Accurate; reasonably priced optical tach

[Quickstep192]

Has anyone found a reasonably priced accurate optical tach?

I know quality and inexpensive don’t usually cross paths, but I’m asking anyway.

I need to accurately measure idle rpm on a mechanically injected diesel engine.

An optical tach seems like the way to go.

I had the Harbor Freight model a while back and it worked well right up until it didn’t work at all.

Surely there are options between the HF cheapie and the $300 aeronautical models.

 

[pembol]

Some of the various tachometer apps for iOS/Android work quite well up to a couple thousand RPM. If it is a dark enough area, the strobe lights ones may be a little more accurate than the frame rate ones.

 

[BillK]

There are quite a few available for model aircraft use. Do a search on RC Model Aircraft Tachometer

Google Search

 

[jayemm]

Amazon has quite a few at various prices. I have this Uni T UT373. Has a backlight and counting feature. For my limited use I wouldn't spend any more. One thing I did learn (not tach specific) regarding the supplied reflective tape was that beyond the "peel-off" to expose the adhesive, the other side had a (hard to notice - almost clear) "peel off" which if not removed didn't properly reflect the light beam and caused erratic RPM readings. There's youtube videos on digital tach's that might prove instructive.

UNI-T UT373 Mini Digital Tachometer, 10~99999 RPM Non-Contact Tachometer Speed Meter Speed Gauge with Backlight, Max/Min/Data Hold, Rotating Speed/Count Function Switching: Amazon.com: Industrial & Scientific

UNI-T UT373 Mini Digital Tachometer, 10~99999 RPM Non-Contact Tachometer Speed Meter Speed Gauge with Backlight, Max/Min/Data Hold, Rotating Speed/Count Function Switching: Amazon.com: Industrial & Scientific

www.amazon.com

 

[rlitman]

The last super Chinease $13 laser tach I bought has been working perfectly for me over the past decade. Don't overthink this. My cheapie works better if you pre-install a strip of the reflective tape, but I've been able to get speeds of fans with a plain white card behind them, by dividing by the number of blades.

 

[Quickstep192]

Thanks. The plethora of options on Amazon was what brought me here to get advice. Unfortunately, I didn’t see any on Amazon that got really glowing reviews.

Good intel on the tape.

 

[jayemm]

Thanks. The plethora of options on Amazon was what brought me here to get advice. Unfortunately, I didn’t see any on Amazon that got really glowing reviews.

Good intel on the tape.

As said above, don't overthink this. Try a ~$15 cheapie and see if it works for you. Can always get a better one. This video helped make my decision to buy it.

 

[Quickstep192]

Well, I hope you guys get a laugh out of this…

I was searching around for an optical tach with decent reviews.

I saw the Neiko 20713A and went searching for places that sell it.

Naturally, Amazon popped up and when I went to view the item, Amazon told me that I bought one 4 years ago. I found it on the shelf where I store my lathe accessories. I recall that I used it to calibrate the Variable Frequency Drive on my lathe. I evidently put it away and didn’t need one until today.

It even works. It also appears that I had the presence of mind to remove the battery after the last use.

Now, if I could just find the tool I misplaced last week!!

 

[rlitman]

Well, I hope you guys get a laugh out of this…

...Amazon told me that I bought one 4 years ago. I found it on the shelf where I store...

Now, if I could just find the tool I misplaced last week!!

ROFLMAO, this is MY story too!