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Tach Needle


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I need to be talked away from the cliff!

I have two 4500 tachs. One is a diesel with the yellow/ orange markings and the other is a gas that is all white. I removed the needle from the diesel tach very easily. Positioned a kitchen fork with the tines on either side of the shaft and with the tips centered under the beefy part of the needle. Slight leverage and it came right off.

Did the same on the gas tach and with the same amount of pressure, nothing. Increased pressure to the point where I didn’t feel comfortable any more.

Two questions,

Do I need to apply even more pressure?

Do I risk damaging the movement/ shaft of the tach?

I recently tried to remove the needle from an extra speedometer I had laying around for practice, took a lot of pressure but it finally popped off. Weird thing to me was that the needle came off of a tiny brass ferrule that is still stuck to the speedometer shaft.

Need to hear from those with experience. I have an email into Bob McMullen, aka Rocketman, but no reply yet.

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I’ve taken several tach needles off and never had any trouble. And mine were are from a gas engine.

But the ferrule being left behind is worrying. Does the needle off the diesel have a ferrule? I don’t remember seeing one on mine.

The ferrule I mentioned is on the shaft of the speedometer. The shaft of the diesel tach is a very smooth, slightly tapered steel rod. I’ll send pics in a bit.

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The ferrule I mentioned is on the shaft of the speedometer. The shaft of the diesel tach is a very smooth, slightly tapered steel rod. I’ll send pics in a bit.

Just received this message from the Rocketman

“Those pointers are VERY hard to get off. They are pressed and glued so it takes alot to get them off. The fork method is what I use. You have to be careful because the plastic pointer is actually tacked to the brass shaft assembly so be sure that you are pulling up as close to the shaft as possible.”

And here is that ferrule on the speedometer

IMG_2796.jpeg.726586a78ad84585e1a444f344a834a3.jpeg

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Just received this message from the Rocketman

“Those pointers are VERY hard to get off. They are pressed and glued so it takes alot to get them off. The fork method is what I use. You have to be careful because the plastic pointer is actually tacked to the brass shaft assembly so be sure that you are pulling up as close to the shaft as possible.”

And here is that ferrule on the speedometer

Kurt, would it help if some controlled heat was applied prior to attempting to remove the tach needle?

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Kurt, would it help if some controlled heat was applied prior to attempting to remove the tach needle?

I’ve been thinking the same thing, just trying to figure out how to get the heat concentrated and at a low enough level. That shaft is tiny. Only thing I’ve come up with so far is to use a magnifying glass like we did as kids to burn leaves ( and other things). Can definitely pin point the location and might be able to control the heat that way.

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I’ve been thinking the same thing, just trying to figure out how to get the heat concentrated and at a low enough level. That shaft is tiny. Only thing I’ve come up with so far is to use a magnifying glass like we did as kids to burn leaves ( and other things). Can definitely pin point the location and might be able to control the heat that way.

What about a hand held hair dryer?

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