Rotational casting machine (DIY) part 2

[@LaraCroftCP]

"Hmm.. this tool is to expensive, i just will make it by my own" Exactly my style, often i think things are too expensive or badly made so i make them by my own.

[@AndysMachines]

Yes, too expensive, or the exact tool I want just doesn't even exist!

[@michaelrosenlof1084]

Very nicely done ✅👍

[@2OO_OK]

Very impressive!

[@lars-sorensen]

That is just awesome!

[@PCBWay]

This is absolutely superb, great job 👍

[@robertsorbello7288]

Sweet! You got a really good knack for precision! Excellent work!

[@almostanengineer]

I don’t know if I’m more impressed by the machine, or that mould, damn they are some nice tires.

[@thisnicklldo]

Fascinating machine, very ingenious and amazingly good result. I feel an undeserved affinity with ball chain - during the war my father (a very able engineer with whom you would have much in common) was given the task of mending a machine for making ball chain that had been in a bombed factory; apparently there were only a couple of such machines in the country, most being imported before the war, and these chains had some application as timing chains in some form of military equipment, I don't know what, not sure he ever did himself. The chain making machine was itself originally German, ironically. But I have a very vivid memory of my father, in the 60's when I was a boy, describing to me how such machines worked, fed by a coil of wire for the dumb-bells and a coil of strip for the balls. Made in a continuous process of course, a blank for the ball being stamped out of the coil into a hemispherical die, between the counterpart of which the dumb-bell wire was fed in, rapped sharply on the end to form the dumb-bell as almost simulaneously the dies closed around it forming one end of the ball, the half-dumb-bell then being sheared from the coil, another sharp rap on the other end, providing the dumb-bell end ready to accept the next ball-blank. All happening very fast and noisily. That he could reconstruct the machine with no drawings further convinced me of my fathers genius, and simultaneously revealed to me how much better his 3D spatial imagination was than mine would ever be.

[@AndysMachines]

That's very interesting, thanks for sharing! Ball chain is one of those things you just take for granted until you look at it in more detail. I found this video of an Italian machine on KZbin: kzbin.info/www/bejne/iJm9fWd5iMSfjKM It seems to work almost exactly as you describe, with a wire and strip of metal being fed in, except that it forms the dumbells in a continuous line, with each one being presumably broken off as the ball is formed around it (it's hard to see every part of the process).

[@ramizyabac3256]

@@AndysMachines Linkteki makinanın üretim yöntemi çok farklı. sizin zinciriniz zamanlama kayışı gibi çalışıyor. burada süs eşyası üretiliyor. zamanlama özelliği yok. Harika bir mühendissiniz. Paylaşımlarınız oldukça zevkli. dilinizi anlamıyorum ama ses tonunuz rahatlatıcı :) . Yabancı kanallarda sesini açtığım nadir kanalardansınız. saygılarımla.

[@grizcuz]

If KZbin/'KZbinrs' handed out awards for 'most ingenious machine'. I think this device would take first place. Everything about it, from the design to the manufacture, is just so considered and clever. At a time and in a (virtual) space where hyperbole is attached to the most mundane of things in the hunt for clicks and views. It's good to see people with genuine talent, creating something that I've never seen done before.

[@FCleff]

I've watched this twice, mouth agape both times. So much interesting stuff packed into such a short time. Thanks for sharing, Andy!

[@ethanmye-rs]

Wow, what an incredible result. Thanks for sharing the technique!

[@Smartzenegger]

It looks perfect!

[@nixie2462]

Gorgeous!

[@joell439]

I’m completely humbled. Amazing. 👍👍😎👍👍

[@CB-dx6hy]

Very impressive, nice build

[@JesseSchoch]

having that pop out of the mold must have been very very satisfying!

[@AndysMachines]

Yes, especially as I didn't show you all of the earlier failures!

[@WeCanDoThatBetter]

The tire in the end looks spectacular! I really like to see how you did the mold for this. Thanks for showing!

[@AndysMachines]

Thanks! The mould took a long time and I tried two other methods to make it before deciding the only way was to machine the whole thing in sections. I still might do it differently next time though.

[@WeCanDoThatBetter]

@@AndysMachines Thanks for your reply! Sounds really interesting. A video on mould making would be great :)

[@julias-shed]

Neat. There’s some work in that mould. Can you do a video on that? 😀

[@almostanengineer]

I’d love to see a video on that too.

[@smithe53]

Same here!

[@AndysMachines]

You are right! There was some work involved in that! I actually tried 2 other methods to make this mould (casting and electro-forming) before realising that the only way was to machine the whole thing in sections (I knew this from the start, but also knew it would be the most time-consuming way, so tried to save some time, but the results were not good). I did get some footage of the process but not enough to make a whole video just about this. If I ever do a video series on what these tyres are for then I'll include it in that.

[@anotherguy9402]

@@AndysMachines isn't it funny how we always try to save time but end up spending twice as much if not more on our "shortcuts"

[@AndysMachines]

@@anotherguy9402 Thats true! "Do it right, do it once"

[@anmolsingh4664]

Woah nice video, also make more videos of gears👍

[@bowieinc]

Really enjoyed the video. My favorite part was actually learning how the ball chain links attach:)

[@AndysMachines]

Yes, it's one of those things you see all the time but never give much thought to!

[@antonio.stefanelli]

Fantastic

[@OMGWTFBBQSHEEP]

Wow. That result blew my mind. And the machine is so cleverly built!

[@jdmccorful]

Freakin "Impressive" ! Enjoyed watching the 3 videos you have on this machine. Thanks!!!

[@petermines3575]

Awesome.

[@gafrers]

Great. 👍👍

[@bambuskat]

Cool little machine you got there. I work at a rotational molding company. Our standard speed is Arm = 7 rpm Plate = 2.8 rpm And it reverses every 1.5 minute. We cast PE/PP powder And liquid pvc parts. And just recently started molding in PA12 nylon.

[@AndysMachines]

Thanks for the information. I determined by trial and error that around 7-8 rpm seems to work best (I initially thought much slower would be better). Somebody else mentioned reversing the direction and also that 2:1 works better for symmetrical moulds than 4:1, At 7/2.8 rpm you are running a 2.5:1 ratio. For my next batch I will try reducing the ratio as I can do this easily by changing the large pulley for a smaller one.

[@narada4421]

@@AndysMachines how did this go? im trying to cast hollow silicone balls but it ain't easy. initial results with 1:4 gear ratio are mixed. i got one ball with good coverage at the top/bottom but the silicone that was supposed to cover the front/right/back/left just formed a blob which sits in the middle.. 1:4 made sense in theory but in practice is seems like a good idea to go back to 1:2 again. also; how do you determine the speed? just trial and error? i made transparent molds as i figured it would be useful to bump up the speed so that the liquid silicone would barely stay level. thanks for the video and information, it really inspired me to make a rotocaster above the triple frame designs!

[@AndysMachines]

I determined the speed by trial and error. Initially I thought faster would be better, but it's not. Since I used up the last of my resin I've not needed to rotocast any more parts, but I would like to get back to this and try the 1:2 ratio to see how that compares. If you have a big blob forming you may be going too fast, try going much slower than you think you need and see if that helps.

[@KallePihlajasaari]

@@narada4421 My intuition is to have the ratio a quotient of two primes so that the puddle of liquid material takes a different path each time. Think of Lissajous patters, with 1:2 or 1:4 ratio forms a static image and of just a few lines, with a funny fraction the area is filled Having a ratio of 13:37 or similar might provide a start and having slight slip with a smooth drive belt might not matter at all in the end.

[@homemadetools]

Great work yet again. We shared this video on our homemade tools forum this week 😎

[@jimsvideos7201]

The project, the video and the results are all top-notch; thank you indeed for sharing!

[@AtlasF0und69]

A tip for specialty tools you'll only use once; buy it from somewhere with a good return policy lol. Great vid, keep up the good work!

[@gregwmanning]

Amazing ... again

[@AndysMachines]

Thanks!

[@Falconguygaming]

Outstanding job, cool machine

[@e2jw]

Wow! Fantastic job with this and great results! Thanks very much for posting these!

[@EverydayJourney]

Awesome

[@ruftime]

Just too cool as always Andy! So exciting to see such a beautiful RC tire……love to see what it goes on. I’m loving 1/10 Comp Crawling and cutting custom foams on my CO2 laser. Greetings from SoCal 😎

[@learningturningmetal]

Fantastic result and some great tips along the way 👍 Cheers Andrew

[@anzormachineryseal2743]

GOOG

[@anzormachineryseal2743]

Your work is excellent video

[@anuarabdulsamad2688]

always a pleasure watching your video...... 👍

[@Tarbard]

So good. This would also make an excellent fairground ride for a gerbil.

[@noviceartisan]

Incredible work as always dude! Thanks for sharing your marvellous machine creations! xD

[@boanderson5057]

You are absolutely incredible!

[@wizrom3046]

Great project. I suggest a spray on mould release.

[@Smallathe]

Very impressive machine design and build!

[@bradley3549]

For the hole without a holesaw - that would have been a good use case for a trepanning tool in the boring bar holder. Even factoring the time to grind the tool, you would have probably saved time overall on the two holes.

[@AndysMachines]

I've never actually tried trepanning with my boring head, but yes that's another good way it could be done. I'll make a tool like that one day!

[@aldobruno712]

that's some awesome job Andy, I loved the video, congrats! Would you please make a video and give information about the tire mold you have at 13:50 ? Was it made with CNC and would you show the build process, if it is selfmade? Also another thing, I am completely ignorant about resin, that's an idea for a future video of yours showcasing how they work !

[@Smartzenegger]

Simply amazing once again. You're a true scientist. :)

[@ChristophLehner]

Came.out really nice 👌

[@pepzi_]

Watching this for the second time around 1 year apart. Amazing work! Since I'm learning Solidworks this time watching, I'll challenge myself and make the parts and assembly in 3d :) Might even give me a chance to try the simulator aspect of Solidworks!

[@goowatch]

Great gyroscopic implementation. Thanks for share your experience.

[@mandrakejake]

Nice tool. I'm wonder if there's a direct correlation between viscosity and correct mould rotation speed? Perhaps a drop test on a slope with correct gradients for RPM would help set it up

[@JaenEngineering]

I'd say it's definitely worth investigating. Also, would it be worth ramping the speed (up or down) as the compound being cast begins to set and it's viscosity changes.

[@AndysMachines]

@@JaenEngineering Yes, you would image there would be a correlation, but many things about this process seem counter-intuitive. I tried two different resins with different viscosities and found they both worked best at the same speed. It seems to be better to go too fast than too slow.

[@mackdaddy.7610]

I made a centrifuge casting machine in 2005 made from a bicycle wheel bolted to a sheet of plywood for casting my jewelry.

[@m.s.idrischannel5655]

wow, very nice video. I have done it but failed to get a very smooth results. what kind of speed this you use?

[@AndysMachines]

I also got thick and thin spots, not enough to be a big problem, but could be more even. I think changing the ratio from 4:1 to 2:1 might help but I haven't tired that yet. I got best results around 6-7rpm I think.

[@nou5440]

nice

[@JAAKLAB]

great job, what kind of rubber did you cast please?

[@AndysMachines]

Thanks, It was a 2 part polyurethane rubber, I tried 2 different ones made by Polytek and Polycraft.

[@JAAKLAB]

@@AndysMachines thanks so much , did you noticed a difference between the 2 products?

[@AndysMachines]

@@JAAKLAB Yes, different viscosities, different setting times, different rubber hardness. Still not sure which one is best though.

[@JAAKLAB]

@@AndysMachines many thanks

[@jeffkthompson]

Would love to see a video on how you made those custom buttons too!

[@AndysMachines]

They are 3D printed, the symbols filled with paint, then the tops sanded smooth. You can see the whole process in one of my other videos: kzbin.info/www/bejne/mJa3aWZnZ9Bmr6s I've used this technique on a few of my machines, it's quick and easy and looks professional.

[@jeffkthompson]

@@AndysMachines thanks! They look so much better than most 3D printed ones I've seen, I figured they were cast or something!

[@en2oh]

I have a feeling that that phrase "good enough" is not used very often, in your shop! Seriously though, have you done anything on mold making? Specifically, how you made (assuming you made it, of course!) the break-a-way tire old. The tread detail, the indicia on the side walls. Thanks for sharing your work with us!

[@AndysMachines]

I haven't really covered mould making, though I may have touched on it in other videos where I had to make a mould for something. I did make this tyre mould and it took me 3 attempts, each by a different method, until it was "good enough"!

[@antonwinter630]

thats a great tool. do you have a video on making the tire mold?

[@marknahabedian1803]

Neat project. I was wondering if you could get away with using string instead of ball chain though. I guess it would depend on how much torque it takes to swing the resin (the mold can be balanced before filled). A cord and pulley transmission works fine on a spinning wheel, where one is amplifying rotational speed rather than torque. I'd think that your application doesn't require a precise ratio, so a small amount of slip could be tolerated. Could you estimate how much rotational speed is needed by measuring the flow rate of the resin? I wonder if measuring the motor current is accurate enough to guestimate where the resin is inside the mold?

[@AndysMachines]

Thanks! Yes you could use string, or better round rubber belt (comes in long lengths and is easily joined to make any size belt) but as you say it wouldn't be synchronous which isn't so important but it would be much more likely to slip than a toothed chain or belt so would need to be run with higher tension. One nice thing about it being synchronous it that you can stop it with the mould dead horizontal every time which makes filling it much easier, if there were any slip it would no longer be horizontal in both planes at any point so you'd have to make do getting it as level possible or adjusting it by removing the belt. As for getting the correct rotational speed, this seems to be non-intuitive and needs a bit of trial and error. The current measuring is an interesting idea though!

[@K1VV1939]

Is that piece of square tube a piece of roadworks sign stand? - the bit with the yellow on. In your workshop do you use a lot of alli 3.5mm plate, 25mm square and the 35mm od square at all - like in projects? Road works signs - Awesome just saying

[@AndysMachines]

That tube was a piece of scrap from an older project, a piece of 60 x 60 box section I bought a length of years ago. I actually do have some 3mm ali sheets that were originally road signs, but the metal is very soft and gummy, I think it's nearly pure aluminium, not very nice to work with and the reflective vinyl that is stuck to them is very hard to remove. About the only thing I used them for was when I hammered a terminator skull out of flat sheet (check my other videos) since it can be formed without becoming too brittle.

[@K1VV1939]

@@AndysMachines Hell no Andy I was alerted to the Humble Road sign by someone who had just reskinned his Home Bus in 600 x 600 square sections - it looks awesome - and all the hard to remove stuff was inside the bodywork - kinda isolation at 50/70/100km Love you man

[@R.Daneel]

I'm curious - could you carve the drive gear as if the whole chain were made of those connector links? Once aligned, wouldn't it just work the same? Each "tooth" would hold two of the beads instead of one _and_ accommodate the connector link. In my head it works. Not sure about real life. The only gotcha would be making sure an even number of beads on the whole chain so the connection link always lands appropriately aligned, and not across two holes.

[@AndysMachines]

Yes, I could have done that by removing every other tooth on the pulleys, however it would only work with an even number of teeth on both pulleys and an even number of links on the chain. The small pulley has 13 teeth. Also the connector link is not exactly 2 beads in length, more like 2.5, but I probably could have adjusted it or made a shorter one.

[@bilplaymo6121]

Result is beautiful ( explained by metal mould ? ) beautiful tyres, is it 1/6 scale ? that's why these machine have future : sometimes impossible to find the correct items ( scale/ material/ qty.. ) in this case...a tyre...take care, cheers : )

[@AndysMachines]

Thanks! These are actually 1/8th scale commercial truck tyres, you can find model tyres this size but the options are very limited (and they're expensive). Besides, I just wanted to make my own.

[@bilplaymo6121]

@@AndysMachines you've rigth Andy, when no exist do it yourself...1/8 is not enought, it's really 1/6 that I want...many, many thanks for all your movie on Utube, it's inspirating ! take care : )

[@perspectivex]

I wonder if you could have left the bigger locking link in place rather than build the tool to join the dumbbells by cutting a single special indent in the pulleys for it...assuming that the ratios of the pulleys and chain length could be adjusted so that the big link would always fall into those special slots, and assuming the chain never slips.

[@AndysMachines]

I did think of doing something like this (removing every other tooth). However the small pulley has an odd number of teeth, so this wouldn't have worked, but with an even number on both pulleys and an even number of beads on the chain it would. I expect the chain would break before it ever slipped

[@thecorbies]

Hi Andy, excellent video as always. I don't know what kind of PU rubber you used, but if you have control over the curing time that would help an even distribution with in the mould I'm sure. I say this as someone who would like to make large scale tyres but don't really want to/cannot justify for such limited use, the lengths that you have gone to achieve it. As others have have mentioned, I also would love to see the production of the tyre mould too. Regards Mark in the UK

[@AndysMachines]

Thanks! I tried two different types of rubber with working times of ~10 minutes and ~ 2 hours. I thought the longer curing time would be easier to work with, but actually found the opposite. There is an effect known as 'flash curing' where if you have a large pool of resin rolling around inside the mould, this tends to set first and form a large lump. Also I thought slow speeds would coat the mould more evenly, but found faster was better. It doesn't seem very intuitive and I'm learning as I go. The viscosity of resins can also vary a lot, which is another factor to deal with.

[@leonmotter]

@@AndysMachines Let me first say i design and build proffesional rotational mould machines (for plastics like LLDPE and PP), and i am impressed with what you have made. I can confirm that the higher speed should be the best. the most standard setting is 8:4 (8 rpm for the arm and 4 rpm for the form). When your moulds get more assymetrical 8:2 might work better. Unfortunately you can not change that. Maybe an upgrade for the future. Another thing that can help with assymetrical or complex moulds is to change direction during casting. We do it around each 2 mins (in a 10 min cycle). so in your case it would probably be a little quicker. I hope this information helps a bit and looking forward to more videos.

[@AndysMachines]

@@leonmotter Thanks for the information, that's very interesting! I had found by trial and error that a ratio close to 8:2 rpm seems to work best, but I still get thicker and thinner spots in some areas. Maybe 8:4 would work better. No, I can't vary the ratio of the machine, but I could easily make a smaller pulley for the form so it has a fixed ratio of 2:1 instead of 4:1. It also currently only runs in one direction but it wouldn't be too much work to make it alternate direction. I might experiment with both of these and see what difference it makes. 👍

[@leonmotter]

@@AndysMachines In conventional rotomoulding aka heating the mould from the outside to melt plastic, thin and thick spots are created by having either hot or cold spots, material builds up more where it is hotter. In your case it can only be controlled by your rotational speeds of the arm and form. But keep in mind that the amount of material versus free space in the mould matters. i would also try to decrease the amount of material you use and see if that gets a better result. It is a problem we always face with products with a really smal internal volume.

[@steveh9169]

same principle as we used at red tulip chocolates to mould easter eggs.....

[@PSimonsen]

How did you make the mold for the tire ? Looks like EDM

[@AndysMachines]

I tried several methods unsuccessfully (including EDM/ECM) before I just machined the whole thing in sections.

[@slypig24]

A fantastic build, you tyre mold looked very instresting, did you make it? Cheers from Australia 🇦🇺 🦘

[@d00dEEE]

I was waiting for the gopro-view mounted on the faceplate, make us completely seasick!

[@BrlU]

Nice!!

[@mricad939]

I want to know more about this project

[@gerardbeattie4139]

Very interesting design . I am interested in the motor controller , is there another video on building the motor controller?As your design Has given me an idea on building a tube casting machine, are you to willing to share the design and building of the motor controller?

[@AndysMachines]

The controller is very similar to other ones I've shown on my channel in more detail. I didn't go into it further as it's very specific to this machine and it's unlikely anybody else will build an exactly identical machine even if they base it on my design. The controller is built from an Atmega328 MCU and an OLED display, there is a home-made optical encoder that measures the speed, the output is just a selectable PWM signal, there is no PID loop or anything to maintain the speed, the gear reduction and fact that the mass is fairly well balanced keeps the speed constant.

[@christianfilloux]

What size bead chain did you use? Im using smaller bead chain for a small Z axis table and they stretch over time so much!!!! its crazy. maybe i need to pre stretch it? or heat then quench?

[@AndysMachines]

4.5mm. I haven't noticed any stretch after many tens of hours run time, but it's only under light load and I can take up any slack easily with a turn of a screw. Bead chain is available in larger sizes (up to at least 16mm!), but I would expect some stretch under heavy load, even regular roller chain stretches over time (the 'stretch' is actually due to wear in the pins)

[@ariesmars29]

Very cool! Looks like a professionally made tire. What is that tool at 7:31? I need one of those for my mini mill. The name escapes me at the moment.

[@AndysMachines]

That's a boring head. Very useful tool, turns a mill into a lathe for parts that are too big to swing in a lathe.

[@narada4421]

Hi, I made a machine based on yours! I love the belted approach. Can you tell me more about the motor setup you got there? I have a smaller and lighter machine, and tried to use a stepper since I need to test various RPM's (and i know how to control steppers and not much else..) but it is not strong enough. I can get a bigger stepper, which needs a better driver, but I want to make a dozen of these machines for a small production run and in that scenario the price is considerable. One last note; due to my material choice I need quite high RMPs (around 100) since I will use the centripetal force in my advantage. So basically I need something cheap and strong which can be adjusted in regards of RMP. I would love to hear you insights!

[@AndysMachines]

Look for used car windshield wiper motors, these are cheap, powerful and have a built in gearbox that give about the speed you need. But even with a small stepper motor you should be able to gear it down enough to give the torque you need, adding a counterweight to balance the mould will help.

[@peteredwards2371]

You clever man 👍❤️

[@PatrickPease]

What would happen if it cycled through the entire range of speeds such that it always spent some time at the optimal speed following the principle that "even a broken clock is correct 2x daily"

[@AndysMachines]

It's an idea, but it would spend over 90% of the time going at the wrong speed. As I understand it the goal is to avoid a large puddle of resin pooling in one spot, the resin generates heat as it cures which speeds up the curing and can cause lumps to form where the resin pools. Some people have suggested reversing the direction periodically can help, but mainly for less symmetrical moulds.

[@johnnym1320]

I'm sure you've been this asked before but why not use a timing belt instead of a bead chain?

[@AndysMachines]

Because a (flat) belt would have to twist 90° around the corner, which is possible, some car engines even do that, but bead chain can just bend in any direction and I liked that solution better. A round belt would also work but it wouldn't be synchronous.

[@JohnJones-oy3md]

4:45 - Who else was expecting him to carefully tig weld the seams on each and every one of these spheres? LOL

[@kezyka6775]

Great stuff :)

[@Toannghiacokhi1]

New subscriber

[@JustinAlexanderBell]

Neat

[@IrenESorius]

Hmmm,, how did you do the threadpattern in the mold? (Is it called "threadpattern"? The part of the tyre that hits the asphalt.) Very impressive video as always Andy. Thanks for your time and work. Cheers,, 🍻🙂👍‍‍

[@douro20]

I figured this would be for a cold casting process, but then the synthesis of PUs is not exactly a cold process as the polymerisation of isocyanates is exothermic.

[@MyLilMule]

Nicely done. I'm not into this particular hobby of mold making and casting, but this looks like a machine for which there could be some commercial demand, do you think?

[@AndysMachines]

You can actually buy small rotocasting machines for hobby use, however they seem expensive for what they are, not much different to many home-made ones you can see on KZbin and the idea is quite simple and probably not hard to build for the type of person who would have a use for one.

[@Simple_Technology_]

Крутой результат!

[@originalmianos]

Did I miss the reason why he didn't just use a second stepper for the secondary rotor?

[@AndysMachines]

That would have been more complicated to build. But it would give the option of being able to vary the ratio on demand.

[@originalmianos]

@@AndysMachines A slip ring would be a little tricky, not much else more so.

[@perspectivex]

@@AndysMachines I was going to ask the same question... it'd eliminate that ton of work you did milling pulleys, making the idler, and making the ball crimper etc. It seems like it'd be way simpler.

[@K1VV1939]

What country Andy

[@AndysMachines]

I'm in the UK, only our permanent highway signs seem to be made from aluminium sheet here. Roadworks signs are thin steel or plastic usually on flimsy fold-up angle iron stands, they have to be weighed down with sand bags to stop them blowing away.

[@MG-xm3yv]

I bet your tired after all of that 😂 😂 Great continental (content) sorry i wheel stop with comments I’ll get a grip after over inflating my comment, I feel a bit deflated now Thanks mate awesome

[@Ayce47]

Why not add a buzzer to know when it's finished?

[@AndysMachines]

That would be simple to do, but I tend to just leave it running while I go away and do something else, then come back later when it's finished.

[@Heisenberg2097]

Please build it maybe 20-30 times bigger... mount a seat... and make it faster... THEN I WILL ENJOY THE RIDE!!! Great video and good details!

[@perspectivex]

Maybe you'd enjoy this kzbin.info/www/bejne/eaCkXqBrnq16b9U

[@AndysMachines]

@@perspectivex That exact thing popped into my mind when I read Chris' comment above!

[@Toannghiacokhi1]

Thích 👍 và đăng ký kêh

[@ImpactWench]

It would probably have been OK to mill the cogs as if the chain consisted of only splicing connectors. Would have limited the chain to an even length and you would have had to go to a 14/56 cog pair, but you would have saved yourself the manufacturing of the pliers.

[@AndysMachines]

True. Other people suggested that too but failed to realise that both the chain and pulleys would all have to have an even number of teeth/links. The way I did it was more work, but it just seems better to me (if only marginally) and gives more flexibility, eg. I can change the ratio by just changing a pulley and shorten/lengthen the chain without having to keep track of the number of links (yes I could just use trial and error and cut off one more ball if it was an odd number). Somebody suggested it might work better with a 2:1 ratio instead of 4:1 and I've been toying with the idea of 3D printing a new pulley to see how that compares to a machined one.

[@NitroTom91]

Why did you go through the trouble with using a chain like that? It seems to me that the exact rotation is rather uncritical, so a normal flat belt would have been my choice to save a lot of time. In the end it's your machine :) Great work as always!

[@AndysMachines]

I just think the chain is a slightly more elegant solution than a twisted flat belt, but either would work. There are examples on KZbin of people using a twisted toothed belt for this and it looks like it works fine even though it might look a bit odd to use the belt this way. The load and speed are very low so the twisting doesn't really affect the belt. The design of the machine is almost the same so the only extra work involved was in making the chain into a loop. The machine doesn't have to be perfectly synchronous, though it is nice to be able to stop it with the mould horizontally level for filling with resin. Even a round rubber belt with non-toothed pulleys will probably work fine.

[@ametistihiomo]

What a cool, imaginative DIY project. But as a rotomoulder, 2nd generation in family, we've been doing this for well over 40 years, I must object to calling it "rotational casting". If there really is a country or a group that calls it that, please let me know?

[@AndysMachines]

Well, I really don't have a lot of experience with casting resins, I'm learning as I go. Though I have also done some injection moulding. But as I understand it, rotomoulding is a thermoplastic process where the mould usually spins inside an oven? I'm in the UK by the way, not sure if that makes a difference to what it's called.

[@ametistihiomo]

​@@AndysMachines Please excuse me, as I am not a native english speaker. I meant my comment as lighthearted nitpicking. The way I have been taught on these terms is you cast metals and mould plastics. I may be way off, and who cares, the point is I love the project and please keep on doing such fun projects.

[@ObviousSchism]

So many tires.

[@eulerizeit]

You didn't cast a duck. All the duck pictures and no duck.

[@AndysMachines]

Sorry! Maybe next time.

[@eulerizeit]

@@AndysMachines THis was an awesome video. thanks.

[@djdarthzman]

good tools but so advance. I can't do this.

[@MACTEPCKA9I_HA_MUHUMAJIKAX]

классно, но долго.

[@AnthonyHandcock]

No yellow rubber duck?

[@AndysMachines]

Sorry! 😟🐥

[@AnthonyHandcock]

@@AndysMachines Sorry... I was being a bit grumpy and I'm sure it will be in an upcoming episode. I'm just going to pretend you've promised it as a Christmas special as they are so Christmassy... No... Seriously... Every time I've bought an adult friend a yellow rubber duck for xmas they've loved it... Or they were just being polite and humouring me... Definitely one of the two.