AC Delco hand held tachometer 1940-1950

[walz]

What I have is a hand held tachometer that my father in law had used forever, until he died of old age. It's been sitting for ten years before I was able to use it.



Anyone who has one of these little gizmos, I need some help, when I place it on the engine belt, it maxed out the RPM's. I've tried it on several vehicles and I get the same result.

I know this can be fixed, however I need someone who has one to give me an answer I really don't want to experiment with a really old tool that will work if I can get educated on it.

(btw: these photos represent my tool, I sourced them off the internet.)

And thanks for your site, it's a great place to learn about stuff, this place helped me restore two old tools and I'm using them all the time.

 

[91bronc300]

I think that that contact tip might be worn. The way you are trying to use it would be if you were trying to measure surface feet per minute which I don't think that tool is setup to measure (but it might be). I think it's supposed to have a tip with a cone that you can put into the center of a rotating shaft.

 

[mitusa]

I think that that contact tip might be worn. The way you are trying to use it would be if you were trying to measure surface feet per minute which I don't think that tool is setup to measure (but it might be). I think it's supposed to have a tip with a cone that you can put into the center of a rotating shaft.

This ^^^^^^

 

[walz]

I thought you place the tip on the belt of a running engine, like the alternator, and it gives you the rpm.

I'm lost on what it does..........

 

[Advan]

Here's a video on using a little starret. Disregard the babbling, and forward the video to about 9:00.

<iframe width="560" height="315" src="//www.youtube.com/embed/4RLnwgp6YcM" frameborder="0" allowfullscreen></iframe>

 

[walz]

Now that make sense, I'm now on track, so I put it on the end of the pulley not on the belt. OK cool I'm going to try that and I am glad someone helped me on this learning curve. Again thank you.

 

[walz]

I Just checked this out and it works great.



This is a great tool, I'm glad it works even if it's 60+ years old.



They sure don't make them like this anymore. Everything is made in China, and it don't last long.

 

[walz]

Thanks for your resources again.

 

[Packard V8]

I've never seen the Delco, but Stewart-Warner still makes one which works the same principle.

jack vines

 

[DekeT]

I think you are supposed to put it in the center of the rotation. Try using it on the end of a crankshaft. Putting it on a belt will not tell you anything.

 

[ttpete]

I have several that are a bit more sophisticated. They're mostly used in machine shop work to check spindle speeds, and they also have attachments to directly read surface speed in feet per minute.

 

[walz]

I think you are supposed to put it in the center of the rotation. Try using it on the end of a crankshaft. Putting it on a belt will not tell you anything.

That's what I said my problem was, I was not using it correctly, without someone to show me how to use it I was lost.

 

[MikeF2316]

My uncle had one of these. He sold radiators for huge stationary engines, they used this to make sure the electric fan motors were up to speed.

 

[walz]

My uncle had one of these. He sold radiators for huge stationary engines, they used this to make sure the electric fan motors were up to speed.

It's a really great tool, I'm still sifting through my father in laws tools, finding things like this that are a real treasure. This tool has lasted one generation for 60+ years and now I am using it. How cool is that.