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30min in… what arent we talk about lol

Haaaa F-ou-rier yes I know this one.

Free comment no association with this dude other than being a happy listener

If you are looking for a genuine buyer for your plates I am very interested in purchasing them

WRT the low sample rate on the roundness tester: you might try software equivalent time sampling. Instead of trying to sample all the points you want in a single revolution, synchronize the sample clock to the encoder's output, with an adjustable phase offset. Say you sample once every revolution, that's not enough to measure anything! But if you take that same sample at very slightly different offsets each time the spindle goes around, you can get the effect of having one sample from each offset. You can get far more points than your encoder's number of steps, since you can have a precise & fast clock as your reference source. This does have some issues: if the error motion changes (say, from heating) during the sampling some of the points will be before the change & some after. Also if your integration time for a sample is too high (slow ADC might take significant time to settle, not sample over a short enough instant) it'll average out the value over that time.

Which ADC did you use for your testing? Thank you, this series has been exceptional thus far.

how much would it cost me if l order 2 of them ?

Blowing our minds! Thanks for the great education. Reach out to @Dan Gelbart. He mentioned in one of his videos that he is using electronic equipment for super precision mechanical measurements. Maybe you can cooperate.

Looking forward to the return of your air spindle and the applications of this series as well. thanks again... off to watch the fourier video.

Hey Cyclo, I am a mechanical engineer student fresh in the program. I was wondering if I can apply to a machine shop without any hands on experience. I am willing to learn and build things. I love your work and want to do what you do!

I am sure that I will come back to this series many times over the years. Thanks for going to the effort to do a good job oa this.

8:50 ish: is it because the axis of the measuring device does not always intersect the line through the center of the ball parallel to the axis of rotation?

you can also compute just the frequency bin corresponding to 1UPR and subtract off the sine wave of the resulting phase and amplitude; rather than doing the full DFT and IDFT. it's easy enough to use a library for the full DFT, but working with a single bin will build understanding of what the fourier transform is actually doing: a coordinate transform into a new basis via a bunch of dot products, one per component

If you remove the first one term from the Fourier, the run-out is gone but if there is a syncronous component too!? Or there is no component in the first term!?

Do you prefer Onshape to Fusion? I noticed that you have both, and I just started using Onshape because I don't want to use Windows anymore.

Really good ! Thanks!

Awesome. ... now I get to beat my frustrations out of me in the gym while listening to machining ASMR😊 We use LVDTS on our massive steam control valves upstream om our main steam turbines. And our condenser bypass steam valves. Because steam flow has such a direct an big impact on Reactor power be need to have high control feedback on these valve positions.

The question at 8:17, I'm not the best as describing things, but I am fascinated by these sorts of precision videos. My guess as to at least why its not a pure sine wave is because measuring it from a fixed point, it may be in line with the center of the sphere twice per revolution, but that means it will be measuring the artifact offset from the center twice as well. Your peaks and valleys of the sine wave would be correct for a pure sine wave but the middle portion would be off more the more runout your artifact has.

Can you just add an out of phase sine wave and adjust its amplitude to mi imize the RMS error over one rotation?

Thank you very much for sharing all your knowledge! I hope you can get those busy guys (Adam and Josh) to make more microcast podcasts! Thank you thank you thank you!

Furry signals = fourier transforms ❤ What's the title/source of Bob's thesis you refer to several times? Like the 22:26 "FFT result of the 128 rev. test"

I saw the same mechanism on the gas seals of a dresser rand compressor. They are truly smooth.

I guess the shape of the runout curve is a cicloidal. Which for small run-outs is almost the same.

I'm waiting for the collaboration project with Mr. Renzetti! This is mostly over my head, but well done!

Привет, спасибо за видео, мне очень интересна эта тема😊. Можеш сказать на какую камеру ты снимаеш?

Is there a way to dynamically compensate for these runoff errors, such as using a voice coil attached to a mass, which inputs the exact opposite force to counteract the error on the spindle? Or is this this impractical?

What a fantastic lesson in measuring actual error! Bravo!

I'd imagine the data analysis would be even easier if you can set up two gauges at approximately 90 degrees offset from each other, to treat as combined complex-valued samples -- given that the FFT is a natively complex-valued concept. Though you'd probably need a preprocessing step similar to removing the n=1 eccentricity, where you put the second measurement through a linear transform that minimizes the n=2 frequency component, to cancel out the error in that sensor's relative placement.

Quite nifty as always! I'm very much digging this series. & I strongly agree that Fourier anything(series, analysis, transforms & their inverses, discrete or not etc.) are among the most useful & powerful ideas ever. As they're used in engineering of ALL kinds. I'll never forget how totally blown away I was when some of these things started to really sink in. If only Jojo could see his rather simple ideas being used in our modern world as both conceptual AND actual machinery(especially software/hardware).

Re: it's not pure sinusoidal - thinking out loud here - it must be due to the radius of the artifact, right? A R=0 artifact would have to be perfectly sinusoidal (obviously not realizable). A R=inf artifact would give perfect sinusoidal motion too.. Hmm. I think it's that the indicator has a small size in the insensitive direction, it isn't measuring the tangent of the artifact. As the artifact moves in that insensitive direction we get still a sensitive direction effect from the artifact's curvature. So larger artifacts would have less effect. If the runout == artifact radius R, you'd indicate at 0 and 180 are +2R, -2R as expected, but at 90 degrees you'd measure 0 (just kissing the edge) instead of the closest side being at +R because the artifact has completely moved away from the contact point of the indicator.

Any info on that capacitive gauge sensor? Is it available as standalone sensor with analog output or full measurement system is needed? I am looking for something in mere mortal price range. Not afraid of hardware firmware development but seems lot of theory available on net but no standalone sensor source.

Where can i learn more about how size of interferance fit effects bearing axial clereance, and how to calculate minimum shaft size depending of spindle speed? thanks:D

Highlight of my week, thanks for putting the time and thought into these vids.

In regards of ADC: What about an oscilloscope? Modern, even cheap scopes have resolution of 12bits. With a hilarious degree of oversampling you'll be able to eke out extra 4 bits no problem (just make sure the memory depth is adequate). Given where you are going, my guess is you'll need a scope anyway...

Most certainly need to watch this again when all parts is out

Your demonstration at 3:48 was so good! I'm blown away by the quality of this series that everyone can watch for free on TH-cam! What a time to be alive.

Will the theory described in these videos be applied to making new amazing parts?

A careful descent down the rabbit hole, rather than free fall. A brilliant series that just keeps getting better. Long before the Great Flood, I had to go to graduate school to get the experience of teaching. There's no better test of how well you know your subject than explaining it to someone who is seeing it for the first time. I had good exposure to the power of Fourier transforms, but never in this context. Adam Demuth (@adamthemachinist) is probably the gold standard of teachers on TH-cam. Like the rest of us, you don't have his magnificent voice, but for clarity and the use of creative toys for illustration, you're giving him a good run for the money. Anyone who has seen his videos will know that this is about the highest compliment I can give you.

Awesome series! I'm making a list of all the topics promised "for later" - there is no escape.

Regarding putting an indicator on the shinny surface and it not telling you much about error , please pass that along to used machine tool buyers. That and the five puck test on grinders both seem to get used a lot but machine dealers to sell not great machines to the uninformed

I like the googly eyes on the millimess

I really hope you cap off this series with a video or two showing the implementation of everything on your diamond turning lathe

Fourier FTW!

7:32 So runout refers only to the outside surface of the spindle, whereas for a spindle to have error, the actual axis of rotation needs to un-align itself? I’m thinking of a camshaft which can have horrific “runout” in spots, but it still spins true.

Just an FYI I was able to order a copy of Precision Spindle Metrology from DEStech publications. They said that it had to be reprinted but they sent my copy today.

I'm loving this series! Looking forward to part 3!

It's so true, I've been looking for a video about this for over a year, some good ones, but not exactly what I wanted, them small numbers :D

what did you put on the laser to give a diverging beam?

How is the pil pressure regulated so that they are all the same?

As a crude hobiest, this is way out side what im ever considering. But an amazing explanation for something that's not very intuitive. Nice work.