BOLTR: Musical Reeds to measure RPM
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- čas přidán 24. 06. 2019
- This old tachometer uses music box type reeds to measure motor RPM without electricity. It's more useful than a digital Tach because it shows you resonant frequencies and can be used to check hammer and reciprocal speeds too. Thanks for helping me make more movies, I appreciate your help. Early access here: / ave
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Forrest Addy, who besides being an amazing keeper of machinist lore is also an opera singer, told me a story about a giant machine whose purpose I can't remember, but had started shaking around the shop floor. It had a dozen internal places where something could have gone wrong, all of which would be a week of heavy work to dismantle the machine to inspect.
Forrest had the brainwave to bring in his tuning forks. By holding each of them up against the machine he discovered that the machine made the A fork sing. 440 hz. He figured that 440 had to be a harmonic of the problem vibration - they looked through the drawings and found a 110 tooth gear. Opened the machine up and found the gear with two teeth broken.
that's the problem, it should have been 432hz
@@mikowai 432 is a very unpleasant tuning in my opinion, you can’t go down more than one octave easily.
Resonant frequencies, I can set my fiddle on top of my piano and hit an A note on the piano and watch the A string vibrate on the violin.
Try to put the piano on a skill saw and see what key vibrates
EagleKeeper makes sense, that’s a pretty neat trick though
cool
@Bob Bobbertson They're literally the same instrument so I'm not sure what you mean.
@Bob Bobbertson yeah it is lol its a southern american name for it
I used one of those back in the 80s at a Cadillac dealership to diagnose Driveline vibrations
Was just gonna ask if it would work for ICE.
I used on in the 90's for the same thing. Sometimes worked better than the new EVA "Electra vibration analizer"
briggs and stratton 19200
@@transdimensionalist my boss at the A-1 Air Cooled small engine shop had one that had a long wirery lead off of it. Cool beans.
@@pegtooth2006 That's a Sirometer.
"Myrtle if you're out there, I hope you're enjoying your retirement." 😂
I saw we find myrtle
I just picked one up at a boot sale - "inspected by 55" - so Myrtle's best friend then?
Had an old generator with one of these to show the line frequency. After it warmed up, you would fine tune the throttle until you got 60hz.
f = (N*P)/120
They automatically tune reeds with laser in harmonica manufacturing nowadays, so wouldn't be too expensive once the tooling is made. Still probably more expensive than slapping together a bunch of SMD components on a PCB.
You and your harmonica manufacturing!
@@ShainAndrews Big Harmonica strikes again
Lasers are used to 'tune' SMD components like resistors also. Just a fun fact. 😁
Harmonicas are good .
Correct, could definitely be automated
Drooling over that, now off to fabricate one with three rows and tritium paint
Tritium ❤
They still make them! Sticht 9281 Compact Vibrating Reed Tachometer 2500 to 6500 RPM for a cool $323.60 USD.
'Batteries not included'
Crap I was just looking on amazon hoping to have one delivered tomorrow for $29 😢
Yep I use these very often to measure natural frequencies of the machines I design for my job. Not even lying here, I design vibratory equipment. We normally use reed tachs in the 400 to 1200 and 1200 to 2500
I come from former USSR and remember seeing very similar instrument long long time ago. It had the same springy metal flaps, but it was used, and I may be wrong, to show the frequency of the power supply network.
Correct, vibrating reed frequency meters work on the same principle. They have an electric exciter coil in the case to energise the reeds which are spring steel.
@@rayg9069 Yeah, I figured that it would have some sort of mass that is pushed around by the alternating magnetic field.
They are cool bits of kit.
I love how the Frahm logo shows how the instrument works (shows vibrating reeds with the A vibrating the most).
Mine goes from 4000 - 8000 RPM in two rows.
The top row indicates 4000 - 6000 and the bottom row indicates 6000 - 8000.
So cool.
I custom tune and re-build harmonicas, so I can appreciate the hand work that goes into those extended reeds.
R. Akers did you buy a house in hgtv 😂😂😂😂 (Jab jab)
@@sharksshark6212 lmfao
Then you sir are a wizard. I play harps and regard them as black magic , instruments of the devil.
@@tinman7781 google Richard Sleigh / hotrod harmonica and Brendan Power
I found them by accident when I inhereted 50 old harps, and got hooked on the hobby.
Sane players just use the tricks to do maintenance, since all of the custom tunings are now available at Sydel
Next time you knock the dust off the missus, keep it close by to count the hammer blows per minute.
Let us know how it works.
It would never work. The sampling period is too short.
😅😅😅👍👍 Brilliant
@@BLenz-114 😅😅
Absolutely brilliant! Thanks for bringing finds like these forward AvE!
Fuckin cool instrument, the simplicity is damn near beautiful.
One of a very few youtube channels where the comments are worthy of the video presentation, which is singularly stellar. Keep 'em comin', guys.
Due to being a responsible adult I havent had much time to be on the AvE tube lately. Got a lazy rainy Sunday and this is one of the coolest damn things I've ever seen. Besides how it works, someone invented this! I will definitely be keeping my eyes peeled at the swap meets for one of these.
Such a simple tool it almost hertz that I didn’t come up with it myself!
I can harmonize with you, it happens to me with much frequency.
@@arduinoversusevil2025 I just thought I'd _Note_ that the _Scale_ of your comment struck a _Chord._ I'm going over the _Bridge_ and right to the _Bar_ to work-off a _Fifth_ for _Scale._
@@arduinoversusevil2025 It's a real nice item Fourier toolbox.
AC come, AC go
AVE, love the videos, always a bright spot in my day. Thanks man.
I'm an old guy and I can remember using this type of tacho to measure steam turbine speed, (small Parsons impulse wheel) as well as for adjusting small diesel generators while bringing them online. The new digital instruments are more accurate but not as much fun. I love you channel Cheers
Wow, I knew I've seen one of those before! I'm from PA and my father used to do the photography for Biddle Instruments in their catalogs. They were a client of his for many years and I have been out at their facility a few times to help him on location shoots for some of their bigger products. My father used to have a lot of their smaller things in his studio for up close shoots with proper lighting. I sort of remember handling one of those but I didn't really understand its purpose at the time. Thanks for the flashback.
Quality content as always! This would be a great teaching aid to have in a science classroom.
I just received my 3 t'sharts for Fathersday. Thanks AvE. That is one cool tool.
Holy crap, I just used a larger version of this just yesterday to diagnose and calibrate an electronic pickup tachometer for a dyno. The electronic one was jumping around and giving all sorts of false readings trying to get it dialed in. I pulled my harmonic tachometer out of the cabinet, held it against the frame and had a perfect reading. The one I've got at the shop has about 4 times the span and the same resolution. Absolutely incredible!
I too have a deep appreciation for analog measurement devices. Wonderful video. Resonant frequencies!
Awesome! We used to have these on our old aircraft power generators, I never knew how they worked. So cool.
I saw this device on Reddit and have been waiting for AvE to review it.
I have used a device like this to measure natural frequency on vibrating quarry equipment. Good job and an excellent way to learn about resonant frequency
Our power supply for the Hercules aircraft use those! Glad you showed us the inside. Cool tech, always wondered. Thanks!
Awesome job these meters, found a couple in a box in the back of the workshop today. I love the old stuff. However i used a different take on this resonant frequency meter (called a cirometer if my memories correct) that was a single springy wire in a spool that could be extended or retracted and once the the wire went crazy like the reeds here in these tools we knew we had the correct point. It had a little window with the corresponding numbers to tell you what the frequency was. Used it on compaction rollers to ensure correct compaction for asphalt etc.
Just brilliant. People forget how innovative people were and pretend that anybody born before the transistor was a moron. Folks 100, 200, 1000 and 2000 years ago were just as clever as us; they just a more limited tool kit. They were still able to find novel solution. People forget how innovating they can be if they don't have access to the latest gadgets too.
An illuminating little artifact here full of tidy reminders. Thanks for introducing me to this.
I love "old school" tools and devices. That thing is skoocum as frig!!!
Found this in my inherited tool box this morning.
How cool.
Thanks for the info.
These are still available, maybe not as tachometers, but they are used as frequency indicators on AC switchboards.
Cole-Parmer still sells them as tachometers. They're a bit pricy at about $500 a pop, though, with an additional $140 for NIST Calibration. (edit) I take that back. A quick search tells me that reasonable digital vibration tachometers go for around $400 to $800, so $640 for an analog tach that will essentially never die is well worth the money.
It's basically the same thing, except it has an electromagnet underneath them.
@@ke6gwf different range of frequencies, though - the ac frequency meters are set up to measure only a bit above and below 50Hz (or 60 if you are in an area with a 60Hz system)
Early radio control systems used this principal. When a solenoid vibrated the Reed bank the one that resonated completed an electrical circuit....
All this talk about vibrating and not a single inuendo..everything okay AVE?
I have one of these for sale. It has two rows of teeth. What is is worth I'm 65 and don't work anymore.
@@paulpulliam2913 -- It's worth what you can get for it. Total junk to some people, a hidden treasure to others.
@@TlalocTemporal I'd love to sell mine I'm not going to be changing any boat propellers any more. It really shines for that. I have zero experience selling anything on Ebay,, but My rural doesn't have too any chief engineers.
Super cool old school! Used them on some of our old steam turbines. They really well worked well!
It's a Reed tachometer, and we actually still use them for a secondary tach when doing turbine overspeed trip tests at my refinery.
I watched this a few hours ago but didn’t have time. to comment.
This is why I watch your channel.
I love this s**t. Old analog gauges, giant spinning governors steam engines, old HD electrical relays, etc.
This one was really cool. So simple and genius.
Definitely EMP proof.
It's like a Fourier Transform for mechanical vibration. I like it.
My thoughts: "Wait.... are those prongs tuned to resonant frequency?!?!?!" ("Tines", I learned a new English word.) I've never seen one of those, thanks for showing, I love simple mechanical/analogue stuff like that!!
If you've ever used a fork, you've been eating off tines! Lol
Robert Lee I would’ve called them prongs, before. Tines are thin, (often) tapered prongs, right?
FloppyHares apparently they are nearly interchangeable but tines can be blunt or sharp. Forks and combs, however, have tines rather than prongs.
@@tsloth1390 Ah, OK, thanks for the explanation!
This tries together so many concepts from my Instrumentation class this past semester.
I used to have to catalog those things. They were tuned by musicians and came in a few ranges. We used them to check RPM for aircraft turbines and airframe vibrations. The P-3 Orion's had them in their special gear list. Getting them calibrated was a PITA, but the cal was good for like 5 years.
We still use these in the oil refining business. We check the rotation speed of our large steam turbines with them. Great vijao AvE!
I love this old stuff. I work in steel mills that date back to the late 1800's and find all kinds of old stuff like this.
Gotta love the beautifully simple yet complex engineering
Not going to lie I totally tool nerd it out on this one too when I seen you put it up to the lathe, I knew immediately how it worked
60$ last month - 400$ now. Thanks AvE!
Fantastic videos you make. 👌🏼👌🏼
And love the way you talk! 😜👏🏼
I wonder if the twisted pieces are to stop interference from standing waves inside the sealed casing ?
I love this old reed tacho, my auto NVH teacher taught us about this fantastic tool.
I've learned something interesting today. Thanks man
I gotta set me one of these up on the old bed post and see what she shakes at. :P thanks for another good one uncle B
My dad worked in the power generation industry. I remember as a kid when I would visit the plant they had these with like 3x the range. They were in a fitted leather case. They would use them on top of the old turbines during run up to keep an eye on things. Forgot all about them till I saw this video. Neat.
Good job, you just quadrupled the cost of these little blighters since the video .... greetings from Australia
I might try making one of these!! AvE I’d love to see a video of you doing this as well!
That's absolutely beautiful in its simplicity.
I'm not much of an enginerd (jazz-hands routine is more in my wheelhouse) but I'll still pick one of these up someday if I've some spare cash.
We still used these while I was co-oping at a water pump company during undergrad last year. Great for checking motor rpm on a well pump or sewage pump that's underwater. Just put it right on the discharge pipe.
I love 20 minutes from Plymouth Meeting PA. So cool!
Wow, from Plymouth Meeting, PA! That's where my company is located! Sittin' here right now watching CZcamss for work!
this was skookem as hell, thanks for sharing. Never imagined such existed.
My brother works for Megger! :) Old school Science and Tech is fascinating, and we would not have the modern stuff without it!
That's the coolest thing I've seen in a long time, why would they move away from this kind of stuff frickin outstanding
Always did love those. I worked on USAF generators that had them. Generators had to do 3-phase AC, 120 AND 240 volt, 396-404 Hz as read on the vibrating-reed gauge, from no load to full 7200KW and back to no load. 4-71 Detroit diesels with no turbo. If you were good, like me, you had them at 2 Hz fluctuation load/no load/load. Those reed gauges are range-limited but damned accurate and important for that level of tuning.
That's the coolest thing I've seen in a long time.
Never before seen the inside of one of those, thanks AVE.
we still use these once in a while for our fleet of locomotives. Every once in a while our digital tachometer gives us weird readings, so we double check it with one of these. We have a set of 3 of them with a very wide range of readings. Old school but reliable
These are also common on older generators as the output frequency meter, except they have a magnet coil inside to excite the reeds with the output frequency. Was always fun tuning the old mil surplus governers!
we have these on our aircraft ground generators i always thought they were electronic. you learn something new everyday.
This sort of thing was also used back in the late '90s and early 2000s for Formula One commentary, back when TV didn't have direct access to telemetry from the cars, so they used an acoustic tach to work out how hard the engines were revving. Turns out to have been pretty accurate, showing some cars topping out at about 21,000 rpm.
Back in the day, we used a few reeds like this to decode tones in a remote control receiver in say an Airplane. All that was required was to send the output to the coil that was connected to the reads instead of the speaker. Then the tone hit the resonance frequency of the reed, it went crazy and hit the mating contact and hence activate that servo. It works well and allowed cheap radio control of a few channels.
Was going to comment the same thing but you beat me to it. Oh well, I suppose this channel does attract the most smarterest commenters...
Wow. Im truly impressed by this device
I have a sirometer at work that works on a similar principal. I use it for NVH issues on cars. Resonance frequency and a bit of math usually pinpoints the suspect area.
Very cool.
DAYUM!!! I feel so old now... I used to use those at work in the Pump Stations in New Orleans to measure harmonics in the pump housings.
they also used to make an identical looking unit to measure AC frequency. there are still some in use today, the only moving parts were the reeds and the instruments were made with such quality they last several lifetimes,
I know this is an absolute shot in the dark, but I teach 7th grade science. There is a large portion of the year where we talk about waves and this would be an amazing tool to show my kids that waves are everywhere! We could examine objects in the room to determine their wave patterns and even just to illustrate that waves can exist even when they can't be seen! If you know somewhere that someone on a teacher's salary could pick one of these up it would be greatly appreciated!
These are definitely still manufactured and in use. I use one ever y day at work to monitor the output frequency of a diesel generator.
A quick google of "vibrating reed tachometer" will net you a few manufacturers.
Very similar to the tone generation on a Wurlitzer electric piano. It's tuned by adding or filing off solder.
Thanks for the movies!
We used reed tachs at the GM dealership back in the 80's. It sure was simple. Now we have electronic one's that give so much info your head spins. KISS.
Too bad my Chevy dealership doesn't know how to use one.. (typical Siverado Z71 vibrator..)
There is no fix for those. @@scooterbum46
The joke he made about the Megger that it gives electrical apprentice a shocks yeah that really does happen. Couldn’t help but chuckle a little. Love your vids @ave
You find the best gizmos man 😊.
beautiful simplicity, elegant design. I imagine something like this but larger could be used to extract energy from noisy and vibratory things.
Wow, what a beauty! A treat especial indeed!
Got one of them in my little Honda EM600 generator, used for tuning the throttle to 60/50 Hz for the AC output. Thought that was so cool when I first saw that (and still do).
Neato, glad I tuned in!
As many have already pointed out you can still buy them new. McMaster Carr sells this case style as well as the smaller "pen style" VIBRA TAK which have a sliding wire reed. You adjust the length of the reed until it starts vibrating like crazy and then read the rpms or vpms. Called Pocket Vibration Monitors on the McMaster Carr website. Others vendors sell both styles, and VIBRA TAK sells direct from the company. Made in the good old us of A.
I had a guitar tuner in the 70s that worked on the same principle. Sympathetic vibration.
This is brilliant... Simply brilliant
Some of our power carts for aircraft still have these. They show 350-450hz. 400hz systems
Have seen one old for AC HZ so simple and brilliant.
Thanks for showing that. I always wondered how those worked. I have an old electrical meter that indicates phase order for 3 please and there is a meter that looks like that, that tells the frequency of the AC. I have used it to set the rpm on generators and it more stable than my Fluke meter and just as accurate.
We still use these in the shop - quite common. They aren't cheap but you can buy them from Cole-Parmer Instrument Company LLC. `Vibrating Reed Tachometers`
This was surprisingly interesting!
Very cool!
Thanks for the video.
What, no peak hold? haha Early tv remotes had a lil set of 'chimes' that would ring at different freqs to decode into different commands. But you prolly knew that. Love your channel sir.
That's why even today some people call a TV remote the "Clicker".
The tie rod thing is used to set the maximum travel for the dingus ends, that's why it has some black cushy material on it.
And the plates are twisted so the wedge themselves into the slots in the case, just a little bit so the font rattle.
Another type of ingenious and simple measurement device is the Eriez vibration displacement sticker. It is a paper sticker with a steep V printed on it . It is applied to the side of a vibratory feeder. When the feeder is vibrating the lines of the V will appear to cross at a point on the V which is equal to the vibration displacement. It is used to adjust the feeder to correct operation.
I just found an old light intensity meter in a drawer that gave me some good vibes. Must have one of the original prototype photovoltaics in it because it's just the tiny PV cell and an analog ammeter clamped in one of those classic light gray enameled steel cases with the rounded corners that I associate with 50s - 60s gadgets. Someone had dropped it and the needle's spindle has fallen off it's little cup screw, and it has to have set like that for a couple of decades. Fortunately, the era being what it was, the thing was held together by screws and a minor amount of dickering got it working like a charm, if not a lil uncalibrated.
great knowledge. it would be cool if aircraft or long running automotive companies revealed how they deal with keeping things out or even helping a ground loop.
That is indeed brilliantly simple!
Cool stuff. Might be interesting to play around with a speaker and a frequency sweep.