Homemade Rotary Disc Valve And Spool Valves For The Steam Engine (I’ve been busy!)

There are lots of mistakes in this video - at least now you don’t need to make them too. Don’t bother making a rotary disc valve unless you have a way of polishing the surfaces perfectly. Sadly they seem to be too difficult to make. And the spool valves - although simple - weren’t that easy either. Who would have thought it was so tricky to get moving things airtight. But we got there in the end - sort of : - )
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[@ciarantaylor367]

It is so comforting to see someone else go through all the options that don't work before finding a solution. It hurts when I feel like it's just me who does this. Tim's combination of optimism, humour and persistence are such a joy to watch!

[@PKMartin]

Everyone who makes things has this feeling - if everything you try works first time you're not trying hard enough things! Some KZbin channels just skip to the working version and some (the honest ones!) show their "ones that didn't work" as well

[@dieSpinnt]

Just some trivia and side notes: The Antikythera mechanism is an ancient device comparable to an astronomical clock that used gears and dials to show astronomical and calendar relationships. It was discovered in 1900 by sponge divers along with other finds, including bronze statues and coins, in a shipwreck off the Greek island of Antikythera. The coins allowed the shipwreck to be dated to the period between 70 and 60 BC. The use of reamers (comparable to watchmaking hand-tools today) is clearly documented in this artifact. That's fascinating, isn't it?:) For even greater precision, such as that which you are looking for for your airtight metal fit, there is the option of grinding. And believe it or not, this was also used over 2000 years ago. For example, with adapted soapstone and a flywheel with a twisted thread hand drive. Great project and thank you for sharing!:)))

[@CPWorld68]

You need a counter weight on the main fly wheel to take it over the end of the compression stroke ..

[@schwuzi]

Maybe he'll try to build a version that works on both strokes. A counterweight would also generate a lot of imbalance and vibration once it gets up to speed.

[@mattbraysails]

And drag on power stroke. Need 2 or 3 engines.

[@CPWorld68]

Back to the drawing board....

[@gruenerKoenig]

I like the process very much, it is like the history of inventing the steam engine taking place right in your workshop. It looks promising and on a very good way!

[@chalichaligha3234]

Early steam engines used "D" slide valves Tim! They seal really well and are found all over the heritage steam world today. The valve works by being a cup over the exhaust port, connecting it to the cylinder port at the right time, and clearing the cylinder port to allow the steam in. The seal is simple because the cup is being forced onto the port plate by steam pressure. The seal between the valve rod and the valve body is typically done using gland packing. You could certainly apply the same concept to your rotary valve to make it seal properly! The reason this was a nearly unheard of arrangement during the age of steam is because for maximum efficiency you want to put the valve as close as possible to the cylinders so that the vapour follows the least tortuous path to and from it's work shift as it were. But also because it's a lot easier to put a reciprocating valve in "reverse" and varying degrees of cutoff using valve gear than with a rotary valve. Good luck with the project Tim! I love seeing where your tinkering takes you :)

[@wayoutwest-workshopstuff6299]

Thanks, Chali. I have so much to learn, but gland packing makes a lot more sense to me than it would have done a month ago : - )

[@davidtaylor6124]

Yes, assuming you have a milling machine, slide valves are a much easier option.

[@chalichaligha3234]

@@davidtaylor6124 How about by layering two pieces of plate, one with a cutout, and welding/screwing them together?

[@chalichaligha3234]

@@wayoutwest-workshopstuff6299 : - )

[@johnalexander4356]

Have a look at David Richard's KZbin channel. He knows more about steam engines, fixing them, designing them, and building them than anyone else that is still working. And he is a good teacher. He operates a steam engine powered, line-shaft machine shop. He shows his viewers way more than you'll find elsewhere. Good luck!

[@BrassLock]

It's making all the right noises, so it must be a winner! An uplifting story for these woeful times in the "modern, civilised" world.

[@weird1012]

7:30 this is genuinely great content

[@Hidegety1]

This all is so cool. Goal, ideas, prototyping, failing, correcting, re-prototyping, succeeding, failing somewhere else... Seeing this contraption being spawned is a fascinating process. Like a machine form Jules Verne book.

[@TheMrWoodsman]

After over 40 years in CNc engineering, you are way above me, how to time such a wonderful thing is very difficult.

[@pvtimberfaller]

So what you need to do is simply make the steam groove in the valve longer and drill a second hole for exhaust, you don’t need two valves for a single acting engine. With that modification you can have a double acting engine. I wish I was you neighbor, I could help you out on this project! Maybe trade an Airedale puppy for machine work.😄

[@jamesmisener3006]

Tim is reinventing the wheel and I think it's going to be a beautiful wheel. Cheers 🇨🇦

[@metalmicky]

Heath Robinson is alive and well !! Innovation at its diy finest. More please.

[@nathanlucas6465]

The last valves shown make such a satisfying noise

[@TheCastleMarch]

You should have a world record in future for “worlds only 1ft gauge homemade train”

[@benfitch8795]

Excellent work! To seal the valves traction engines use glands. They have a grease soaked rope inside a cavity around the rod and it's squeezed by a gland nut.

[@wayoutwest-workshopstuff6299]

Thanks Ben. That's very interesting and helpful

[@peterjensen6233]

Beautiful design Tim. I know you have fixed this and moved on to the next one. But here it goes anyway. If each cam were made up of two discs. One has a ramp up an the other a ramp down. You could adjust the open time by rotating them. Just a thought. Good luck!

[@wayoutwest-workshopstuff6299]

I like it!

[@felderup]

the rotary plate valve is really common in those weird toy steam engines, specially the ones from the 60's. a while back i figured out a pseudo super high pressure pump that used almost the same design, you could add one easily. the trick with them is to put pressure on one side and the exhaust on the other, so the steam pressure holds the valve tightly closed.

[@clutchkicker392ison5]

Im a petrol man at heart but this was entertaining enough to watch till the end , cheers and good luck.

[@BlackheartCharlie]

I think the cam/spool valve mechanism is much more interesting to watch than the rotary disc valve. :-)

[@jetownsend1]

If I had the money, I would buy you a mill and lathe, just to see what you could do with it. If you are this ingenious with fairly basic tools, I can only imagine what you could make with a real machine shop.

[@IrenESorius]

A tip for the future, in all friendliness. The steam inlet inlet should be ca 30% of the power stroke to let the steam expand. Cheers,, 🍻😎👍‍‍.

[@wayoutwest-workshopstuff6299]

Thanks, Irene. Yes, that's helpful to know

[@NicoSmets]

All the problems you encountered were fairly predictable (as you know yourself too), but it's very admirable that you tried them anyawy.

[@BadgerBishop]

The first steam engines used packing to create seals I'd think. The first idea would have been a beautiful execution, it need a lot of precision flattening though. I believe Ox Tools did a video with a couple metal discs and a bunch of pennies glued to it to demonstrate principles of flattening. The second idea worked out in the end, after the first failure I said to myself, "he needs to use annundersized drill bit then a reamer". I don't blame you for getting it wrong, I wouldn't have had the right tool laying around. I only know things because I enjoy watching machinists to unwind. The final idea turned out beautifully, I want one as is so I can listen to it run, the sound it makes just seems right.

[@wayoutwest-workshopstuff6299]

Thanks, Joseph : - )

[@lv_woodturner3899]

Consider machining some grooves for O rings on the spool valve shaft on Wills metal lathe. This will reduce air leaks. I think the old machines honed the cylinder to dimension and machined the spool valve shaft to be a tighter fit. Reamers are more accurate than drills as you observed, but when I need a tolerance fit, I use a boring bar to sneak up on the dimension. Well done. Terrific progress. Dave.

[@bootsowen]

I thought that too, but would o rings take steam? Steam oil maybe?

[@lv_woodturner3899]

I expect if he needed a solution for steam, then some kind of piston ring would be needed. Vintage machines would make these out of cast iron. I have seen several video on making cast iron piston rings. Not easy, but possible. Dave.

[@jameshodgson1609]

I was thinking O rings would allow you to get away with less worries about tolerance and have the advantage that they work well both hot and cold. Keith Appleton has done some recent videos on making new piston rods with o rings . These will work well with saturated steam at least. I love the laser cut cams and the ease you can cut another one to modify the valve timing.

[@johnnytarponds9292]

Fantastic design! Despite your self deprecating humour, your mechanicals are beautiful to see in operation. Excellent work.

[@frankfreeman1444]

With a metal lathe you can cut 2 internal grooves and put o-rings in them to seal the spool to the cylinder.

[@tropifiori]

My air hammer has a proprietary spool valve. The inner shaft has o rings on each side of the narrowed spindle. Your design is very elegant. I love the way you trouble shoot. Frank

[@wayoutwest-workshopstuff6299]

Thanks, frank : - )

[@saulsgamingchannel9596]

Heres some tips if your building a steam engine, I've known a lot of steam locomotives, Though Narrow gauge steam engines are a bit tricky, some have small coal bunkers And are only useful for small distances, The Solution to this is a tender, This also makes problems, The first one of which is the water injector, These may fail sometimes and without a water injector and tender engine simply can't function, I Would suggest to build an engine with a water tank that can store more than 15 gallons, Make the engine with a built-in tender for storing more charcoal or any type of fuel your using, Problems with the firebox are also common, make sure your engine has a large firebox or you can build it a small one and use welsh coal which burns better, The reason i suggest this is beacuse this is what ive know so far, Oh and if your building an Passanger engine, Add an front pony truck [bassically an truck thats connected to one end of the locomotive and makes it easier for it to go through curves] Of course this will be expensive but it might be worth it, Also you may end up creating a incredible fully runing railway.

[@wayoutwest-workshopstuff6299]

Thanks, Saul. But it'll be a long time before I need worry about any of that : - )

[@ronbach6453]

This is why O-rings are used to seal the pistons. They seal the chamber where the air/steam is as the piston moves back and forth, not letting it escape.

[@wayoutwest-workshopstuff6299]

But O rings for steam? Can they cope with the heat?

[@ronbach6453]

@@wayoutwest-workshopstuff6299 You can get ones that will work depending on the temp, your best bet is to get a catalogue from a supplier/visit rheir website.

[@ronbach6453]

@@wayoutwest-workshopstuff6299 Silicon will handle heat up to 250C, here is a video about O-Rings kzbin.info/www/bejne/l6jIdYqrg9CDrZI

[@nquinn91]

Sorry to hear about your expensive week, I hope making some progress makes up for it a little

[@JonatanGronoset]

Every steam engine piston and valve rod has stuffing glands with a packing material like graphited yarn that acts as a seal. You screw in the gland (not too much!) and the packing squeezes around the rod to seal it. It works on air too.

[@wayoutwest-workshopstuff6299]

Yes, thanks, I've just heard about this. So much to learn!

[@ddd3240]

Worked on reciprocating steam pumps for many years in the oil industry. Nearly all were two cylinder. The single cylinder pumps were nearly always a pain to time correctly and get to run correctly. 99% of the two cylinder steam pumps had slide plate valves that were connected to the piston rods by an arm that fit loosely on the piston rod. Much simpler than I can describe. The single cylinder pumps had a slide piston valve like you were trying to assemble. I hated the silly things. Good luck.

[@robinforrest7680]

How did I miss this? Must’ve been a busy week! Thanks Tim as always 👍

[@hetrodoxly1203]

Great stuff, a 3-way pneumatic valve can be purchased for around £10, but not nearly half as much fun, engineers of the past didn't run steel on steel, you can run steel on cast without binding, but it wouldn't hold air, they used gaskets and seals, you can get steel on steel valves bet these are case hardened then precision ground to size, usually tapering but not always.

[@jenhofmann]

Every attempt that ends in "failure" provides more insight into what *will* work! Bravo, sir! I'm celebrating with you from the other side of the world!

[@thetransformatorium7980]

I love watching you go from failure to failure with no apparent loss of enthusiasm! I wish I lived closer, so we could team up on these sorts of projects, but I'm in the us so that would not be terribly practical. I've built a small steam engine out of an automotive air conditioning compressor utilizing rotary valves which runs well on air, but I don't plan on running it on water steam. I'll be using a refrigerant as the working fluid, so it will be a completely sealed condensing steam engine. As soon as I get the boiler feed pump to work, I'll be posting more videos about it. Cheers M8!

[@wayoutwest-workshopstuff6299]

Excellent! Good luck.

[@boelwerkr]

You can grind the plates to a match. But the distance between the covering plates have to be adjustable. Rotate the valve plate with a drill between the covering plates. put a weight on the upper covering plate (ideally the weight is distributes equally) Put a clay slurry on the contact faces and run the drill. In intervals tum the plates in relation to each other to equal out inconstant pressure distribution and add slurry. I made a seal for pressure pot this way. Took me only two days. :-) Clay slurry is a surprisingly good lapping medium. (It probably depends on the region :-) )

[@wayoutwest-workshopstuff6299]

Ha! You know you can buy carborundum paste, which might make it quicker?

[@neffk]

Lots of early mechanic work was making parts FIT each other by lots of trials, lapping, and other tricks. So each assembly was unique. But your point about the difficulty of this project is a good one. Drilling an accurate deep round hole is a difficult task. There's more than meets the eye.

[@kulebyakinjoe]

Ingenious and simple gas distribution mechanism

[@kyrathorsinclaire]

It's great to see you working on this, and other things, working through various plans and options, and eventually figuring things out. It's entertaining, and informative, watching you create your contraptions.

[@gii_vannile]

Thank you very much . Try and error and examining and try again . Never easily giving up . Mar. 17th 2022 Thu. 07:53 am from Yokohama City Japan

[@mungmungie]

Your inventiveness never fails to surprise, entertain, and amze. Certainly leaves me wondering how steam engineers made the things they did a century and a half ago.

[@wayoutwest-workshopstuff6299]

Thanks Peter. Yep, exactly.

[@Nilguiri]

It's a lovely, simple yet ingenious design which is extremely satisfying to watch and listen to. Just a little bit more tweaking left!

[@FreezerBurn.]

Before you know it you’ll have an engine that will take you to the moon and back! Great progress. Stay safe!

[@mickys8065]

just hearing the 2 camshafts go before you added air was already so pleasing! Truly a great sound. My personal theory is that the original steam users went with a more brute force approach, where they used enough pressure that any steam loss was comparatively little.

[@vintagestuffguy1998]

This is extremely cool. Hope your channel gains a bit more traction! All your projects are so fascinating

[@MattBrownbill]

A friend worked in a valve manufacturer, it involved a lot of hand polishing/lapping. Great to watch your inventive process. 👍

[@kurtkleber3268]

Klasse gemacht, bei Dampfloks gibt es am Rad noch ein zusatzgewicht damit der Zylinder besser rund läuft. Ich schaue gerne weiter zu, mach weiter!

[@gfr2023]

a cheap used metal lathe can boost your capabilities a lot... in any case I'm amazed by your mechanical skills

[@Doitgood52]

More thin lubrication and more weight on the flywheel Tim. You need to compound the motion! Love your work mate, from a very wet Australia!

[@conorgraafpietermaritzburg3720]

What you want is a slide valve which can be sealed with gaskets 😮 ,good luck I really enjoy your puttering about 😂

[@matthewgilbert1463]

I swear you have the most enjoyable content on all of youtube. I look forward to every video

[@phrozenwun]

Maybe try lapping your rotary disc into the body plates? Set your center wall height using a stack of shims and remove a shim - lap, remove a shim - lap,... until the rotary plate comes into tolerance... even I.C.E. valve bodies have to be lapped in order to seal effectively.

[@MarshallBF]

The rotary valve might work, if you seal it. There are seals that can hold easily up to 260 °C (FKM), I work only with "viton" which is up to 150°C, but it works as normal o-rings - even water is not a problem. Also, there are gaskets that might work. What I mean by the "might" word is that I have no idea about the dimension / air flow needed to exert required pressure. And as always, it is great to watch you work.

[@wayoutwest-workshopstuff6299]

Thanks, Jan. I shall do some more research..

[@lordmuntague]

This is good one-step-at-a-time engineering, excellent stuff.

[@bendordoy4815]

WOW I'm love watching the progress with your air/steam engine.

[@cadetkohr5508]

This is absolutely brilliant! If I may offer some observations, I think that the inlet valve is open too long, and the exhaust valve might be a bit late, causing some pressure to stay in for too long slowing down the piston. I wish I had the stuff to do what you do. You're honestly one of the best and most honest people on this website.

[@wayoutwest-workshopstuff6299]

Thanks very much - yes I think you're right about the valves. Apparently a little compression at the end of the stroke is a good thing though..

[@cadetkohr5508]

@@wayoutwest-workshopstuff6299 You are correct! I think that just moving the exhaust valve over slightly might just do the trick.

[@bsimpson6204]

Love the valve gear, it looks proper. Three cylinders and it would run beautifully

[@mischef18]

Enjoy watching and listening to your ways of doing things bro. Safe travels

[@mrstratau6513]

Heath Robinson would be proud. Great stuff.

[@ronarmstrong835]

I think Ducati would love your Desmodromic valve set up.

[@sebbes333]

*@Way Out West - Workshop Stuff* 10:33 USE COOLING liquids. You get better surfaces, less wear on the tools, and not as much heat expansion in the material, which is really important for high precision stuff.

[@leinadalan]

This is awesome!! You could use the sloppy cams as a type of govenor to keep rpm where u want it. Nice job!

[@TheHylianBatman]

Wow, seeing you do it almost makes me think I could do it, too. What a shame I never could. I love seeing the development here, you're very talented and clever. Good job.

[@lauraandedwardcannon8861]

That is so cool. I think you are on the right track. Most of the steam engines i have seen have a valve that looks like a little piston mounted right on the side of the piston.

[@stevecummins324]

may be less leakage, better economy of air use/ more flexability wrt possible timing adjustment etc to generate/process control signals that use small amounts of air that then pilot larger airflows via inlet and exhaust poppet valves for the cylinder... ( akin to the mechanical trip mechanism of corliss valve, or the hydraulic system of the engine on the 1929 Swiss Steam Ship Stadt Luzern ) small "bump" or lobe on flywheel. 4 roller actuated pneumatic control valves, arranged so as lobe on flywheel actuates them, they'll provide a short pulse of compressed air. those pulses provide the timing of the valve events. 2 air piloted pneumatic "flip flop" valves. these work almost exactly like an electronic flip flip, in that they remember the most recent input provided to them. the outputs from such a valve are then perfect for driving 2 air piloted main air valves; one valve for air in to cylinder; one valve for air exhausting cylinder valve timing can be adjusted by rotating the roller actuated pneumatic control valves around the flywheel, it would be feasible to arrange for such to do by a governor.

[@garethparkin9498]

Really loving this Tim! That rotary valve setup with the chain drive reminds me of the Bulleid Merchant Navy and Light Pacific locomotives of the Southern Region here in Britain.

[@geoffk229]

Thanks for sharing! Very interesting watching a trial and error process

[@caked3953]

I am most impressed by all the different ways and tools to tap holes with

[@roseroserose588]

That was an amazing 27th attempt, Tim! Great to see it working at the end, if a little ropey but that can be tuned out. Likely the reason you had issues with the sizes of your holes is down to the fact that drill bits don't create round holes, but oval ones. It will feel nice and tight, but there will be a gap somewhere. Generally when using a reamer you use a drill sized a little too small, then open to final dimension with the reamer after. This avoids the oval problem as the oval parts of the hole will still be smaller than your final diameter. Great stuff though, can't wait for the next instalment (:

[@andrewreynolds4949]

Many early steam engines and locomotives (and sometimes later ones too) were somewhat known for leaking steam from the cylinders. That’s part of what makes period industrial scenes so atmospheric.

[@Hyratel]

The shuttle valve used the steam pressure to hold the two sliding faces tightly together. If it's leaking steam, the gland packing probably need work

[@andrewreynolds4949]

​@@Hyratel Yes, my point was they had the same sort of tolerance issues back in the day

[@Hyratel]

@@andrewreynolds4949 you can get a perfectly flat surface from three rocks and some patience (whitworth 3-plates method, developed 1830s)

[@andrewreynolds4949]

@@Hyratel But patience costs a lot of time, and time is money. Not everyone can afford it

[@WayneCarolan]

Great progress Tim, I was looking forward to seeing this one! Well done. This one is close to my heart, i used a Scotch Yoke design for a project way back when in college when designing a can crusher… Goodtimes

[@jasonwhitler4167]

Looks and sounds awesome Tim. If you find out your getting too much friction from running the pushrod directly on the cam, it *should* be pretty easy to use a roller bearing as a follower on the cam. Some thick grease on the spools will also help them seal better. Keep up the good work!

[@treegodx5115]

POV your steam engine parts are all working:OH yea it's all coming together

[@tabriff3832]

I like your first design, and one gets the feeling that it is but a hair’s breadth from working. I love your second design. I always say, “You can never have to many moving parts”. And what a glorious sound, like the engines of yore. 🙂 PS If you can see, and hear what’s going on, you can fix it. A bit like my old MG. The engine, steering, suspension etc, were all on view and understandable, and when it wasn’t happy you could hear it, feel it, and in some cases smell it. A far cry from what greets you when you lift the bonnet of a car nowadays.

[@eby6114]

Two valves. One at each end of the piston. They would switch one being open for exhaust, one closed allowing the air/steam to drive the piston. It would switch open for the air to exhaust and the other side to push. Not sure if your familiar with reed swithes but that or a timed relay would probably work. More mechanical would be a switch that comes on at a preset points on the piston stroke for push and push. Thanks for all your hard work. Your very inspiring and I feel like we would be great friends if I lived nearby. My project last week was turning my box truck cooler into a solar powered cooler using 6 panels, and some Nissan leaf batteries. It works beautifully and I use it several times a week when away from home. Cheers

[@PotentialAutist42069]

very impressed with the cam system you designed

[@lukafilm]

Thanks for leaving the fails in, it was great!!!

[@devinholland2189]

Theres an easy to build steam engine valve called a wobble engine. The valve is controlled by the tilting of the cylinder and with only one flat slip face it functions very similar to your first valve.

[@YuriNGolfeto]

It's really funny how you talk about the process haha

[@PotentialAutist42069]

The early engineers used slide valves, not spool valves, which are kind of a combination of the two devices you built in the video. the spool valve was a later invention.

[@stevecummins324]

both very early engines and late steam engines used trip valves. which at the simplest are rotary valves with a lever arm, which literally got knocked (aka tripped) open and shut the valve, with motion of piston, or crank. Steam engine development, including that of valve gear, wasn't always continued improvement. there was a lot of avoiding infringement of existing patents

[@survroproductions200]

it's interesting how torpedo came from a steamer to a Rotary Disc Valve And Spool Valve Air Powered Locomotive. fascinating

[@CRIMSONDRAGON56]

Hey Tim, I’m an engineering student and I love the videos you and Sandra put out. I think I have an interesting way of solving your valve problem while also opening it to further expansion down the line for a powered push and pull stroke. For the single push stroke model you’ll need to make a box with 3 holes. Two on the top and one on the side. The first on the top will be an inlet valve hole and the second on the top will be an excess release valve hole. On the side will be the outlet hole with no valve. The valves will be made similar to those in an engine. A wide circle with some form of high pressure sealant along the outer edge such as rubber and a rod welded to the center of the disk. These rods will be inserted through the top holes and a powerful spring placed over the rods and centered over the holes and tacked in place to the box. The top of the rods will be threaded so a locking washer can be put onto the spring and the tension pulling each valve closed adjusted as needed. The inlet rod will have to be more complex than the outlet rod and will have to be a bit thicker and longer to make it work. So the inlet rod will have to be turned on a lathe to 2 diameters, thicker towards the disk and a second narrower section at the top to allow for the threads to retain the tension spring on the lower section. On the upper section of the inlet rod a set of 2-3 channels will have to be cut to allow for some small O rings to be put on the rod (hence the different diameters to prevent having to cut the threads over the entire length) Then a housing cylinder will have to be made for the inlet. If you take a bit tube and some round stock you can ream out the round stock to fit the smaller diameter of the rod (accounting for the o rings) then weld the pipe onto the round stock being careful not to get it too hot to prevent warping. Then drill and tap a hole on the side of the inlet housing to attach a quick connect for the air to come in. Adjust the tension on the inlet rod so it will stay shut at pressure then either weld the housing on or find a way to seal it and screw it on. If this is done properly you’ll be left with a sealed zone above the inlet and a rod sticking out the housing that releases the air into the main box when pushed. For the release valve you don’t need to put any housing around it at all. Now the interesting bit. Attach the valve box to the frame so that the rods point to the center of the wheel such that the rods are parallel to the axle. Reusing your 2 sets of cams and push rods set them so that they are 180 degrees out of phase or so. When the air is connected, the inlet valve will be shut until cam A presses on the push rod that hits and opens the inlet valve. Meanwhile cam B will disengage the release valve allowing pressure to build in the cylinder and turn the wheel. Once the cylinder reaches the end of its stroke inertia will carry it around disengaging cam A and shutting the air off while cam B engages the release valve and allows the pressure in the cylinder to drop and finish the revolution. By playing around with the shape and offset phasing of cam A and cam B you’ll be able to dial in the maximum power to speed ratio. I’m not sure why but I think you might want to make each cam about a 1/3 of a circle and play with the phasing until you reach the sweet spot. By adding a second box and some more cams and push rods it should also be possible to make a powered “pull” stroke as well by attaching the top of the cylinder to air as well but the timing would require a fair bit of testing to get your timing just right. If you think this would help at all send me a message and I’d be happy to help you work on some more detailed schematics. My email is [e-mail]

[@MassimoPizzoglio]

You can use the upper hole in the piston to "pull" the wheel in the "return" way, a "push and pull" system.

[@viriato8566]

Classic steam-power oscillating cylinder arrangement! Puff on Tim!

[@rukinaa]

A safer approach to the spool valve would have been to drill and ream the hole to be 12mm and use a oversized rod and remove material from the rod until it's a really snug fit. that's usually how I go about make these

[@Gin-toki]

or perhaps use piston rings since the spool is in essense a piston.

[@BrassLock]

@Brian J • That would be practical if Tim had a precise lathe, but his woodworking lathe is too "clunky" for such turning & fitting.

[@datguymiller]

This is why I suggested Stephenson's valve gear

[@wayoutwest-workshopstuff6299]

Thanks - that's basically a slide valve, isn't it? The con rods look complicated and the extra ones are just for reversing, aren't they?

[@datguymiller]

@@wayoutwest-workshopstuff6299 that's a bit of an oversimplification but yes, and the reverser isn't necessary from what I understand Edit: reverser also can change the speed

[@306champion]

Hang in there mate, you'll get it.

[@earlye]

Thank you for doing the R&D for a diy steam engine. As I've mentioned, I have a goal of eventually having a steam powered electric genny but don't have the time to tinker on it at the moment. Seeing your efforts is teaching me boatloads that I would have to learn by reading or trial and error later. I'd love to see what happens when you add a second set of valves to make the piston double acting, and even more valves to add a second piston.

[@wayoutwest-workshopstuff6299]

me too : - )

[@markchristopher9515]

You're doing great and having a frustrating ball. Fresh ideas in old tech come from ones who learn why they "didn't". Perhaps at another stage you could use Poppet's. Easy to fabricate & super tight with soft seat material from any rubber goods dealer.

[@wayoutwest-workshopstuff6299]

but would they work for steam?

[@markchristopher9515]

@@wayoutwest-workshopstuff6299 Absolutely, Watt's started using them and they're still on trains today.

[@tutekohe1361]

When I was young, my brother had a Kawasaki motorcycle with a rotary disc valve.

[@trainspottingfocsani150]

wow! this is so cool! i really want to see rhe final result :)

[@twkolejofil]

I like your concepts and especially the railway but those long loose sleeves by the lathe are just terrifying...

[@madmanmapper]

You could probably revisit the rotary disc valve if you put the air/steam input on the opposite side. If you look at steam engine valves, they are usually sealed by the steam pressure. Incoming steam presses down on the valve, sealing it to the valve block. For your disc valve, you'll need a seal of some kind on the rotating shaft. I guess a graphite gland. And you might want to flatten the mating surfaces of the valve and plate, might need your machinist buddy to do that. Still, it might yet be the simplest way for you to make a valve setup, given you have a plasma cutter. Also, you are going to want to get/make a double acting steam engine, and one with a much wider piston.

[@wayoutwest-workshopstuff6299]

Are you sure a wider cylinder will be needed? A long stroke is slower but has more torque..

[@madmanmapper]

@@wayoutwest-workshopstuff6299 I suppose it depends on a lot of things. What steam pressure you'll be running, the capability of the boiler, how fast the engine should move, etc. That's getting into engineering that I only have a cursory understanding of. I'm no steam expert. Just an armchair engineer. But look at old steam engines. Most have a big bore and not so long stroke. Maybe square or a little longer stroke. Just a thought :)

[@johncourtneidge]

Engine-ering is clearlt art and craft as much as science . . .

[@WFCinSC]

I was thinking for your rotary disc valve... if you provided a passage for the seal air to bleed out (path of less resistance that the path of blowby) you might get it working (though a bit inefficient wrt air usage).. Right now since you sealed the three outer plates the path the air takes to leak out is round the inner valve plate back to the outlet collector. So I am saying that on the inlet seal plate cut a collector groove that has an open passage to go out the inlet seal plate (not full depth and at a larger radius than the valve plate through passage, there could also be a corresponding groove in the valve plate). The added benefit is the pressure of the air should press the valve plate against the outlet seal plate and help suppress blowby. Ultimately I can see why you went another way since the pressure transfer efficiency will be a function of how well you can ultimately seal the 3 plates together, but as a bodge this might just get your concept "working".

[@wayoutwest-workshopstuff6299]

Yes, maybe, but I can just see it losing even more air : - (

[@WFCinSC]

@@wayoutwest-workshopstuff6299 no doubt that is a distinct possibility... always fun to see what you are up to!

[@Ashley-yn8xe]

So many people have no conception of the thought and tenacity that goes into something like this. Well done. As a thought, have you looked at how a mamod ('toy') steam engine works? I think they are brass and stainless steel.

[@pvtimberfaller]

Kudos on using the wood lathe, That’s what metal was machined on up until the industrial revolution. Research it. Spool valves weren’t used until the late 1800s, by then technology had advanced to the point that metal packing rings were common. Before that, D valves or 90 degree taps were the earliest ones used.

[@wayoutwest-workshopstuff6299]

Thanks, Ross. D valves are a sort of slide valve?

[@pvtimberfaller]

@@wayoutwest-workshopstuff6299 Yes, Without a good way to surface them you will run into the same leakage problems as the rotary valve. A spool valve will take a lot less horse power to operate though.

[@jpsimon206]

When you don't have access to machining equipment but you need a flat surface, you can use the three plate technique! Look it up, it's quite simple. The basic principle is that if you have three plates and none of them are flat, there is a way to ensure a perfectly flat surface by using the right combination of the three. I think even if you did not want to go to this degree, perhaps putting some grit between the two discs and lapping them together in a rotary manner, perhaps with a drill press, you could get much closer to a machined surface

[@wayoutwest-workshopstuff6299]

I did just that - with some fine carborundum paste. Perhaps not enough?

[@jamesgoddard8375]

Very impressive and interesting to watch. Keep up the good work

[@wayoutwest-workshopstuff6299]

Thanks James : - )