by overspeeding in the direction it reads slow. Best rig would be variable speed, maybe a dremel tool? If you run it too fast it will be ruined (ask me how I know) so take it easy if you try correcting it.

Mike M · Feb 10, 2015

You speak of ruining one. Well I did too. Checking the RPM of a Kohler engine tach started wiggling and next thing I know it got launched by the flywheel fins ! Did not fair very well upon the landing. LOL

Mike(NEOhio) · Feb 10, 2015

Thanks, Butch. It's in the original box and looks like it's hardly been used. That doesn't rule out "abused", though. I figure for $25 I'd get my use out of it. I was going to do what you suggested, just add or subtract the 50. But I like to keep thing working the way they're supposed to. I'll continue looking for info and try to check it against a known source.

Leroy · Feb 10, 2015

For the known source I would just use a 1725 RPM electric motor with a double shaft, that would give you an acurate speed to check to and give you both directions for checking at the known same source speed. I do not know if a 3450RPM motor would be over speeding it or that could be used as well.

Hobo,NC · Feb 10, 2015

(quoted from post at 18:56:47 02/10/15) I picked up a 82682 hand-held tach recently. Like new but the pointer settles about 50 RPM off the zero. Anybody know how to zero it? The case is riveted and I don't see how the dial face can rotate.

Years ago Stewart Warner gauges had a life time warranty... In the mid to late 80's I sent a tack back to them for repair (used in my boat). They lost it somehow so when I talked to them about it I told them my Speed-o was also messing up they said don't send it back I received a new tack and speed-o no charge...

It may be worth looking into...

IH2444 · Feb 12, 2015

You can get the little digital optical tachs for about $10 on the net. Work great and no contact required. Much safer than contact tachs.

S-W tachometer

Mike(NEOhio)

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Butch(OH)

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Mike M

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Mike(NEOhio)

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Leroy

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Hobo,NC

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IH2444

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