MAKING PRECISION GAGE BALLS

I show making high precision gage balls from ultra micrograin carbide with normal machine shop tools. Includes rough grinding, lapping, polishing and measuring to very high levels. Hertzian contact deformations are discussed including calculations. ** 0.000005" = 0.127µm (not nm) **
#practitioner_of_the_mechanical_arts
Paypal donation www.paypal.com/cgi-bin/webscr...
Support through Patreon / robrenz

[@ThisOldTony]

amazing work as always but fact that you broke out the point contact calcs blew my mind. I clicked the thumbs up button twice!

[@ROBRENZ]

Thanks Tony, glad you enjoyed it! ATB, Robin

[@inifin8]

So you unliked it

[@DHClapp]

@@inifin8 I believe that was the joke.

[@twotone3070]

I love you work so much, I do that with all of your videos.

[@Jeff-yy5fe]

what time was that? Not a TOT joke, serious question.....

[@Redmech80]

I’m a heavy equipment mechanic that does some machine work on the side, and I enjoy trying to work to tighter tolerances than necessary. Some of the farmers and equipment owners I make some parts for think I’m working to ridiculous tolerances when i talk “plus or minus a thou”, I’m not gonna let them see this video, then they will know I’m just a hack.

[@seephor]

A thou compared to what's being shown in this video is like a mile vs. inch.

[@UncleKennysPlace]

I grind mirrors and lenses as a hobby (amateur telescope maker). We use optical testing, and measure accuracy to a fraction of a wavelength of a certain frequency of light. 1/4 wave is acceptable, 1/10 wave gives you bragging rights. A 0.001" deviation across a 10" mirror would render it useless for anything other than applying clown makeup.

[@TheOneAndOnlySame]

I'm a metal worker , and I make pieces where 1 mm more or less is a-ok !

[@cholesterol6703]

@@UncleKennysPlace I think you have just explained the raccoon-look trend in women's eye liner application. They must be using deviated mirrors.

[@MegaRiffraff]

And I thought I was doing good at my measly 1 thousand ☹️ , I had a friend who got me into machine shop , he worked at a hydraulic firm that made pumps for cat , and John Deere back in the 1990s , he said one of their sets worked under 25 / 1 millions of an inch .

[@Goodwithwood69]

I'm only a carpenter, but thanks to you, i wipe my level before i use it! Every time!

[@Molb0rg]

good boy))) sorry :p, can hold myself, but yeah, why not, lol, a good practice.

[@metalbob3335]

Carpentry is hitting a moving target. I tried doing a bench with no nails in a period of a very humid summer and stopped Midway through. after I came back to it in winter all the documented measurements were off. I, out of frustration I ended up using up the wood for jacking up my truck for a brake job. I am a Savage, I know.

[@ypaulbrown]

@@metalbob3335 good one....

[@frigzy3748]

"think about everything as if it was made of rubber" - I was taught that during a scraping class with Mr.King

[@TexasHunter59]

As a machinist for the last 51 years, and finally being able to machine components to +.0000/-.0001 in a production environment, I was beginning to feel pretty good about myself. Now I see this and feel like a hack!!! Thanks Robin.... I'll be sure to mention your name in therapy!!! LOL

[@markrosenthal890]

When I was a kid I would watch my grandfather hand lap the glass for the 8" telescope he made. He would assess the quality of his work using home made testing equipment. He was shooting for 25 millionths or less as I recall. He would have loved to have the testing equipment you show in your videos. Great job with the video and some of us do enjoy geeking out.

[@ramanshah7627]

Same - this process also reminded me a lot of grinding and figuring telescope optics! How cool to get to watch your grandpa do this when you were growing up :)

[@bjornSE]

In an intellectual way I was aware of that everything deforms but your paper towel demonstration completely blew my mind! You measurably deformed a hunk of steel with a paper towel, that's actual magic!

[@StefanGotteswinter]

Super impressive result with moderate equipment, love it! Thanks for sharing, Stefan

[@ROBRENZ]

Thanks Stefan and thanks for watching. ATB, Robin

[@reiniertl]

Hi Stephan, you know from personal experience that "super impressive results" come from mastery and very moderate equipment. You scraping series is mind boggling for someone like me. However, I think Robin went over the moon with this one. A lot to learn from both of you.

[@johnsteuben6864]

That's an excellent explanation of Hertzian contacts! I think your emphasis on the uncertainties in material properties is also spot on - this is often completely glossed over.

[@trackie1957]

One of the most impressive moments of this was something that you probably didn’t think much about - the little array of grooves you made in the lap using the dental burr. Beautifully spaced, great workmanship for a 60 second job done by hand. You obviously take pride in doing things well.

[@ROBRENZ]

Glad you enjoyed it!

[@NotFarmerFlats]

It seems to be a machinist thing to be especially proud of their chamfers, always pointing them out. I love it. It is always a nice touch, attention-to-detail kind of a thing.

[@YCM30cnc]

NOT BORING !!! EDGE OF THE SEAT INFOTAINMENT 👍👍😎😎💪💪..... glad I got your autograph when I met you at SMW Open House ⭐️⭐️⭐️⭐️⭐️

[@oxtoolco]

What's the modulus of kimwipe material? Fantastic video Robin! I always find it fascinating that with very simple tools you can produce wonderful geometry just by following the rules of physics. Well done my friend. All the best, Tom

[@yawpaw9796]

You two are very usefull humans, write a book, my sons will know about people like you

[@terryhillyer529]

Tom already did.

[@paumasip]

@@yawpaw9796 i think he did, at least, 2 times. :-)

[@ROBRENZ]

Thanks Tom, means a lot coming from you! ATB, Robin

[@Mishn0]

I don't know about modulus, but I know Kimwipes make terrible coffee filters. We found that out in the middle of the Indian Ocean back in 1979. I don't think Amazon would have shipped out there even if they existed.

[@Engineerd3d]

Mind blown, if precision measuring was a class, this video is a full semesters full of learning packed into less than 1 hour. Good lord. Loved every second of it. Edit: it probably is a class.

[@davidhughes8539]

Thank you Robin for the time, energy, and thought I'm sure it takes to put out videos of this high quality. Thank you for sharing your knowledge and experience. I'm thinking we could crowd fund you a film crew so you could do a video each week! Keep them coming!

[@ROBRENZ]

Glad you enjoyed it!

[@Rob_65]

Well spoken. Making stuff like these balls is difficult enough without having to film it. Making quality videos like this is an amazing trade that only few master.

[@zephyrold2478]

I second that.

[@bigmotter001]

@@zephyrold2478 I third it!

[@beachinrc101]

4th

[@malachilandis9542]

When Robin has an apprentice, they must first master the art of "Kimwipe on, Kimwipe off, Kimwipe on, Kimwipe off" before they can learn the truly powerful techniques.

[@creamshop]

He has a Masters in Kimwipe engineering !

[@st3althyone]

Robin, you are a great teacher going through all the steps and skipping nothing. I want to thank you for spending all your invaluable time doing this for us that know nothing or are eager to learn something new. We are standing on the shoulders of giants like you, there are not many channels on KZbin that you can actually learn a new trade or improve on what you’ve learned so far. Thank you from the bottom of my heart for taking time off your busy schedule to do these videos, you are the best at what you do, bar none! Edit: Falling asleep through one of your videos is impossible Rob, they’re extremely exciting to watch.

[@shrikedecil]

As impressed as I was over the making of the ball in the first place... ... I'm boggled by the ruby tip!

[@HanstheTraffer]

Rubies are cool ...They have been using them in precision for a LONG time...i.e. bearings in watches, anvils in watches yada yada.

[@TechGorilla1987]

@31:31 - you proceed to give us a master class in precision beyond the normal abilities, set up a measuring stand that's like a space ship and then proceeds to humble himself by saying "rudimentary measurements"! Sir, you are a straight up artist. We had the pleasure of talking for a moment a few years ago when you were in Ohio. It was an honor. I wish you had the ability to make more content.

[@saschaoswald480]

Didn't fall asleep....got a "congratulations" from THE Robin Renzetti !!!! Gonna go have a T-shirt made now and call my mother;-) Made my day.

[@sparkyy0007]

Takes a lot of skill to find such a precise gage ball buried in a cylinder of carbide..

[@Molb0rg]

nice one))

[@tsviper]

As always a wonderfull educational video. As a civil engineer I'm happy when you get +/- 1cm. This level of accuracy is way beyond my world. But o so interesting to watch. Thanks for sharing

[@ROBRENZ]

Thank you very much!

[@azenginerd9498]

Having been immersed in developing strain-based sensors a lifetime ago, your nerdfests dredge long-dormant memories to the surface. A very pleasing and cathartic remembering. Thanks for delving into the details.

[@diegovianavillegas3297]

Robin video: A perfect gift for the weekend.

[@blake6403]

I'm 17yr tool & die maker/machinist and am a big fan of your content. Just wanted to say thanks for sharing.

[@andersjjensen]

If you stick around these parts for long enough you end up developing some kind of OCD that tells you that things aren't precise unless you place individual atoms exactly where they belong in their crystal lattice! :P

[@jerseyjoe2684]

With 45 years experience as a machinist/tool maker, I am always humbled watching your brilliant mind at work. Well done, Robin!

[@mftmachining]

same here

[@ROBRENZ]

Thank you very much!

[@nickolaguez]

This is what makes yt powerful. I appreciate you Robin

[@honeyforce996]

This is the best channel. I wish there was a public fund like PBS, which found similar people of this nature, and paid them to demonstrate their technique/experience on youtube.

[@rizdalegend]

"Everything is made of rubber"

[@CatNolara]

Everything is a spring, you just have to look close enough

[@devinpeck101]

We need shirts that say “everything is made of rubber... description in audio”

[@mackk123]

It's all a rubbery playdoh that acts like a diving board

[@JinKee]

Everything is a rubber if you're brave enough.

[@charlesballiet7074]

vibrations technically but close enough

[@AlmostMachining]

Fantastic! From the simple tools and methods to achieve precision results measurable in basically a home shop. Not only to have the ability to perform the work and the measurements but to also back them with science. Thank you so much for pushing the edge and showing the way!

[@georgestone1282]

Puts a new perspective on the world we live in. Very much appreciate the time you have put into documenting this project. George from Indiana

[@christinaedwards5617]

A true master of his craft. Thank you for taking the time to film and explain everything so even I could understand it

[@outsidescrewball]

NO snooze here albeit way above my pay grade...enjoyed!! Many lessons taught..thank you!

[@stevenormandin2059]

WOW we are talking X-ray wavelength precision here, just breathing too close to the measurement test rig will make it go out of tolerances AMAZING! :()

[@lstearns7639]

Thank you for sharing your considerations, methodology, and reference materials. Years from now when facebook, youtube, and instagram are defunct, your lessons will still linger on in our minds.

[@ROBRENZ]

You're very welcome!

[@malcolmreynolds7122]

I had ZERO idea that these sort of calculations went into measuring to those levels. Cool Video! Thanks for the upload.

[@westweld]

When I watch your videos I learn that Im overthinking and underthinking machining at the same time. Its mind blowing that a .0000004 world even exists let alone measured

[@RyJones]

glad you're back!

[@paumasip]

Robin, the amount of knowledge you share on your videos is mesmerizing, love to watch your videos even being far away of my current machining level. thanks for sharing all that in a so crystal clear way.

[@ROBRENZ]

Wow, thank you!

[@thomasutley]

Robin once again demonstrates that everything in the real world is a spring. Fantastic video!

[@divingeveryday]

I would never have predicted seeing a diamond core drill while watching Robin make a gage ball. Wonderful!

[@HanstheTraffer]

One of the many geniuses of Robin...the ability to think outside of the box...a truly great characteristic.

[@Molb0rg]

yeah yeah yeah, that was a good part as well.

[@cliffordfender1159]

I feel like I'm back in college, very well demonstrated, and very well explained. Thanks for a great watch, Cliff

[@ROBRENZ]

Glad it was helpful!

[@corbin72]

Absolutely love these types of videos coming from you Rob. Sometimes we need these detailed videos to wrap our brains around the subject matter.

[@KomodoKiller]

I was not bored in the slightest. Thank you for taking the time to explain extreme accuracy. For me personally it all stems back from when I worked as a centerless grinding technician and measured my parts with a laser micrometers that were accurate to +/- .00000005 (50 Millionth) I felt it was enjoyable to make super accurate parts and nothing was more satisfying then trying to keep the numbers as close to consistent as possible on a long Cylindrical Rod. One moment in particular that stood out was when I was given the “thru feed jobs” that none of the other techs liked to set up or operate. Primarily due to a fear of the wire jumping around while setting up the center-less grinder which would grab at long parts. The bigger the diameter of the wire, ( .150 to .350 for example) the less likely other techs would take the job and set it up. I naturally enjoyed this challenge to the point I “mastered” the thru feed big diameter jobs where the Tolerances we’re in the +/- .05th of an inch 😳. Normally, I was use to keeping tolerances in the +/- .005 range. So, I took it apron myself to bring the accuracy up to my “standards” as a pet project as a way to cure my boredom with a challenge that doesn’t hurt anyone. What transpired over a short time of “R&D” was what I called: Me: “A gag pin for NASA”. On one particular job, I discovered a way to significantly reduce the vibrations of the spinning part while also significantly reducing the ware of the grinding wheel interacting with the part. I ended up finishing the 150ish part job with 10 foot long gag pins that did not Fluctuate in diameter Along its entire length. Which was measured by our in house laser micrometer with a +/- 50 millionths of an inch in accuracy. (Always wanted to test exactly how Symmetrically round these parts were Down to the nanometer. I could never quit understand the “value” of those machined parts and the only close comparison is a 1 inch gag pin with a accuracy of +/- .00005 as the bench mark which go for about $50 a piece.

[@davidmurray700]

AA Guage block standards, but did you account for the difference in gravity between the calibration site and the site of measurement... I had to perform that calculation only once in over 10 yrs in a standards cal lab... You're getting close to those levels of measurement. Thanks for going through the thought exercise, reminded me how much fun it can be.

[@fredgenius]

That occurred to me too. Also, the gravitational influence of all that heavy machinery nearby, and what about magnetic influence?

[@somebodyelse6673]

Is... is that actually a thing, that you have to know geographically where something was calibrated?

[@WesleyLeeYang]

@@somebodyelse6673 I think gravity changes slightly with time (as does magnetic north and so on) so I would guess the location is less relevant than the actual measured gravity on the time/location of calibration

[@douglashill2469]

@@somebodyelse6673 See XKCD 852, "Local g". It would change the weight of the ball by a few percent, potentially.

[@cylosgarage]

Robin is the GOAT and anyone who disagrees can leave

[@tonywilson4713]

How about that French guy Jacques de Vaucanson, he only gave us the modern lathe? kzbin.info/www/bejne/mpulaqKBa9WemKM How about that Swedish guy Carl Edvard Johansson who gave us gauge blocks that allowed modern supply chains to exist? How about Wayne Moore who's work and book “Foundations of Mechanical Accuracy” Robin refers to occasionally. In terms of KZbin Precision machinists yeah Robin's "the dude" and part of what makes him "the dude" is that he's kept these incredible skills alive and shares them with us. What's truly awesome about people like Robin, Stephan G, Tom Lipton and others is that in a world where the geniuses want everything made as cheap as possible and want people like them to simply disappear they are keeping these skills alive. Way back in college when I was doing aerospace I started reading a guy named Asimov. He wrote these "Foundation" novels and in them the Galactic Empire collapses for the simple reason that education collapsed and with it the skill base. I'm in Australia and our industries have been screaming for the last 25 years about the "skill shortage." *What Robin and others are doing that's so incredibly important is they are preserving our skills base.*

[@chenli9734]

Hi, Cylo~! How about your air bearing lathe? I cant wait to see it work.

[@cylosgarage]

@@chenli9734 I’m working on it! More to come soon!

[@pummppkinn]

You are truly in a class of your own in terms of Toolmakers. People like you are what give me hope for future of this industry.

[@jestempies]

I can't claim to have understood everything, but the last 20 minutes were eye opening. Thank you.

[@Alexander_Sannikov]

can you get a pre-made ball bearing and repeatedly measure how it's not perfectly round compared to yours?

[@Molb0rg]

vote that up, I would love to see that

[@misaelv3223]

Same

[@jonfeuerborn5859]

The Carbide Kid say, "Kimwipe on, Kimwipe off. Kimwipe on, Kimwipe off." Well done, Robin-san.

[@user-gy4pm3zi8k]

I've been looking forward to your video for a long time.Some of the details in your video are very inspiring.I learned so much.Thank you very much!

[@yourlocalanimeprotagonist888]

Im keeping it 100 with you i havent touched any of this kind of maching tools in my life but did i watch this entire video yes because i felt the knowladge of a master in this video and its true you sir are most deffintly a master of your craft

[@MrCarnutbill67]

I can’t cut 2 pieces of wood to the same damn length for crying out loud.

[@xMilesxHighxClubx]

lol

[@bloopbloop5663]

Line the first board you cut with the other and cut on the opposite side of the line to make up for the blade width or use a band saw that can fold down to cut like a chop saw I forgot what they were called

[@flintstoneengineering]

"Not a typical home shop"... no kidding!

[@JoeInBendigo]

Oh boy, Robin. That was fascinating to watch - and I was able to follow your entire explanations! I'm still learning lots from your videos. Thank you very much!

[@JeSuisNerd]

Heck I keep going deeper into the precision-machining side of youtube and every day I regret getting into software development just a teeny bit more. I think I'm going to have to take this up as the world's most expensive and coolest hobby.

[@SolidRockMachineShopInc]

As always, another great video Robin! Steve

[@ROBRENZ]

Thanks Steve and thanks for stopping by. ATB, Robin

[@irishwristwatch2487]

"So if you didnt fall asleep through all of that and actually managed to watch it..." Me: What do you mean its the end of the video?

[@beachinrc101]

Love how people who have no clue say dumb things

[@bigmotter001]

Great refresher for us oldies! Thanks for the video and entertainment . Take care!

[@timgrenville-cleave2848]

Hi Robin, not sure how I missed this one the first time around, but, I'm glad I found it. I am a grumpy old git from across the pond, who's early career consisted of causing assorted things and beings to be redistributed over a wide area accompanied by loud noises, and sometimes smoke ). As long as I could work out how far away the object was and how much bang was needed to achieve success and to work out if the Ministry of Defence had indeed issued me with the correct amount of beer tokens each month, I had little use for Math in any form. Turns out I have suffered from Dyscalculia for as long as I can count BUT, I got this straight away and it all makes sense. Now I understand Stefan G's reasons for mentioning your 'lessons'. Thank you.

[@gavendb]

that moment when you can see your face on the ball during the lapping process...

[@aserta]

Rob makes this look easy, but this ain't easy at all. :))

[@capnthepeafarmer]

Hertz contact stresses, now that's something I haven't heard in a long long time. great stuff Robin! I always learn something new!

Thank you uncle Robin. More video please!!!!

[@HanstheTraffer]

Uncle Robin! I like the sound of that. I hope it catches on.

[@ROBRENZ]

Thanks for stopping by Cà Lem ATB, Uncle Robin

[@HanstheTraffer]

@@ROBRENZ I had no idea who uncle Robin was. Also...Ca' lem? Closest I could come is Vietnamese ice cream. ATB: I figure is "all the best". Waaaaay beyond my realm here.

[@AdityaMehendale]

Small correction: 5-millionths of an inch is 127 nm at 27:54 0.127nm is smaller than an atomic diameter of silicon :) Brilliant masterclass nevertheless!

[@citymonkey5929]

Right. Its 0,00012725 mm or 0,12725 µm or 127,25 nm

[@carltauber2939]

Agreed

[@ROBRENZ]

Agreed!

[@BrilliantDesignOnline]

What's a few decimal places between friends...

[@DavidRichfield]

I was also thinking, hang on, visible light wavelengths are on the order of 500 nm, so how can he be measuring fractions of a nm?

[@peterselby5694]

Rob, Fascinating stuff. Always up for more.

[@someoneoutthere7512]

Your precision is a thing of beauty and a joy forever!

[@miguelangelsimonfernandez5498]

Just one minor detail in the presentation of data. Try using lowercase (n) for nanometers because using blockletters can lead to reading Newton-meters

[@paulrayner4514]

I find it difficult machining repeatably to 0.01, in my hobby shed I might add. after watching this my head has gone boom.

[@captcarlos]

WOW Robin, I'm always amazed at what you can do in your 'Simple Home Work Shop'! Plenty of inspiration in this one.. Thank you.

[@trufix72]

Your skills always blows my mind. And I didn't fall asleep.

[@Alexander_Sannikov]

this ball has a ground "equator". it would be really cool to see how you'd go around making it seamless and uniformly round in all dimensions. also, how you'd measure its precision in all axes.

[@HanstheTraffer]

That was the point of the way he set it up AND actually why he used a ball. Just "feel for the top" and you have the highest point in that orientation...leads to ability to measure in all axes. Right?

[@Gottenhimfella]

​@@HanstheTraffer but how would you *identify* an axis, [a prerequisite for controlling orientation], if the equator was no longer a feature?

[@robertstredde6798]

😳 so that final “total approach” number is in the region of an ultraviolet wavelength? Wow! Neat stuff!

[@DCDLaserCNC]

My Dad was a Mechanical Engineer and I remember him talking about measuring things at these extreme accuracies. Very good video and explanations. Thank you for sharing.

[@ianpendlebury3704]

Fascinating and instructive as always. You inhabit a world of precision that I never will, but sincere thanks for sharing the concepts and methodology of working at this level of precision.

[@daviasdf]

Regarding calculating the Hertzian contact stresses, check out HertzWin (freeware). I use it at work all the time, very user friendly.

[@andersjjensen]

I DID NOT read that as "making precision gag balls" at first. I swear.

[@TheArsonsmith4242]

I even had to double check my spelling comprehension. I couldn't read it as anything else. A quick google search and ... ohhh that makes more sense.

[@jaewok5G]

I didn't do it either, so much so that I was going to make a similar comment. "mrph mll lth ngk mblby mlff" "what?" "I was just noticing how perfectly round this ball is" "oh yeah, I subscribed to RobRenz youtube channel and it's brought me a whole new level of precision satisfaction in my life"

[@abkh7777]

Thats the reason i entered the video 😬

[@lordeverybody872]

Rube, i got your gag balls right here.

[@someoneelse7629]

It was my wife who showed me this video, I didn't even know she was intrested in machining, she just started making stuff from leather, so it might be related to that.....

[@heronvontremonia9975]

wow, just got three nice things from this video. first: a useful information (freeing up the diamond with aluminium oxide) second: an inspiration for a project (making diamond laps with electroplating) third: a serious nerdgasm (when i saw your calculations) Thanks!

[@ROBRENZ]

Glad it helped!

[@first_namelast_name4923]

It blew my mind when you demonstrated how to lap that column on your D-bit grinder [deckel clone] some time ago. This video is equally inspiring and perception-changing. Thank you for taking time to shoot AND edit the video for us.

[@davidbingen2377]

When I was doing bridge calculations or even survey calculations, I always tried it keep in mind the difference between accuracy and precision. The two are NOT the same!

[@Jmoneysmoothboy]

If you google "accurate" it says it's the "quality or state of being correct or precise". Which begs the question is google inaccurate? or imprecise?

[@xmachine7003]

@@Jmoneysmoothboy can be both.

[@Jmoneysmoothboy]

@@xmachine7003That answer was accurate but imprecise and this comment thread is "on google". How was the accuracy/precision of google changed? Will it change again with your response?

[@deconteesawyer5758]

@@Jmoneysmoothboy Accuracy and precision of Google results are both adjusted to suit the profitability of ad revenue and the political payoff of censorship in displaying results.

[@alexandrevaliquette1941]

29:00"Yeah, it's accurate, I measured it with my trusty BS meter!!!" "BS" not sure about that logo to inspire trust in precision.

[@Ryan-dz3jo]

Fantastic video Robin, thanks for sharing your techniques.

[@billdlv]

Great job Robin. Your comments about understanding the basics of what is going on is spot on, it's easy sometimes to get lost in the details and loose sight of the big picture.

[@ROBRENZ]

I appreciate that!

[@ZergZfTw]

Nice to see another HP calculator user, that's definitely the best calculator to get actual work done. So, when are you going to get a laser interferometer to measure things?

[@chrisjennings4569]

I think I would not use a laser interferometer. In the above example, utilizing physical metrology tooling gives me confidence in the results. Robrenz accounting of the squish differences gives a solid result with known factors. But the utilization of light brings in something that I have no confidence in. Humidity and density of the surrounding air. I think a lab with a controlled atmosphere and no human contact would give me confident results at this level of precision utilizing light. Just my 2c. :)

[@jmikronis7376]

@@chrisjennings4569, How accurate are interferometers? A state-of-the-art interferometer can measure distances to within 1 nanometer (one billionth of a meter, which is about the width of 10 hydrogen atoms), but like any other kind of measurement, it's subject to errors.Feb 22, 2021

[@chrisjennings4569]

​@@jmikronis7376 As you stated, interferometers are extremely accurate. They use light to take measurements. Water (moisture) will act like a prism and deflect the light causing an error in the reading. Air density will increase or decrease the amount of moisture in a given area and increase or decrease the amount of error in the reading. Even in a controlled environment with air pressure and moisture being controlled, if an object moves in this space, the air/moisture density does change. Like in a bath tub, if one pushes the water to a wall, there is a buildup of fluid at that wall. The same is true with air. So human interaction will cause a change. Even our body temp will make changes. The human aspect is taken into account with the example you brought up. In the case of the accuracy Robrenz is achieving, air and moisture will cause deviations that are difficult to account for if an interferometer is used. The inspection method Robrenz is using will produce accurate, repeatable results in an un-controlled environment. Having said all that, I am curious to see what the deviation is between Robrenz readings and a controlled environment interferometer reading is.

[@jmikronis7376]

@@chrisjennings4569, I included the laser interferometer only because of its extreme accuracy. It’s not a useful device in doing lathe work. Your method is as good as I know to do the job. I think we are in agreement on this. I wasn’t trying to be difficult. My apologies.

[@chrisjennings4569]

@@jmikronis7376 No worries!

[@wdwrxco]

then when you come home and find your kids playing marbles with them...

[@davidcolwill860]

Excellent as always. I don't think I will ever be bored by any of your videos, quite the contrary I often revisit them and get even more out of them. Many thanks. David.

[@ROBRENZ]

Great to hear!

[@swiggle93]

Thank you for the excellent explanation and demonstration of contact pressure!

[@2000freefuel]

Why is it so hard to source a 1 and 1/16" inch tungsten ball?

[@ROBRENZ]

Very low demand ;-)

[@bob5074]

Did you really think we didn’t see in the reflection of that ball, that you were naked when you were lapping it?

[@ROBRENZ]

LOL

[@tomthumb3085]

Thanks for that Rob. Thoroughly enjoyed this insight into accuracy. Great video.

[@donjohnson605]

I love it. I was a precision machinist for many years and find it fascinating 👍

[@jaewok5G]

Now you just need take your number punch and stamp those balls so you'll know what size they are! "You never look at the universe the same once you realize that nothing is remotely solid and 'touching' is an unrealistic metaphor."

[@ahaveland]

Even punching with a number would redistribute the atoms enough that the overall diameter will be distorted and have to be relapped! Just like the diameter of a balloon expands when you press a thumb into it.

[@Gottenhimfella]

@@ahaveland methinks Jim "make ze littel joke, ya?" Good luck punching TC. Would require a solid diamond number punch and preheat to several thousand degrees.

[@69hytek]

Bit rough! Is how I look at my jobs after watching your videos. Tom has the same effect on me as it would happen. You need to make a shirt 'RODRENZ "Lift your game bitch" ' It's an inspirational piece :D

[@KD0CAC]

Always enjoy your works .

[@stumccabe]

Thanks Robin. As usual with your videos, I learned something (several things) new.

[@ROBRENZ]

Glad to hear it!

[@kimber1958]

It kind of reminds me that I don’t know squat there’s a lifetime of learning a head of me

[@xmachine7003]

We are to learn until we die.

[@jeffo881]

WARNING: THE THINKY LEVEL REQUIRED TO WATCH THIS VIDEO MAY CAUSE PERMANENT BRAIN DAMAGE.

[@ahaveland]

Only if you think that the enhanced neural reconfiguration that happens during the augmentation of knowledge in some way damages the previously inferior configuration!

[@jeffo881]

@@ahaveland exactly

[@gwharton68]

Thanks Robin. One of the best YT videos of the century.

[@ROBRENZ]

Glad you think so!

[@907jl]

Great to see a new video Robin, and as usual, you describe a very complex process in an easily understood way. Showing how the minute weight of a Kimwipe actually deflects a test stand by a measurable amount, was simply brilliant! Very well done, and not even remotely boring.

[@ROBRENZ]

Glad you enjoyed it!

[@fredgenius]

The title threw me for a while, thought it said 'cage balls' - thinking, sure I seen this before...