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« Last post by airmodel on Today at 12:17:57 AM »
Here is a video about an arc furnace which shows that just because the arc flame has a very high temperature it will be successful in melting high melting point metals. The problem with this furnace is it needs lots and lots of kilowatts and having a electricty supply to have lots of kilowatts is not available in your home. This applies to any kind of furnace that uses electricity to melt metals. An oxy acetylene torch has a very high temperature flame and has the same problem it will not melt a kilogram of steel. My oil burning furnace can melt 14kg of cast iron in 50-55 minutes but the amount of kilowatts the oil produces is about 70-80 kilowatts, any less than that it will take a lot more time to melt. At the end of the video he says that an induction furnace will solve his problems but there is another problem to solve, does he make the power supply for the induction furnace or buys one? Watch from 12:38 to 17:06
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« Last post by vtsteam on January 18, 2026, 11:23:56 PM »
Yes, I think they look fine!
Guy Lautard in one of the Machinist Bedside Readers outlines a method of ball turning using successive X and Y moves using calculated coordinates. I've never tried it, but I'm sure it works. Basically what you did by eye, except to a table of moves. Seems like a useful way when a mechanical ball turner can't fit the turning space, or isn't available.
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« Last post by Vixen on January 18, 2026, 11:09:00 PM »
Back to YS pump, notice the 2 identical (55) pump valves + (56) springs facing opposite direction, 2 identical windows on (59) gasket. Is it double acting pump? There is only one port hole in the (57) pump plate
No, the YS pump is single acting. It only pumps on the up-stroke. The plunger (part 60) operates in the lower finned portion of the pump body (part 54). When the plunger descents, the lower check valve (part 55) unseats, drawing fuel from the tank through the lower hose connection. When the plunger rises, the lower check valve re-seats and the upper check valve is forced open, fuel is pumped to the upper hose connection. The diaphragm (part 57) will only act upon the fuel pumped to the upper hose connection and will only release a 'shot' of fuel when the engines intake stroke creates a signal. If only we had one on the bench. Cheers Mike
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« Last post by vtsteam on January 18, 2026, 10:31:36 PM »
Back from the distraction of a "real" steam engine.....  to the world of a 1-1/2" bore. I turned a piston up out of material on hand from a casting session riser. First to rough overall dimensions and then tapped the center 5/16"-18 tpi. Then I parted it off. I then threaded the end of a piece of 5/16" drill rod to fit and screwed the two together. The piston rod with piston attached was then mounted in the lathe chuck, and both ends of the piston were cleaned up with a parting tool, bringing the final piston width down to 5/8" final. The piston diameter was then turned down to a close sliding fit to the cylinder. I added a thin jamb nut to the end and tried it out in the cylinder with the covers on. With no lubrication, gaskets, packing or rings, the piston will fall the 2-1/4" stroke of its own weight, and take a consistent 12 seconds to do that. I had originally thought about making CI rings for it, but I'm considering just trying V-groove labyrinth seals for the piston. Both the cylinder and piston are iron, so temperature expansion should be pretty much the same. Might just give it a try. (btw, I do know about O-rings, but I just wanted to go full metal on this one). Anyway, progress,,,
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« Last post by petertha on January 18, 2026, 10:06:16 PM »
YS (Yamada manufacturing) holds patents for their various engine developments. Serious business for our 'weekend toys'. I only mention because some people have a knack of extracting useful info from patent docs.
I believe YS is still independent. Historically some of these Japanese 'model' manufacturers have lineage or ties to significantly bigger industrial arms/resources. Futaba (RC) is a tiny offshoot to a mega electronics parent. I think they acquired OS engines in the 90's. Sorry for all this RC chatter.
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« Last post by petertha on January 18, 2026, 09:43:26 PM »
As a matter of interest, what is the typical push rod stroke for one of these big 23cc engines? It may some indication of the pump stroke.
You have mentioned 'jerk' pump on a couple of occasions, can you explain that term.
I no longer have a YS to measure cam action & rocker length but could probably get that info over time. I seem to recall a more detailed review article of original 120-140 series, maybe by Peter Chinn or similar back in the day. YS is not in his book which was already out before this time. The high CR & relatively big valves & head layout suggests low-ish valve action, but that's just speculation. For sure they were already using different sized valves & timing to extract maximum poop. I suspect YS Dingo engines/owners are a lot more scarce unfortunately. I believe YS has stopped producing them. The last WC's was something like 95% electric powered, sadly the glory days combustion has made them more of a novelty, but that's another topic. My understanding of a 'jerk' pump: the plunger action is a result of a relatively sudden impulse from a cam or bump mechanism, as opposed to a smoother 'continuous' pump action from gears or rotor. Whether this is by design specifically to yield the volume spike over relatively short time, or a byproduct of more primitive drive systems in the past I cant say, but I think much the same end result. I've also heard jerk used in old-tymy oil & mining industry context where cable systems actuated machines/mechanisms 'jerked' them to do one thing or another. How this potentially relates to the human characteristics I'll leave to your imaginations haha Back to YS pump, notice the 2 identical (55) pump valves + (56) springs facing opposite direction, 2 identical windows on (59) gasket. Is it double acting pump? There is only one port hole in the (57) pump plate
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« Last post by Sanjay F on January 18, 2026, 09:37:49 PM »
From the picture they look fine and are governing a beer bottle! 
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« Last post by Sanjay F on January 18, 2026, 09:34:03 PM »
Hello from Essex UK and welcome to the UK; I started machining only a few years ago and on a small Chinese lathe and mill, nothing like what you have the pleasure of working with. My first engine was the Stuart 10v and as a complete novice I managed to make it operational. Since then I’ve gone on to make several of Stuart models and they are great choice though on the pricier side. Enjoy the forum and look forward to seeing your first project regardless of what it is  
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« Last post by AVTUR on January 18, 2026, 08:53:32 PM »
Hi, from a flu ridden UK (at least as far as I am concerned)
You will get lots of advice as far as the first model to build but here goes: Stuart (used to known as Stuart Turner). Reasons
1. The model looks like an actual engine.
2. They are well designed and mistakes in drawings disappeared years.
3. They imperial which may suit you BUT the threads are BA which is strange in the USA.
4. The castings are good (that is slightly oversize without hard spots)
5. When you produce a scrapper they will happily sell you a replacement.
6. If you choose to collect, I guess people do from the USA, the foundry is in a beautiful part of the UK. (This is where those in the UK pile in to say Dorset is not beautiful).
These models were frequently built made by apprentices when they discovered that the training staff were happy for you to do your own thing instead of making endless mop buckets. In addition they entered the school metalwork classes. Most were unfinished, put on the shelf and returned to many, many years later. My unfinished Stuart 7H lived for over 40 years in a nice cardboard box until a retired collegue from work persuaded me to finish it.
Likewise my niece started a 10H at school only to stop when she to university, work, marry and have a child. It is safely stored at my sister's.
Enjoy the retirement and model making.
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« Last post by Fj45 on January 18, 2026, 08:42:00 PM »
Mike,
Rodger mentioned that the Shillings system is constant flow. I realized that when the engine stalls the mechanical pump stops pumping. An electric pump would need to shut off instantly and residual pressure be released or the nozzles would dribble at least, flooding could make restarting difficult. Maybe not such a good idea.
Can't help thinking you and Dave are onto a much better idea using an auto EF Injector as a metering device feeding 1 end of a common rail.
Just to be clear .. the hollow tube slide valve, capped both ends, with nozzle firing down one end would act both as throttle (air meter) and as plenum chamber.
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