Make vacuum pre-loaded spherical air bearings without special tools

Ғылым және технология

A new technique to make graphite air bearings without precision tooling. I show how to make spherical, cylindrical, and flat bearings that are also vacuum pre-loaded, meaning the bearing is captive.
David Preiss' excellent video: • DIY Air Bearings
10mm thick graphite sheet: www.amazon.com/Graphite-Smoot...
2" ball bearing: www.amazon.com/Inch-Chrome-St...
Small 10-32 hose barb fitting: www.mcmaster.com/5047k11
Linear bearing shaft: www.mcmaster.com/6061k35
Fusion360 CAD files: drive.google.com/drive/folder...
12x18 granite surface plate: www.amazon.com/gp/product/B01...
Applied Science on Patreon: / appliedscience

Пікірлер: 1 200

  • @MaxJusticz
    @MaxJusticz4 жыл бұрын

    it is hard to overstate how much I want to see you aim a stream of compressed air at the top of the cylinder in the air bearing to get it going really fast

  • @aarongreenfield9038

    @aarongreenfield9038

    4 жыл бұрын

    If he could get the air blowing hard enough you can get the bearing to float on it.

  • @cogoid

    @cogoid

    4 жыл бұрын

    That is precisely what is done in some scientific equipment (used in NMR spectrometry of solid materials)-- a small rotor is spun by air in an air bearings. For very tiny rotors of 0.7 mm in diameter, the speed can be quite high -- in excess of 100000 revolutions *per second*.

  • @texasfossilguy

    @texasfossilguy

    4 жыл бұрын

    Beware the Magnus Effect on that causing lift off of your bearing plate. It needa to be enclosed and magnetically centered also.

  • @pyromen321

    @pyromen321

    4 жыл бұрын

    Tyler Hargrove, interesting thought. I wonder how fast something would have to spin for it to drag in outside air at over 60psi

  • @cogoid

    @cogoid

    4 жыл бұрын

    @@pyromen321 The more immediate -- and a very serious concern is that if you spin anything fast enough, it bursts --and then shrapnel flies literally like bullets. Jesse Wakefield Beams was a scientist who developed very high speed centrifuges. If you look up his papers, he shows examples of sizable steel rotors bursting like artillery shells when spun at some fraction of a million rpm.

  • @AliHSyed
    @AliHSyed4 жыл бұрын

    Love the NileRed beakers

  • @IrishAnonymous01

    @IrishAnonymous01

    4 жыл бұрын

    For those interested: kzread.info/dash/bejne/qGGhua2Ym8bAfdY.html

  • @DeShark88

    @DeShark88

    4 жыл бұрын

    This is why I love KZread! You literally can't get this content anywhere else. Not even Mythbusters is geeky enough for my needs!

  • @Dr_Mauser

    @Dr_Mauser

    4 жыл бұрын

    Giggled when I saw that.

  • @philippelebel008
    @philippelebel0084 жыл бұрын

    "It's like a bouncing ball, but it's an electrical transformer" best quote 2019

  • @Fuogor

    @Fuogor

    4 жыл бұрын

    The last video had a wonderful contender though, "But anyway, back to this ion gun..."

  • @theCodyReeder
    @theCodyReeder4 жыл бұрын

    I want to see this in a vacuum chamber!

  • @besenyeim

    @besenyeim

    4 жыл бұрын

    Me too. I also want to see a collab. ;-)

  • @bluezz5002

    @bluezz5002

    4 жыл бұрын

    Hi cody

  • @guyjacques469

    @guyjacques469

    3 жыл бұрын

    Maybe you make that video n maybe i'll watch it. Eh?☺

  • @tomsplace239

    @tomsplace239

    3 жыл бұрын

    Wouldn’t work

  • @lkjhg561

    @lkjhg561

    3 жыл бұрын

    Wouldn’t work silly XD @Cody’sLab

  • @KowboyUSA
    @KowboyUSA4 жыл бұрын

    That graphite blocks are so evenly porous is quite interesting.

  • @mackk123

    @mackk123

    4 жыл бұрын

    Even carbon filters baffle me. In glad they filter my water

  • @manishiyer23

    @manishiyer23

    3 жыл бұрын

    The grain size of the block defines the cost and quality of the graphite block. Mostly used as electrodes for EDM( Electro discharge machining

  • @simoneden3665

    @simoneden3665

    3 жыл бұрын

    @@manishiyer23 Do you happen to know what grain size is needed for the air bearing in this video? I bought a pice of graphite and it barely has any pores. I read some research on increasing the amount of pores in graphite but there were different techniques for different pore sizes.

  • @creepyloner1979
    @creepyloner19794 жыл бұрын

    keep in mind that if your bearing isn't leveled so that the center of mass is above the center of the bearing, you'll get a bigger gap on the high side and things may start spinning up on their own when they shouldn't.

  • @alastairholland4433

    @alastairholland4433

    4 жыл бұрын

    @Robert Slackware I think they mean that the graphite isn't level and therefore the item in the bearing has more weight to one side of the bearing. This allows slightly more air out of the other side and allows it to spin up. Think about holding the bearing in it's side with the ball in it, the ball will be pulled down by gravity, reducing the air gap on that side and allowing air out of the other which then allows it to spin up.

  • @lazyh-online4839

    @lazyh-online4839

    4 жыл бұрын

    @@alastairholland4433 exactly, new way air bearing did a demonstration using pressure on one of their air bearings as a method of controlling the direction of a thin film-like conveyor held over a set of external cylindrical graphite bearings.

  • @extradimension7356

    @extradimension7356

    4 жыл бұрын

    I was wondering what the expected runout on the centerless ground shaft would be half way down it's length with a dial test indicator and a one sided airbearing.

  • @carlosmejia5728

    @carlosmejia5728

    4 жыл бұрын

    @Robert Slackware ... he really meant "the center of all forces"

  • @olivialambert4124
    @olivialambert41244 жыл бұрын

    "All of you air bearing enthusiasts out there". Well thats certainly a hobby I'm unfamiliar with, I'll have to admit.

  • @justinjimenez3760

    @justinjimenez3760

    4 жыл бұрын

    there's literally tens of us!

  • @eliotdayley518

    @eliotdayley518

    4 жыл бұрын

    I want a computer mouse with an air bearing.

  • @Vaaaaadim

    @Vaaaaadim

    3 жыл бұрын

    @@justinjimenez3760 DOZENS kzread.info/dash/bejne/nn-dx4-vl7itlKw.html

  • @Gamerock82

    @Gamerock82

    3 жыл бұрын

    @@justinjimenez3760 elevens now :D

  • @MrHelpingHand

    @MrHelpingHand

    3 жыл бұрын

    @@eliotdayley518 Quantum computers will ship with them

  • @HarvardBob
    @HarvardBob4 жыл бұрын

    Excellent topic. Many years ago I used stainless steel air bearings spindles in manufacturing of rigid magnetic disk media with extremely low vibration and runout requirements. One recommendation is to make sure your high pressure air supply is very clean and have filters and traps for particles, oil and moisture contamination to prevent bearing crashes. This is a bigger problem when you are rotating spindles at high rpms and not so much in these examples.

  • @pmk2

    @pmk2

    4 жыл бұрын

    If you don't mind me asking: What kind of magnetic media was it? I have a few older 15mb platters from a DEC mainframe computer, is that what you mean by rigid disk media?

  • @HarvardBob

    @HarvardBob

    4 жыл бұрын

    pmk222 Yes, These were 14” platters. The discs were placed on the air bearing spindles, spun up to 3600 RPM and the flying write heads were loaded on the disc surface. A linear voice coil actuator would step and write a servo pattern. Depending on the the capacity, one to 7 platters were mounted into a cartridge for a single or a a “pack” with multiple platters. The capacity you mention sounds about right. This was in the mid-eighties where it was longitudinal recording with ferric oxide on aluminum substrates. Interesting side note: the “flying heads” used in all magnetic media also use the air bearing principle. Back in the 80s the flying heights were around 25 micro inches. Today’s heads can fly as low as 3 nano inches. Together with glass substrate, deposited magnetic films, better head and electronics makes rotating magnetic media a viable storage medium. Areal density has increased many orders if magnitude and are only recently starting to be replaced by SSD. Fun Fact: A removable 8 inch cartridge I worked on in 1987 would store 20MB of information or only 2 digital photographs in today’s typical application.

  • @antonhelsgaun

    @antonhelsgaun

    4 жыл бұрын

    @@HarvardBob Out of curiosity, do you actually use micro and nano inches?

  • @HarvardBob

    @HarvardBob

    4 жыл бұрын

    Anton Helsgaun Yes, micro inches was the unit of measurement used. When I was working in the mid-eighties they were transitioning to 5 1/4 inch drives because of the growing IBM PC market. The flying height of the heads is a major factor in increasing the areal density of the bird stored in bits/inch^2.

  • @cogoid

    @cogoid

    4 жыл бұрын

    @@HarvardBob Did you use laser interferometers to measure the head position, or were very high resolution rotary encoders already available?

  • @Nighthawkinlight
    @Nighthawkinlight4 жыл бұрын

    That flat sided 3d printed part held up to 80psi you say? Apparently I really underestimate the strength of 3d prints. Really need to mess with them more, along with lost pla aluminum casting.

  • @MrTrilbe

    @MrTrilbe

    3 жыл бұрын

    putting a finished print in an Acetone vapor chamber for a few also helps or painting acetone over the surface, but you need to be printing with PLA.

  • @ninjamaster7907

    @ninjamaster7907

    3 жыл бұрын

    @@MrTrilbe ABS

  • @ElmerFuddGun
    @ElmerFuddGun4 жыл бұрын

    It's like an air hockey table but running backwards.

  • @rizdalegend

    @rizdalegend

    4 жыл бұрын

    ... and forwards.

  • @OliverUnderTheMoon

    @OliverUnderTheMoon

    4 жыл бұрын

    I thought of this concept earlier this year but with a drone motor for thrust and some 11 year old madlad has already done it: kzread.info/dash/bejne/eJmc1MpmfpCWadI.html There is a commercial version too but apparently it's a bit sht

  • @arthurwalraven1020

    @arthurwalraven1020

    4 жыл бұрын

    @@OliverUnderTheMoon What about using some chemical source for the gas? Sodium azide is the first thing that comes to my mind... But the weight of the puck would vary.

  • @Vaasref

    @Vaasref

    4 жыл бұрын

    @@arthurwalraven1020 As would the gas output, it should be possible to balance the two.

  • @arthurwalraven1020

    @arthurwalraven1020

    4 жыл бұрын

    @@Vaasref Sure. I was concerned with the mass variation because of the player's interaction with the puck, though. The speed wouldn't be consistent throughout the game.

  • @ahfreebird
    @ahfreebird4 жыл бұрын

    I run a Zeiss CMM that uses air bearings. The 33 ton granite table is supported by them, all three axes are supported by them. They also make excellent vibration insulators, they were running a dirt compactor directly behind the room it's in, shaking all the tin on the building like mad, but the table had no vibration transferred to it. As you mentioned, it must be kept clean, as otherwise it would grind dust into the granite.

  • @cogoid

    @cogoid

    4 жыл бұрын

    Do you mean air cushions used for vibration isolation? Usually those are somewhat opposite to the air bearings -- an air bearing is usually desired to be very stiff to maintain the air gap exactly the same despite varying load (very high spring constant). Supports for vibration isolation are the opposite -- they allow movement of the support, but still provide the same force (very small spring constant).

  • @sleeptyper

    @sleeptyper

    4 жыл бұрын

    @@cogoid Air bearing is by nature very shock isolating - any vibrations from the base are transferred to the air mass that then purges out thru the gap between base and load. If it was possible to use Schlieren imaging, you could see the vibrations as disturbances at the air outflow instead of being transferred to the load. Ofcourse with too high amplitude you can send the load to lunar orbit, but then vibrations are least of your worries...

  • @whitcwa

    @whitcwa

    4 жыл бұрын

    @@sleeptyper Except the air gap is quite small. For a flat horizontal bearing, there would be excellent isolation in the horizontal plane and little isolation in the vertical plane.

  • @sleeptyper

    @sleeptyper

    4 жыл бұрын

    @@whitcwa That is true when the air gap is completely flat, but some commercial bearing systems use grooves to increase the air mass. The more you have compressible fluid between your surfaces, the better dampening. A hovercraft is very good example of that.

  • @whitcwa

    @whitcwa

    4 жыл бұрын

    Grooves don't increase the gap. Dampening for rigid air bearings is limited to the gap size. Hovercrafts use flexible skirts to keep the gap small.

  • @BIGWIGGLE223
    @BIGWIGGLE2234 жыл бұрын

    If you ever see someone that works in a forging factory, you'll notice just how black they get. All you gotta do is just pull into the parking lot and you'll get dirty. That's bc they use a graphite lubricant that is constantly sprayed into the molds. Every once in a while we would run a part that needed extra lube ran and that meant an extra guy holding a wand in the molds. That shit gets everywhere if that guy isn't fast and gets that wand crushed in the mold. I've went home and had to literally shower in my front yard before I was allowed in the house.

  • @ginglyst

    @ginglyst

    4 жыл бұрын

    some practical joker has put graphite in someones work shoes, by the end of his shift he had graphite all up to his neck

  • @rusty6172

    @rusty6172

    4 жыл бұрын

    sounds great for the lungs :^0

  • @BIGWIGGLE223

    @BIGWIGGLE223

    4 жыл бұрын

    I wouldn't think it's too bad or much worse than anything else we breath in daily. Our bodies get rid of most "debris" and chemicals pretty easily. It's the heavy metals that you have to be extremely careful with.

  • @snakosaurus

    @snakosaurus

    4 жыл бұрын

    @@BIGWIGGLE223 Don't forget about needle-like stuff, around 10 micron long and 10:1 length to diameter. This is what causes silicosis. Graphite is no that though.

  • @Garganzuul

    @Garganzuul

    4 жыл бұрын

    @noxxi knox en.wikipedia.org/wiki/Coalworker%27s_pneumoconiosis

  • @TheJttv
    @TheJttv4 жыл бұрын

    Applied Randomness strikes again with top quality content.

  • @senselessnothing

    @senselessnothing

    4 жыл бұрын

    *Applied Fancy Projects

  • @whitcwa
    @whitcwa4 жыл бұрын

    The old reel-to-reel 2 inch videotape recorders used an air bearing for the rotating heads, but it wasn't graphite. Watching the ball rolling reminds me of the "kugel fountain" installations at science museums where a large granite sphere floats on a water bearing. The largest is over 2.6m (104") diameter.

  • @lazyh-online4839

    @lazyh-online4839

    4 жыл бұрын

    Correct, most air bearings at least used to have a single orifice and precisely lapped bearing surfaces the issue is that ok start up their was no path from the nozzle to the rest of the bearing surfaces, and if the bearing surfaces was cupped slightly to allow air flow across the entire surface it would cause a pistoning effect since air is compressible and the cupped bearing surfaces would act as compressible Chambers. Don't know if that makes sense but I'll link some images to better illustrate this. Graphite and other porous air and porous hydrostatic bearings avoid this problem by placing the "nozzles" across the entire surface and so don't require cupped surfaces or channels carved into the block and almost completely eliminate that bouncing effect. Porous vs orifice bearings images.app.goo.gl/etez3FPjPAiAqb4e8 Various styles of orifice bearings and pressure distribution compared to porous bearings. images.app.goo.gl/NCrUZvuSERCTHPVw6

  • @ahobimo732

    @ahobimo732

    4 жыл бұрын

    It seems like using a noncompressible liquid would solve a lot of potential problems with air bearings. Water isn't compatible with most metals, but oil would work. But this is the basic principle used in journal bearings already. I wonder if pumping the oil through a channel as in air bearings would reduce the friction at all. I think at the very least it would reduce stiction.

  • @lazyh-online4839

    @lazyh-online4839

    4 жыл бұрын

    @@ahobimo732 they already do that, both with orifice and porous media style of bearings, it's already used in more precision bearings and components than air bearings because of the rigidity and is often pressurized to much higher pressure levels (some go a couple thousand psi if I remember right). Pretty much every single surface grinder out there uses the oil version of air bearings.

  • @ahobimo732

    @ahobimo732

    4 жыл бұрын

    @@lazyh-online4839 That's pretty neat! I did not know that. High precision industrial manufacturing (tool-making and the like) is wild stuff.

  • @lazyh-online4839

    @lazyh-online4839

    4 жыл бұрын

    @@ahobimo732 it's called hydrostatic. The 4r-h spindle seems to be a popular spindle that uses that pressurized oil film, you can find a few videos of that spindle being tested here on KZread.

  • @setha6096
    @setha60964 жыл бұрын

    Yes! I have wanted to make air bearings for a while but haven't tried yet. This is awesome!

  • @robmeades2272
    @robmeades22723 жыл бұрын

    That is amazingly useful. I've been wondering how to make a good air bearing without precision machinery and you have made it utterly obvious how easy it can be. Thank you!

  • @DidntKnowWhatToPut1
    @DidntKnowWhatToPut14 жыл бұрын

    Forget ice skating, I want air bearing skating to become a thing.

  • @ganjalfthegreen5312

    @ganjalfthegreen5312

    4 жыл бұрын

    This is gonna be dusty. VERY DUSTY

  • @robbiejames1540

    @robbiejames1540

    4 жыл бұрын

    I think that the lack of friction in all directions would make it very difficult to actually go, as you push against the sides of ice skates. It would be amazing if you could go quickly though.

  • @wiros8101

    @wiros8101

    3 жыл бұрын

    Or a graphite hockey table. Imagine how nice that would look.

  • @lst1nwndrlnd
    @lst1nwndrlnd4 жыл бұрын

    Wet cutting graphite is optimal.being conductive fine dust It can also wear motors prematurely.

  • @peglor

    @peglor

    4 жыл бұрын

    That's why the urban myth about the cosmonauts using pencils while NASA spent millions on the space pen (Which they also didn't do) is wrong on all counts. Conductive dust floating into space shuttle electronics won't end well. Not really an issue with modern encapsulated PCBs though, but normal ball point pens and felt tip pens work perfectly in zero gravity, so no reason to develop any new tech at all for this.

  • @waylandsmith

    @waylandsmith

    3 жыл бұрын

    @@peglor They did use pencils, but they were grease pencils.

  • @armonc
    @armonc4 жыл бұрын

    This just shed a whole new light on hand tooling for me. Amazing!

  • @repalmore
    @repalmore4 жыл бұрын

    Don't think I'll make an air bearing but love that you put up this video. You do such a good job of balancing the massive amount of detail and keeping the video moving along. Keep up the great work.

  • @darinareyacrazyman1505
    @darinareyacrazyman15054 жыл бұрын

    Great video on a very interesting subject. On retaining the puck type bearings in their holders. I once was tasked with making some threaded Graphite cylinders. I set the blanks up in the lathe just the same as a conventional single point threading operation. However instead of a cutting tool I used a 60* profile grinding wheel in a pencil grinder. The threads were a 3" diameter x 16 tpi and were ground in a single pass. This same technique could be used to mount the Graphite pucks in the their holders, with the the only adhesive being used for sealing.

  • @AS-nx2uf
    @AS-nx2uf4 жыл бұрын

    And for the finest surfaces match, sandblasting the master would be probably the best way of getting super fine but still abrasive enough :)

  • @MattBaker1965
    @MattBaker19654 жыл бұрын

    Stunning the massive returns for minimal effort. Well done

  • @artmckay6704
    @artmckay67044 жыл бұрын

    Sweet! I love your approach. It's such a pleasure to see a genuine thinker in action :)

  • @electronicsNmore
    @electronicsNmore4 жыл бұрын

    Fantastic video! You probably could've used a small suction cup on the steel ball connected to a rod and cordless drill to take down the graphite.

  • @Gamerock82

    @Gamerock82

    3 жыл бұрын

    Would be really quick and the other hand can operate the vacuum cleaner for the dust, keeping the grooves / flutes clear.

  • @xidarian

    @xidarian

    2 жыл бұрын

    I thought the same thing once I saw him using the ball as a tool.

  • @dongchen7940
    @dongchen79404 жыл бұрын

    Very interesting experiment. I appreciate you sharing your experience. Cutting groove in bearing ball is an great idea I have never think of. I think if cutting grooves and sand off all the Sharp edge, it will make a good lap. I am also interested in graphite air bearing. My experience is slightly different from yours.I found it easy to make an air bearing that float but quite difficult to make it useful, namely have the stiffness. According to literature the air film stiffness will greatly decrease if the thickness over 10 micrometer or the flatness is worse than half of the film thickness. I also found Poco's graphite perform better than regular EDM graphite.

  • @mkilptrick
    @mkilptrick4 жыл бұрын

    Fascinating topic I never expected to come across. Thank you for opening my mind.

  • @ChrisDePrisco
    @ChrisDePrisco4 жыл бұрын

    Thanks for this! I was wanting to start to experiment with air bearings a few weeks ago but thought they used a special type of graphite that was porous enough. They probably do for performance but it's awesome to learn that standard graphite works well enough.

  • @marcmarc172
    @marcmarc1724 жыл бұрын

    Love the content! The videos are always worth the wait!

  • @EclecticBuddha
    @EclecticBuddha4 жыл бұрын

    Idk why I find flywheels so mesmerizing. I wish they were as ubiquitous a desktop toy as newtons cradles.

  • @MLGJuggernautgaming
    @MLGJuggernautgaming4 жыл бұрын

    Always amazed by the depth and education of your videos

  • @liferetriever4188
    @liferetriever41884 жыл бұрын

    You conjure up amazing things with simple stuff. Just like magic. I am hooked on your channel.

  • @wallybe2946
    @wallybe29464 жыл бұрын

    Awesome Thank-you for your time and effort

  • @francoisdastardly4405

    @francoisdastardly4405

    4 жыл бұрын

    Absolutely !!!! +1

  • @captain_ironbutt
    @captain_ironbutt4 жыл бұрын

    I want to see this implemented in the world's loudest, least power efficient trackball. Boy would I flick it.

  • @crabmansteve6844
    @crabmansteve6844 Жыл бұрын

    When you pulled out the bearing ball with the slits cut into it I fell in love. Its a spherical reamer now. That is an elegantly simple solution. As for the porosity of the FDM printed parts, a light brushing or misting of a acetone or another solvent does wonders to smooth and seal the surface as long as you're using a compatible filament like ABS, it doesnt work on PLA, just makes it gummy.

  • @Palmit_
    @Palmit_4 жыл бұрын

    I love all your vids and explanations Ben, but this tickled me. "...so if you have really thick glass laying around.. " cut to: meter thick , almighty lump of glass, just laying around.. :D

  • @ifell3
    @ifell34 жыл бұрын

    Really enjoyed this. I think CNC kitchen done a video with epoxy and different glues on the out side of prints not to much avail.

  • @lengaming1651
    @lengaming16514 жыл бұрын

    I litterally just watched the consept video posted 10 years ago yesterday, and now this!

  • @jacobmaddy2884
    @jacobmaddy28844 жыл бұрын

    Thank you. I very much appreciate the personal research you have done and been kind enough to share. I have some turbine applications that this would be perfect for.

  • @Tomasitoke
    @Tomasitoke4 жыл бұрын

    First thing that came to mind: Best trackball ever

  • @creepyloner1979

    @creepyloner1979

    4 жыл бұрын

    worst trackball ever. you don't want a trackball that's just constantly creeping along no matter how carefully you try to stop it or that rolls back to whichever side has a fraction of a milligram less grime on it.

  • @Tomasitoke

    @Tomasitoke

    4 жыл бұрын

    ​@@creepyloner1979 But wouldn't it be possible to adjust the amount of slipperiness by changing the amount of air provided?

  • @scottwillis5434

    @scottwillis5434

    4 жыл бұрын

    @@Tomasitoke sure. You could control it with a trackball...

  • @daos3300

    @daos3300

    4 жыл бұрын

    Tomasitoke and would you want a trackball that has to be hooked up to an air compressor?

  • @Tomasitoke

    @Tomasitoke

    4 жыл бұрын

    ​@@daos3300 In my shop I already have an air compressor running all the time, and a tiny hose is not a big deal for a stationary mouse. For home use you could probably use a fridge compressor which you can get for free, maybe even a couple of them if flow is insufficient

  • @theunaphotobomber
    @theunaphotobomber4 жыл бұрын

    You need to check out Rob Renzetti if you haven't already. He's the best at fine precision tooling that I've seen yet. I think you'd love it.

  • @KallePihlajasaari
    @KallePihlajasaari Жыл бұрын

    Great to see your experience with hand tooling of graphite. It allows the messy work to be done outside. I have a project coming up where I want to make a small graphite mould for forming the end of a glass test tube into a more complex shape.

  • @thegrumpytexan
    @thegrumpytexan4 жыл бұрын

    Fascinating. Reminds me of the old Xynetics flatbed plotter I used to work on back in the 90's, that was developed sometime around the 60's or 70's. It used a magnetic head that was attached to the underside of the top bed, and an air pump was used to push it off just enough to where the head could move freely. Motion was not controlled by X/Y motors, but by pulsing electromagnets to "crawl" across the underside (and at a surprisingly fast speed.)

  • @cogoid
    @cogoid4 жыл бұрын

    Great to see it done with such simple tools! To see what these things are capable of -- Dan Gelbart has built an air bearing CNC lathe in his basement which has precision of 1 micrometer. ("High precision air bearing CNC lathe and grinder " video on his channel.)

  • @lpjunction

    @lpjunction

    4 жыл бұрын

    It is interesting to watch Dan Gelbart's series of mechanical stuff related video, then I wonder why someone has the time and effect to work on this wonderful series. I looked up more about Dan. This gentleman founder an optics company which was later sold for a very large sum of money.

  • @cogoid

    @cogoid

    4 жыл бұрын

    @@lpjunction Dan Gelbart had a very interesting career. He started as an electronic engineer, developed some very advanced and very successful communication equipment, then invented many other things -- educating himself along the way on how to do things like optical design, for example. And even though along the way he has created many companies, and is quite wealthy, he is still working with his hands in his basement machine shop -- where most of his products were created. He is also teaching at a college and that's why he has that video course on prototyping on KZread. He is sharing his experience as a contribution to the community. There are lots of things in his mini-lectures that even an experienced craftsman may find interesting -- but of course they are just short videos on a subject which one has to learn by doing things with one's own hands over quite a long time -- just like Dan did.

  • @COBARHORSE1

    @COBARHORSE1

    4 жыл бұрын

    Dan Gelbart's video: kzread.info/dash/bejne/pXqmuMaof8vbYbQ.html

  • @TheFlyMinecraft
    @TheFlyMinecraft4 жыл бұрын

    I just heard of air bearings yesterday in some Videos a while back. and then I see your Video recommended : "Oh wow Applied Science made a Video about that topic.. neat, musst been a while ago..wait only 300 View...so few Views on such an Video...." *looks at the upload date, expects an old date*: "wait whut?! Uploaded right Now ?!" All those other Videos were from back 2011 so i expected the same xD

  • @aa55claa55cl

    @aa55claa55cl

    4 жыл бұрын

    same experience yesterday .................... what happened ?

  • @TheFatblob25

    @TheFatblob25

    4 жыл бұрын

    kzread.info/dash/bejne/noOIudpvadDNmLA.html Same experience today! About 4 hours ago, I was mystified as to what the material they were using for air bearings & low & behold just now! Brilliant stuff...

  • @MushookieMan

    @MushookieMan

    4 жыл бұрын

    I just heard of air bearings a few days ago... Now I know that KZread is recommending me videos based on what my subscriptions have sitting in their unpublished videos.

  • @BIGWIGGLE223

    @BIGWIGGLE223

    4 жыл бұрын

    The same thing with me. The one I watched was an obvious manufacturers selling video. And then this is the very first thing to pop up in my feed. Coincidence?!?! I doubt it.

  • @mashedpotatoes5323

    @mashedpotatoes5323

    4 жыл бұрын

    Air bearings are the new coolest thing

  • @AlbertLebel
    @AlbertLebel4 жыл бұрын

    Absolutely fascinating. I'm glad I stopped by to watch this. Keep up the good work

  • @aa55claa55cl
    @aa55claa55cl4 жыл бұрын

    he is the only youtuber whom i would like to spend more than 5 mins on one video

  • @ficolas2
    @ficolas24 жыл бұрын

    so, its basically air hockey but with way way way more holes

  • @creepyloner1979

    @creepyloner1979

    4 жыл бұрын

    i was thinking the same thing. might get into the luxury granite air hockey table business. :P

  • @aa55claa55cl
    @aa55claa55cl4 жыл бұрын

    omggggg, my youtube suggestion has tons of air bearing coming out of nowhere yesterday , and u have a video today .......................... what what what

  • @Ayestosea

    @Ayestosea

    4 жыл бұрын

    It's hinting that hovercars are the future...gotta have a way to get around once tptb nuke everything to glass.

  • @travismiller5548
    @travismiller55483 жыл бұрын

    I've carved some graphite in my day. Glass blowers call those marble molds. Another great way to machine that shape is to weld a shank to a large washer- call that the north pole. slightly sharpen the southern circumference, creating two cutting edges like a drill bit. Chuck up on the shank in a drill press. I really liked your garnet abrasive idea- thanks for sharing!

  • @moinshaikh2265
    @moinshaikh22654 жыл бұрын

    Lovely. Lovely. Lovely. Wonderful. O man i can easily understand how much you have spent your precious time and effort to get this job don. Once again LOVELY. Thanks for this wonderful video.

  • @googacct
    @googacct4 жыл бұрын

    I wonder if this would work with MDF. It is porous as well. I have used it to make a vaccum chuck for my cnc router. No reason why the air can't go the other way as well. I would be wary of graphite dust getting around the shop since it is conductive. I could see all sorts of problems starting to happen with electronic devices if there is much a of a build up.

  • @janekkouril476

    @janekkouril476

    4 жыл бұрын

    idk, but mdf is probably too coarse to be smoothed like that

  • @The1belal

    @The1belal

    4 жыл бұрын

    Very good point

  • @TheJensPeeters

    @TheJensPeeters

    4 жыл бұрын

    In addition to being way smoother, the dust from graphite is partly graphen and graphite, which are both due to their cristalline structure great lubricants

  • @custos3249
    @custos32494 жыл бұрын

    You call it crude, but that abrasive method is literally the same basic idea behind lapping engine valves

  • @origamihawk

    @origamihawk

    4 жыл бұрын

    Scraping is a super crude way to flatten something and yet it's insanely accurate, always crazy how precision machines are made.

  • @custos3249

    @custos3249

    4 жыл бұрын

    @@origamihawk It's almost as if friction were a fundamental force

  • @dittilio
    @dittilio3 жыл бұрын

    That's a really beautiful shot of the sunbeam in the workshop.

  • @gustaveluna9349
    @gustaveluna93493 жыл бұрын

    Hi, excellent purpose! Keep going, most of the best come from people like you. Big respect.

  • @mduckernz
    @mduckernz4 жыл бұрын

    I'm warning you now: do not operate electronics you really like and want to keep in a place where you machine graphite. Trust me. They WILL die if you do not have a very good extraction system.

  • @konstantingrudnev8374

    @konstantingrudnev8374

    4 жыл бұрын

    @Neocaradina graphite conducts electricity. graphite dust can short-circuit power electric lines or power plant , that's why there's such thing in military as graphite bombs

  • @eideticex

    @eideticex

    4 жыл бұрын

    @Neocaradina Graphite is conductive. You can make a really effective buck converter (a device that lowers voltage) out of a pencil. Just cut the graphite free of the pencil, attach your positive and negative leads to each end and place your power tap wire onto the graphite. If you place the tap halfway, you get half the voltage. It's a linear circuit so percentage of distance across is percentage of voltage you get out of the tap.

  • @entcraft44

    @entcraft44

    4 жыл бұрын

    @@eideticex Not every device that lowers voltage is a buck converter. What you describe is a voltage divider, which wastes significant amounts of power. A buck converter is way more efficient.

  • @norbs

    @norbs

    4 жыл бұрын

    Glad you warned him because *surely* he doesn't know that

  • @rich1051414

    @rich1051414

    4 жыл бұрын

    @@eideticex That is a resistive divider... not a buck converter.

  • @outputcoupler7819
    @outputcoupler78194 жыл бұрын

    Very cool. Planning to incorporate these into any projects in the future?

  • @j.m.1389
    @j.m.13893 жыл бұрын

    You have me wanting to make one when I don't have a need for one. It was a VERY interesting video!

  • @schitlipz
    @schitlipz4 жыл бұрын

    Dude, you make the BEST engineering videos. You speak well, cover all the bases, tie up in a bow... like really good stuff. I've never not enjoyed one of your vids. Hope you had a lovely Christmas, and have a Happy New Year too!

  • @larrybud

    @larrybud

    2 жыл бұрын

    No doubt. The fact that the takes are in a long segments is testament to his knowledge and speaking ability. There's a few channels I watch that have good content, but the presentation stinks because the presenter can't say more than 10 words without an edit.

  • @seeigecannon
    @seeigecannon4 жыл бұрын

    Huh, it would be interesting to make a balancing fixture for my surface grinder like this. No more having to verify the working table is sufficiently level. Would also remove the friction between the test arbor and the blocks it is resting on.

  • @Ayestosea

    @Ayestosea

    4 жыл бұрын

    Hmmm...how about some air bearings on the bottom so you can just roll the mill around the shop? Would also look hilarious.

  • @darkracer1252

    @darkracer1252

    4 жыл бұрын

    @@Ayestosea have you not been watching this video at all or what?

  • @landonkryger
    @landonkryger4 жыл бұрын

    Love, the video. Sorry to be pedantic, but technically, those 2 inch spheres are bearing balls. Ball bearings are the things that contain several bearing balls. I want this to sound like a fun trivia fact, but I'm sure it doesn't read that way on the internet.

  • @swc0ll

    @swc0ll

    4 жыл бұрын

    Well, if the bearing device consists of a single ball only, it is both ball bearing and bearing ball, isn't it? :)

  • @maxprophet2401

    @maxprophet2401

    4 жыл бұрын

    They are a B.B. istn't they?

  • @jacewalton6677
    @jacewalton66774 жыл бұрын

    Everytime I get interested in something you do an in depth video on it

  • @TheTsunamijuan
    @TheTsunamijuan4 жыл бұрын

    When it comes to sanding tooling. I have been printing sanding tools for curves and compound curves lately. Yes industrial tension/compression loading sanding tools that let you set a radius are nice. But the ability to drop a radius into fusion and then print a custom radius sanding tool really saves time. Plus for circular situations you can add a chuck/racket extension port and then use a drill/die grinder/ or drill press with it.

  • @KeesHessels
    @KeesHessels4 жыл бұрын

    i need a 200k rpm drill mechanism (on the cheap as well) you just handed me an idea... thanks..

  • @Ayestosea

    @Ayestosea

    4 жыл бұрын

    Ive done the math for a 2in dia rod, that's 130,000 rpm max so Im assuming if you are aiming for a particular rpm you should aim for a particular size for the rotational assembly you plan on floating. I can pass on the formula or figure out what dia you need if you reply as I know youtube doesn't always give notifications for comments.

  • @KeesHessels

    @KeesHessels

    4 жыл бұрын

    @@Ayestosea Awesome, II would love to know the formula, thanks that would be great :) , i am going to use max 1 inch, probably something like 12 mm (about 1/2 inch)

  • @Ayestosea

    @Ayestosea

    4 жыл бұрын

    @@KeesHessels Seems I might not be entirely correct. But I would still design it so any surface with airflow doesnt go supersonic. I dont exactly understand it 100% like if the film thickness is thin and the air "roll" does that allow for doubling to 260,000 rpm without going supersonic or if the rolling itself is limited by the air density blah blah

  • @sleepib
    @sleepib4 жыл бұрын

    Would this type of bearing work for something like a zero backlash nut on a ballscrew, or are the forces too high?

  • @bschena

    @bschena

    4 жыл бұрын

    yes, an old professor of mine invented (and patented) a "hydrostatic leadscrew" back in the '80's: patents.google.com/patent/US5090265A/en

  • @FilterYT

    @FilterYT

    4 жыл бұрын

    Weird coincidence, the patent expired today (or maybe I don't know how to read a patent properly - quite likely).

  • @sleepib

    @sleepib

    4 жыл бұрын

    @@FilterYT I think it would have been about 10 years ago.

  • @MBkufel
    @MBkufel4 жыл бұрын

    How did I not find this channel earlier. While watching the vid, YT suggestions show like 10 of your projects and judging by titles, all are equally interesting and required much skill to make.

  • @4.0.4
    @4.0.44 жыл бұрын

    I love merch that's more creative than just shirts. E.g., those beakers.

  • @johnmccanntruth
    @johnmccanntruth4 жыл бұрын

    That was really cool. Any chance you might make some practical application things? Weird question I realize, but I think you get my meaning. It would be cool to see these put to some good use... Merry Christmas!

  • @randompanda876

    @randompanda876

    4 жыл бұрын

    Air hockey!

  • @Berkana

    @Berkana

    4 жыл бұрын

    If you have an item that you need to re-position on a smooth surface that you don't want to mar (such as the granite or glass slab), putting it on air bearings would let you move it around. Putting suction cups on it that you can then use to hold it in place when you're done moving it would be a nice touch.

  • @lyneham

    @lyneham

    4 жыл бұрын

    Would it be practical to use these bearings for a large flywheel to store electricity instead of using batteries? ie: to use a motor to add angular momentum and when you want to draw energy from it to use a generator to subtract angular momentum from it

  • @victornpb
    @victornpb4 жыл бұрын

    When you said it has zero wear, doesn’t the air “erode” the graphite over time?

  • @cookieninja2154

    @cookieninja2154

    4 жыл бұрын

    Erosion by air is a thing, but I've only heard it seriously discussed in a time frame of milions of years. Same with the claim that it is frictionless, it isn't but air friction (diffrent from air resistance) is only relevant at very high velocities.

  • @jeremiahzagala5608

    @jeremiahzagala5608

    4 жыл бұрын

    I was think the same thing.

  • @Splarkszter
    @Splarkszter12 күн бұрын

    I love your channel. I just keeo learning more and more awesome awesome stuff that i can apply to my own problems. THANK YOU SO MUCH. You help me get so many new ideas. Thank you sooooo much.

  • @HuygensOptics
    @HuygensOptics4 жыл бұрын

    This file making method is pretty brilliant, as is the rest of the video by the way. Instead of vacuum, you can also use magnetic preloading if the sliding object is ferro- or paramagnetic. Is should work on the ball.

  • @saccaed
    @saccaed4 жыл бұрын

    this makes me want to make an air bearing for my trackball mouse.

  • @putteslaintxtbks5166
    @putteslaintxtbks51664 жыл бұрын

    Your Waterjet cutter would probly be less mess for cutting graphite.

  • @dorianmccarthy7602

    @dorianmccarthy7602

    4 жыл бұрын

    That's a brilliant idea! any excuse to see that thing in action again i'm happy with.

  • @Llohr

    @Llohr

    4 жыл бұрын

    Then how does he lubricate the bandsaw?

  • @dorianmccarthy7602

    @dorianmccarthy7602

    4 жыл бұрын

    @@Llohr Graphite lubricant - badum tss!

  • @DrFiero
    @DrFiero4 жыл бұрын

    Photocopiers being scrapped is a great source of large, thick, very flat glass. Bonus, they're usually cheap or free!

  • @mechadrake
    @mechadrake4 жыл бұрын

    Found it very interesting. Never learned about air bearing in my engineering courses.

  • @chemusvandergeek1209
    @chemusvandergeek12094 жыл бұрын

    12:08 If efficiency becomes important, seal the exposed surfaces that you don't want to leak. Perhaps simply paint them.

  • @scottwillis5434

    @scottwillis5434

    4 жыл бұрын

    After selecting a paint with strictly limited penetration? Would that be an issue, probably depends on how much the binder wicks into the surface.

  • @chemusvandergeek1209

    @chemusvandergeek1209

    4 жыл бұрын

    @@scottwillis5434 That, sir, is an interesting animal once described by Eristhones: an ellifino.

  • @mxcollin95
    @mxcollin954 жыл бұрын

    This is really cool but what would you actually use these fragile bearings for?

  • @OtakuSanel

    @OtakuSanel

    4 жыл бұрын

    they aren't really that fragile. you use them when you need super high precision with zero run out. semiconductor fabrication uses them as an example but there is also some videos on youtube i looked at earlier where someone made a diy lathe with hyper precise tolerance to make parts that seem like magic.

  • @Wtfinc

    @Wtfinc

    4 жыл бұрын

    high speed, high heat aplications. Where oil cannot be and cintered bronze wont cut it, or mag lev is not feasible.

  • @alexbowlen6345

    @alexbowlen6345

    4 жыл бұрын

    You could totally make a super efficient cardboard/foamboard cnc head with an air bearing like that.

  • @johnpossum556

    @johnpossum556

    4 жыл бұрын

    I would think they'd be good for balancing props and other precision balance work like HS motor armatures.

  • @crackedemerald4930

    @crackedemerald4930

    4 жыл бұрын

    Fast spinny things, i would use them for tiny air turbines.

  • @denispol79
    @denispol794 жыл бұрын

    I just learnt a week ago about this type of bearing, and here you go - a video from AppliedScience :)

  • @socksincrocks4421
    @socksincrocks44214 жыл бұрын

    A pleasure as always. Thank you Sir

  • @ih8tusernam3s
    @ih8tusernam3s4 жыл бұрын

    What's that quartz/borosilicate tube for?

  • @AppliedScience

    @AppliedScience

    4 жыл бұрын

    That is a tube furnace for making carbon nanotubes (video not made yet. In fact, nanotubes not made yet :). Ironic that it is also covered in carbon dust from the current project.

  • @3er24t4g1

    @3er24t4g1

    4 жыл бұрын

    @@AppliedScience can an aquarium air pump be used to supply air for small bearings? Like for M6 or M8 rods?

  • @joetransue

    @joetransue

    4 жыл бұрын

    www.dictionary.com/browse/water--water-everywhere----nor-any-drop-to-drink

  • @ih8tusernam3s

    @ih8tusernam3s

    4 жыл бұрын

    @@AppliedScience Thanks for taking the time to reply. I can't wait to see that video!

  • @VMac-eg7fb

    @VMac-eg7fb

    4 жыл бұрын

    @@3er24t4g1 That would produce pulsed air which would ruin precision, use compressed air for a consistent air supply.

  • @wtechboy18
    @wtechboy184 жыл бұрын

    I have a question. If you were to take a thin drillbit, on say a dremel or drill press, and drill out very tiny air channels in the *back* of the block, that came up just a tiny bit shy of the bearing surface on the graphite block, would it possibly lower the input pressure required? It seems like you need quite a bit of pressure to get the air passing through the block at a high enough flow rate to keep things levitated off the block, and I figured reducing how much graphite you need to force the air through might reduce the pressure requirements. edit: also, thanks for linking the sources for the giant ball bearings and linear shafts. I didn't know I could buy 3" bearings on amazon, and now I'm excited to try this.

  • @vladimirlenin843
    @vladimirlenin8432 жыл бұрын

    Those factory bearing are amazing

  • @stefanhertweck
    @stefanhertweck4 жыл бұрын

    Excellent pragmatism on an (for me) interesting subject :) Thx.

  • @Asdayasman
    @Asdayasman4 жыл бұрын

    "If you're in the market for a granite surface plate-" THAT'S IT! That's the clue for what his current big project is! Everyone, get thinking.

  • @mamupelu565

    @mamupelu565

    4 жыл бұрын

    me stupid dont got it

  • @spaminbox
    @spaminbox4 жыл бұрын

    graphite as gecko tape mold?

  • @crackedemerald4930

    @crackedemerald4930

    4 жыл бұрын

    Too small

  • @chainsawcowboy3179
    @chainsawcowboy31794 жыл бұрын

    I love to see a new video from you! Great work!

  • @sometimessomethings3873
    @sometimessomethings38734 жыл бұрын

    Very nice and detailed enough for the basics

  • @MarkWladika
    @MarkWladika4 жыл бұрын

    "all of you air bearing enthusiasts"

  • @Corporatist

    @Corporatist

    4 жыл бұрын

    All 3 of you

  • @nickhowatson4745

    @nickhowatson4745

    3 жыл бұрын

    1/2 a person

  • @jonbeno9926
    @jonbeno99264 жыл бұрын

    Great stuff! I'm pretty sure putting round hole in graphite will work for a low friction linear guide but will give you a very low radial stiffness bearing. I'm pretty sure you've seen it, but check out New Way's video on radial air bearings using multiple individual bearing elements. kzread.info/dash/bejne/noOIudpvadDNmLA.html This allows you to set the preload of the bearing mechanically, and the stiffness of the bearing is two series springs, the structural loop plus the air bearing stiffness, which can be extremely high for small gaps. The tradeoff is how perfect you need the surfaces and how much load capability you want to remain before grounding the bearing, but I think this should be sufficient to use for a high accuracy grinding spindle for example. Love the content, your stuff is very inspiring!

  • @gudenau
    @gudenau4 жыл бұрын

    So it's like an air hockey table? That's pretty cool.

  • @1992jamo
    @1992jamo Жыл бұрын

    I'd love to see the electrical conductivity between the graphite and steel before and after the air is applied. That way you could see how much contact there is. Awesome vid.

  • @askquestionstrythings
    @askquestionstrythings4 жыл бұрын

    Activate Engineering cheat code...

  • @fredg8814
    @fredg88144 жыл бұрын

    Keep that dust away from sensitive electronics, don’t forget why we use it in EDM

  • @nordicmind82

    @nordicmind82

    4 жыл бұрын

    Yeah. Just chuck a handful of the stuff into the air at a music studio and the horrible sounds that start glitching their way into a repeated stream of bass "clicks" is ready for the club. Making EDM is really easy when you discover hacks like this. Possibly add a sample of someone saying something cool and you're all set.

  • @username4441
    @username44414 жыл бұрын

    the aesthetics on those 2nd gen bearings with the 2 part seal are... quite pleasing.

  • @dancarlson8470
    @dancarlson84703 жыл бұрын

    My new favorite quote..."It's like a bouncing ball...but its an electrical transformer" lol love the videos keep it up Ben!

  • @garethjones6342
    @garethjones63424 жыл бұрын

    Please be aware - some graphite from second hand sellers can come from larger pieces used in reactors or other radiation emitting technology. Some sellers will say radiation free or state its source. Something to be cogent of if you intend to machine the stuff.

  • @unvergebeneid

    @unvergebeneid

    4 жыл бұрын

    Wait, people are selling nuclear waste on Amazon? How did they even get their hands on this stuff? Shouldn't it be buried deep under a mountain or something?

  • @emilalmberg1096

    @emilalmberg1096

    4 жыл бұрын

    This type of graphite is very clean and can only be sold under controlled conditions, some rogue states like to buy it, at sky high prices!

  • @garethjones6342

    @garethjones6342

    4 жыл бұрын

    @@unvergebeneid graphite isn't exactly radioactive waste on the same levels a s things you would think of such as yellowcake or glass matrix wastes; things capable of causing real immediate harm While the graphite might be at or around the safety levels for salable bulk raw materials, you probably don't want to be working it and inhaling itsnincredibly fine dust. ALL THAT BEING SAID - radioactive "safety dose" limits are set with an absurd margin of safety- you could probably take ten times the dose (of most types) through your skin the daily max limit, every day for a year, and be completely fine and unaware anything had even taken place. Interestingly also - if you can find a cheap Geige counter, modern cheap *crap metal* items like.knives and forks are.sometime mildly radioactive. So while having a block of graphite around your house your whole life is likely 99.99999% safe, I wouldn't want a few trillion of those same radioactive.mulecules buried deep in my lungs from not wearing a proper dust mask/using filtration Edit.: sorry about the typing errors; I'm on mobile

  • @unvergebeneid

    @unvergebeneid

    4 жыл бұрын

    @@garethjones6342 Sure, it's not the same as highly radioactive materials but even medical equipment like gloves and stuff that's used with radioactive isotopes is considered nuclear waste and has to go into terminal storage. It's actually the main source of radioactive waste.

  • @garethjones6342

    @garethjones6342

    4 жыл бұрын

    @@unvergebeneid if that is now the case, then great. When I first started working as a glassblower 20 years ago (we use carbon for all sorts of molds and tooling) it was common practice to only buy from certified sellers. Or at the very least avoid buying from small portions sellers from places.like eastern Europe. People in the glassblowing community did tests with geiger counters (or maybe cloud chambers?) And found neutron activated graphite. It would only be dangerous if machines and inhaled... but that's how.you make molds and tools from the stuff. If regulations and sales practices.have changed, I'm glad for it. One less thing to worry about!

  • @beaconofwierd1883
    @beaconofwierd18834 жыл бұрын

    Coating PLA parts in epoxy can actually reduce the strength. See CNC kitchens new video on the subject :)

  • @BRUXXUS

    @BRUXXUS

    4 жыл бұрын

    Still worked for sealing them to be more air tight. But yeah, when he said to maybe add strength I was like.... oh... bad timing. lol

  • @christatler7378
    @christatler73782 жыл бұрын

    About 30 years ago I had an idea to make a turntable for playing vinyl records that used some kind of air bearing. The idea was that if the turntable was isolated from its supports then no vibration would get through. Problem was I never had enough engineering skills and I would never have thought of doing this. Excellent demonstration. Thanks

  • @larrybud

    @larrybud

    2 жыл бұрын

    The best 50 grand you never spent! ;-)

  • @harperwillis5447
    @harperwillis54474 жыл бұрын

    I have been waiting for you to do these for years

  • @mhyzon1
    @mhyzon14 жыл бұрын

    “Air bearing enthusiasts” 😂

  • @GlenBerry

    @GlenBerry

    4 жыл бұрын

    Yeah, we know they're out there. No need to mention them by name. They know who they are. 😉

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