Digital Tachometer, Mengshen 2 in 1 Non-Contact & Contact Speed Meter Rotation Tester TH-522

Good value for money, and sturdy

This Item is still in use and works as it says on the Instructions,

My use for this tachometer is to measure the speed in RPM of a small shaft rotating in the range of 2.5k to 10k RPM. I suspect that due to the small shaft diameter use of the optical pickup seemed unsuccessful while use of the direct contact method provided consistent results. The tachometer is easy to use once it is mastered, in that it needs to be aligned with the rotating shaft correctly and allowed adequate time to provide a correct reading.

I deliberately chose a more costly product hoping for good quality but was disappointed. Did not work out of the box, freezing and/or displaying random readings when pointed at still objects.Unable to achieve a stable and/or sensible reading from a rotating engine that I have been working on. Avoid.

Good value, easy to use. I cant speak with much authority re accuracy, however I do have a 1400rpm motor I tried and it measured the speed at 1425 so its definitly measuring with some degree of accuracy.

Optically works great if it's an engine that can be stopped to sticker the pulley. Howevere the mechanical drive wheel can be very difficult, mine actually through off the rubber drive piece and it disappeared.

I used this to calibrate a CNC router for cutter speed. It's easy to use with different rotation heads, It's also easy to read with it's large LCD screen. I would certainly recommend this tachometer.

when used as non contact it gets a ridiculously high reading of anything that rotates regardless of it being reflective or not or whether the reflective tape is used, on a plus ish side the contact wheel works but you need to work out the ratio of the rotating part and the wheel to work out the true rpm, I would have expected some way of inputting the diameter (in my case lathe chuck) to automatically give the correct rpm