Inside A Cheapass Tachometer
Added 2021-05-08 19:50:04 +0000 UTCCan a cheap contact tachometer be any good? Let's find out!
Comments
Hi Fran, it's me again, I have just been watching a Russian guy spin a tyre ( sorry Tire) up to stupid speed and record it on a UNI-T UT372 tachometer. AND Guess what, they are as cheap as chips and non contact!!! : https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=UNI-T+uT372+tachometer&_sacat=0 Here is the video to watch it: https://www.youtube.com/watch?v=Evkk1WwnpXg I have some of their gear and it is excellent quality. Hope this may help you, (you can always ebay your crappy one so as to offset the cost) Best wishes as always. Mike
Mike Hughes
2021-05-17 17:00:51 +0000 UTCI need a contact because the rotation rates I want to measure for clocks and geared motors is quite slow.
Fran Blanche
2021-05-14 17:34:21 +0000 UTCYou could fill that top plastic piece that holds the shaft with epoxy, drill out the hole after it cures, then cram two good bearings in it. Lipstick on a pig for sure, but at least it'd be mechanically sound.
Michael Eagan
2021-05-14 06:29:32 +0000 UTCLaser Optical Taco - no muss, no fuss, no men left on base. Yes a fine-tip white paint marker is a useful addition in the carry case. But you leave all the other grief.
Mike O'Dell
2021-05-10 02:28:25 +0000 UTCOh that thing is utter rubbish. Should use AA rather than AAA (at least it didn’t use button cells!) The shaft should have two bearings, or a main bearing and a sintered bronze bush near the rotary encoder to avoid vibration noise and inaccuracies. The rubber parts falling out is laughably bad, what cheap trash. I’d be returning it on that issue alone. I suspect is does have a ball bearing, but a very cheap n nasty thin one hence the incredible sloppy play. As for the photogate, wow, just wow.
Anton
2021-05-09 09:48:18 +0000 UTCHi Fran, cheers from Pisa
MVVblog
2021-05-09 03:23:10 +0000 UTCSomewhere... Someplace.... Someone was giving a PowerPoint presentation on the design of this thing and a room full of engineers said, "Oh, yeah! That's great!" Another room of mechanical designers also thought "Oh, wonderful!" And some Program Manager said "There's no way we can't make money on this!". Then whoever distributed this said "Ah, it's cheap. Our customers won't know the difference. No one would actually open it up to see this abomination of tolerances." Then you bought it and exposed just how low all of them can go. You could have built a better one with a used rotary encoder and Audrino board!
Matt Wietlispach
2021-05-09 00:27:57 +0000 UTCWell you could use it as a cheap ass-tachometer, assuming your ass has fairly regular rotation
Norm Nelson
2021-05-08 20:56:37 +0000 UTCThank you for not hyphenating "cheapass". https://xkcd.com/37/
lohphat
2021-05-08 20:54:38 +0000 UTCI got rid of my contact tach decades ago, mainly because I didn't like getting that close to rotating equipment with power applied. Got a non-contact laser tach and never looked back. I get very accurate readings a meter away from a 3 cm shaft. I keep some emery cloth handy to dress dirty shafts, and some white nail polish when I need to add a reference line, though a piece of tape almost always does just fine. With careful aiming it even works great end-on.
BobC
2021-05-08 20:47:23 +0000 UTC
