Make Your Own Air Knife!

[Music] how frustrating is it that whenever you reach for a knife these days they're always made out of metal I know right believe you me you're preaching to the some of you might be thinking hey old Tony slow down I got a plastic knife or maybe even a fancy ceramic one oh look at me sure I'll give you that but how much cooler would a knife be if it were made out of thin air well have I got something for you this is an air knife look familiar you may have spotted this in a recent

video you might have even thought I made this up but I assure you this is a very real thing you can buy right now not just some fancy party trick for getting into women boxes that said I may have stretched the truth just a little a smidge this will not in fact cut open a cardboard box well I mean maybe if it was thin cardboard very thin wet cardboard maybe this unassuming little thing however turns ferocious unbridled compressed air from your compressor of all places into a very thin curtain of laminer air it's basically an

air nozzle you you know like one of these for blowing air on stuff but I think it's a lot cooler you know the air knife bit is probably just marketing doing what marketing does otherwise would you watch a video about a laminer flow air curtain maker okay fine so would I turns out it's hard for me to show you what this thing is doing I apologize that the air I happen to be using is invisible but I'm sure we've all used those blade hand dryers like the air hand dryers in bathrooms right first couple of

times you put your hands in there you know it was new it felt really cool but now they ske you out it feels exactly like one of those there's like a line of compressed air blowing across my body uh I mean hands definitely hands so no Dyson didn't invent the air knife at least I don't think he did I didn't actually look that up but these have been around a lot longer than the skey hand dryers these are used in manufacturing and process control in a million different things but mainly three or four they dry

stuff of course imagine you have a big conveyor belt of wet or oily thing ofama jigs an air knife or 15 along the way dry all of the product off they clean Parts blowing away debris out of I don't know machine or molded Parts pcbs they probably don't don't use these in flower mills I imagine but you get the idea they're also used for cooling of course I've even seen them used as literal air curtains that divide rooms there's like a super fun wall of air when you enter and exit some versions of these even

have like magic ionizers built in they Blast Away static electricity from sheet stock you know like potato chip bags that sort of thing before these came along most folks used flat air nozzles or just a lot of regular air nozzles or heck even a pipe full of holes and I'll be honest with you here there are still a lot of flat nozzles out there and pipes with holes don't be calling me out in the comments telling me where you work it's all flat nozzles because I wouldn't be surprised the big advantage of these though over

nozzles or pipes with holes in them is that they use a lot less air it might sound weird but air is silly expensive I have personally worked on entire oneman teams assigned solely to finding and fixing air leaks despite what you might have just heard a few moments ago air nozzles also make a lot less noise for the same amount of drying or cleaning a comparable flat nozzle does if you're still using a flat nozzle in the middle of the office drying your white out do everyone a favor and try an air knife thank me

later on the flip side generally speaking air nozzles can generate a lot more Force than air knives so there are some trade-offs I could go on about these things forever but the reason I get gathered you all here today is I want to try to make my own one thing I've always noticed air knives all tend to be straight like just a stick of air knife one 2 5T long but always straight would this work if we bent it around on itself could we make an air donut and what would it do now hold on

before you unsubscribe yes ring blades are a thing sometimes called ring wipes I think and yes they sure look like round air knives don't they these are used for drying or cleaning round stuff instead of flat stuff pipe tube cables tapeworms that sort of thing but ring wipes send the air in radially or you know maybe kicked back just a little so it's imp pinging on the round thing you're running through it what I'm talking about is bending the air back in on itself sending it back down like axially like a jet engine or a

toilet [Music] I suppose we should talk about what this regular air knife is doing before I start making life complicated this is an xair made in good old Cincinnati fundamentally it's two flat pieces of metal you know sort of flat some features in there air comes in the back and is channeled out of a very small slot on the front side instead of out of a ho like a a nozzle like your blow gun I think this slot should be on the order of magnitude of I don't know two 3 thousand of an inch start

with two maybe a little bigger than two two and A2 help if I just used one Shin yeah I guess about two and a half two to two and A2 that's uh 05 mm I used to think these were crazy high tolerance machined parts and that's what made them so expensive however people are smart usually there is no super flat 2 and 1 half thou machined Gap instead there's some sort of piece of shim stock in here between the two flat parts that sets that Gap that's way easier to make and if you keep the

price High well everybody wins actually let's try to take this apart I kind of rather wouldn't but I'm planning to borrow some Dimensions I was not oh there it is oh wild a plastic shim I want to be very careful with this thing let's see so air comes in the inlet here and fills sort of this plenum see that mil slot in there we've got this shim on here that seals up the back and only lets air out over this small land here right the cap is on there like this I'll just offset it the

shim seals back here keeps the cap lifted about 2 and 1 half thou 2 th whatever that was that we measured only place the air can get out is between those duck lips created by the cap in the body when that very fast sheet of air comes flying out out it's riding along just one wall and does anybody here remember the P Kanda [Music] effect maybe an end view would be a little more helpful we've got the air coming in opposite this that's just a cap a plug air is coming in this side fills up

the body here and the only way out is through this long thin Gap at the top now on its own it would want to just shoot straight out but because we've got a wall on one side we've got that coanda effect thing going on low pressure on one side ambient on the other it bends that jet down and it follows the wall so the air sheet coming out of this air knife is pointing straight down and it's entraining all of the air in the room or around it and pulling it along that entrainment gives it

kind of like an amplifying effect it's sort of blowing more air on your stuff then you're pumping into the back that entrainment over this wide area is what makes these more efficient than just a free jet just a nozzle in open air the bend on the other hand does a couple of things I think I'm no air scientist here keeps the flow laminer for longer compared to just firing one of these into free air consequently keeping the flow of air quieter and more directed this knife here I'm just guessing probably keeps the flow laminer out

to I don't know 8 10 12 in away that's pretty impressive but that brings us back full circle and by full circle I mean I want to try to make a circular air nozzle with the same discharge geometry can't believe I don't have anything round imagine an air knife that looks like this kind of like the ring wipe but unlike the ring wipe I don't want the air to kind of come in radially to wipe the cable I want it to go straight out axially like a jet engine and we'll see what it does if

it does anything at all except make noise and waste air baby if you've ever wondered wondered whatever became of me I'm making air knives in Cincinnati Cincinnati a a a e e ex a i r I thought this was going to be mostly a lathe project but turns out I don't have any 4in round stock also I pulled a fast one on you I was so hung up on finding a 4in cut off I completely forgot about the thickness I started off with this I cut this off and didn't realize how thick it was until

I got to the mil I only really need about 3/4 of an inch yes I could have just sanded this to size with some 400 grit sandpaper but I just dug up a thinner cut off fine print paragraph 2 none of my big drills fit in the mill I've always meant to get tooling that uses some of my drill tapers but I don't have any yes I could have just put the hole in this with an endmill but remember a from a karate chop or maybe a saw the fastest way to get material out of

something is a drill now I'm going to Mill in the ring that becomes the air Plum the air cavity which I also could have done on the lathe but there to cut a Groove into the face you'd need a can anybody guess that's right a face grooving tool and well it's it's just easier here not to mention even though I just mentioned it I'm going to need a bolt hole pattern around these features which historically has always been challenging for me on the [Music] lathe I know I tend to do a lot of tight shots

on this channel I don't usually work on big stuff and I want you to see what I'm doing but for kicks here's what this looks like from a few steps back this mahoe milling machine doesn't have the largest capacity or the mostest horsepower but sure does take up a lot of space for scale here is one 100% totally human earthand the bolt hole pattern went fine not a lot of surprises here these are number 19 drill holes somewhere around 4 mm I plan to tap these M5 you would be shocked at how many M5 screws

I have left over from the C TNC router build but remember that to play it safe I counter board them just cut a little recess at the top so I have some clearance and my threads won't come all the way up to sort of the top surface I wouldn't want to lift any material when I'm tightening screws that could interfere with the seal on the surface I know you're wondering and the answer is yes to both your questions I probably did add too many holes in now I'm paying the price and yes I'm living quite

dangerously here that's a tap Chuck in a 38 adapter in my M12 drill well then there's the parts there I say they even look respectable well at least believable you know for some guy messing around in his garage did I show you the cap part I may have not shown you the cap part same exact operations except here we've got clearance holes and counter boards screws drop in here Etc but now comes the hard part I need to flatten out the mating surfaces and sort of blend in a nice small radius that rounds its way

down into the bore can you even see what's going on in there it's a high-speed steel forming tool hopefully it won't chatter and get us a nice radius I know you're scared I'm scared too but together I think I need my magnifiers I can't totally see where the material is coming off I mean I've got a good guess holy smokes are you kidding me I don't think this tool is wrapping around enough there we [Music] go my dog doesn't like that much either I think that's pretty darn close though I bet we could blend that

out with some paper that top doesn't I mean it feels right I didn't sand out to the side so maybe it's just that like color break like from sanded to turned but yeah I'm going to call that good on the cap and that's the cap not much much happened here it was just a bit tricky to face in the four jaw Chuck since this part is thinner than like the steps and the Jaws no big deal just tedious but that's why they pay us hobby machinists the big bucks right it didn't go quite deep enough

to like 100% clean the corrosion off remember how gnarly this part looked this unfortunately is the ceiling side too but I don't know seems good enough to me on the base I did add a port for compressed air it's just a/4 inch hole it's smaller than the port in the factory knife if this doesn't work or doesn't work well I may try to open that up I'm not sure how much air something of this size is going to need I also tapped it of course so we can screw in our fitting finally we're going to

need a shim like a gasket something to set that Gap I printed a template I was going to use this to make the shim but now I got to wondering if we couldn't just use the paper itself like that this was about 2000 depending on how much I sort of squeeze with the calipers I'm measuring 3 to 4 th000 on the paper then we probably should if not account for at least mention the inkjet printing which adds probably another 40 millionths to the thickness if you plan on working in a machine shop by law at

least one in five of you will have to be the pedantic one so get your practice in when you can since there's no kill like Overkill I'm going to torque all these down to the same 30 inbs since this is a paper gasket if I just ran these in with like a little impact gun well I don't know I want to try my best to get a consistent Gap all the way around here between the two plates and I forgot where I left off I'm going to be so sad if this doesn't work oh smoke

I feel a jet of air like a ring of air how the heck am I going to hold on a minute how on [Music] Earth I got to figure something out here wait this goes I should have put a valve on the end a I was hoping that it fall through there anyway we bending the air 90° and up through that hole wonder how much this is full I don't know 90 95 PSI 100 whatever it's [Music] I am so going to regret doing this maybe we just start off with that much [Music] I've been

messing around with this thing on and off mostly off for the last couple of days honest to God I forgot just how easy I am to entertain in messing about wow look at that you see that junk in there I guess it's sawdust I must have been getting some negative pressure in here huh anyway in messing around I added a second shim to the stack I thought more air would be more better certainly that is bulletproof logic if I've never heard any turns out very much not the case with this larger gap which is I

haven't actually measured this probably around 7 thou it's the same paper print outs yeah pretty close 7th th 68 is math adds up anyway with the extra shim my air donut just didn't work all of the air immediately came out this side like maybe around like a third of the Ring I could feel like a c-shaped column of air sure I guess in hindsight that might seem obvious big gap Air's coming in here it's all going to come out this side but remember it was only 7,000 of an inch yeah I guess air will be

air I got to blow this out with some what's kind of wild is I didn't do the sawdust test with the double shims this sawdust was from before with just one shim so I guess sawdust is really thin anyway we tried one shim we tried two I mean there's really no sense in stopping now so I dug around and found this this is 2,000 of an inch so we're going closer to like the factory knife this is just some myar like plastic coated whatever Metalized that's 2000 I don't know if you can read that do

you have any idea how many bags of chips I had to eat to find this I had a little witness Mark so I'm putting this together the same way every time I don't know if that matters but give me just a second I'm going to head over to the vice and every everybody hold on your [Music] hats that feels much tighter than [Music] before I think it's making more force or at least it feels harder to push this pingpong ball back out of the hole that ought to do it I don't know if I could

really tell the difference there well you can probably already tell just by looking but I'm afraid I've got egg on my face allow me to explain the 2ow shim works way better than the 4ow don't know if you could tell over video you might have to take my word for it but the smaller shim has a much Fuller like cylindrical flow very welldeveloped like it's a much cleaner cylinder the inside feels more like Hollow I'm testing that by feel sure but there's definitely a difference I think that means we're getting better laminer flow with that

smaller Shin it's not breaking up or causing swirls or whatever might be happening but that's not the important bit my next step would be to drop down to an even thinner Shin I do have 1ou stock on hand I mean it's steel but I bet it would work or at least tell us if we're going in the right direction but before going into all that trouble I thought I'd try to do some homework which I should have done before I even started this video now that we've made it this far to something that appears to

work I got to thinking there's probably some like math model that could tell us how to optimize this specific combination of air donut like for this whole diameter this Gap this port size and air flow the room temperature and humidity phase of the moon those must be all interrelated because of course they would be and in 2 minutes of reading guess what I found that's right I reinvented the wheel I built an air amplifier I had no idea these were a thing basically we made a bladeless fan still pretty cool we managed to make one

but I don't know that Discovery just took a little bit of the wind out of my donut I don't really have a way to measure the performance of this one but get a load of this 2-in amplifier running at 90 PSI is pushing almost 400 cubic feet per minute if the spec sheet is be believed it's using about 16 cubic feet to put out 400 at the outlet at 6 in away that goes up to 1,000 cubic feet and fun fact that's with a 3ou shim I even found an adjustable one you see that nural

lock ring you loosen that adjust the Gap no shims pretty clever okay fine I guess it's not that clever but it's cool nonetheless I suppose that brings us to the end of our journey random places any to stop a video I'm still not sure why I'm so surprised this thing works I don't know maybe it's good every now and again to reassure our dominance over the physical world around us that and I can finally cross air donut off my bucket list not quite sure what I'll use this for if you have any ideas leave a

comment I could use it to make air bender jokes or maybe even welding fume EXT exraction that could be fun or you know perhaps other stuff exploration after all is the spice of life if you stuck around this long I always enjoy your company and thanks for watching