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Tug, if I'm understanding what you're saying correctly, should you also be recommending that the front housing be fit so that the outer race can move fore and aft, to find its own happy place? Because otherwise it could end up loading the balls against the races just by how its positioned in...

Two nominally nice plates. I say "nominally" because the second one is a bit - uh - not flat. It's probably within about 0.01 or maybe even 0.005 now, though. The sheet that I cut this from was banged up in one corner, and I think that wow extended into the circle there. Fortunately, I have...

One plate, 4.497" in diameter -- I keep hitting these things a bit small! The other plate, ready to be tossed into the 4-jaw. I'm using double-stick tape to hold the plate to the round bit of plywood that I'm using as a chuckable piece.

Top and bottom plates. Made from some scrap aluminum sheet that I got God knows where. I'm going to see if I can turn these into nice round four and a half inch diameter circles. I don't know if I'm going to keep the wood grain or if I'm going to try to remove it. I'm sure it's going to...

If you just bung a longer plug in there you definitely want to check for clearance before flipping the prop. I suspect it was just designed for a long reach plug, though.

With apologies to Mario if this is unacceptable thread drift (but it kinda sorta bears on the problem, so...) I'm going to make this complicated. A true Diesel engine works because the air is compressed an insane amount (20:1 or something like that). This gets it so hot that when fuel is...

"Nice bouncy feeling when flipping the prop" sounds like the engine seal is good, but you could get that with a wide range of compression. I hadn't thought this before -- is the engine designed for that size plug? If the head is designed for long plugs then a short plug like the OS will be...

I've built several needle valves for RC to CL conversions. If the needle isn't round and centered then you'll get that effect. So I think another needle is in your future -- possibly one that has a longer taper. Post a drawing of your needle design? As for compression, I'd just take a swipe...

It sounds like it's in a rich four stroke, or it's sick, or it's not broken in yet. Do you have good compression? Is it broken in? What plug are you using? If it's broken in it should turn freely with the glow plug out. If it still binds at the top of the stroke, then you need more...

I worked for a company building infrared cameras. we used a part that was electroformed by plating copper onto an aluminum form and then dissolving the form with acid. So it's certainly a known production process for making intricate shapes out of easily-plated metal like copper. I'm not sure...

So where you you source a hunk of graphite for a power piston? I'm tempted to start out with an aluminum piston and some graphite lubricant.

It's a displacer cylinder! It was supposed to come out one inch long, but it's about five mils short. I'm going to keep it.

I think you should anchor it to an ultralight that can fly on five or ten horsepower, and then do the obvious!

Oh, the sound is amazing! I love it.

I have a lot of scrap, bought by the pound at the local scrap yard. Some of it came stamped with the alloy (i.e, I know my 6061 is that, because it says so). Some of it is mysterious, ranging from what appears to be 4041 steel to some really high-alloy stuff that's a pain to machine that I...

I just realized this should go into the "Engines" forum. Oops. If any moderator reads this -- feel free. At any rate -- decades ago I bought a 3" long piece of 4" diameter acrylic tubing for this engine. It's been patiently waiting. Today I turned a tool to turn a tool, then I turned a tool...

Is there something specific you want to build? I'm not sure what they're called in Australia, or if they exist, but in some states in the US there's schools called "community colleges" or "junior colleges" that are publicly funded and teach trades, among other things. If you're a total newbie...

Do you know what size it is? It looks like an 049 case, but I know Cox made a few larger versions with that same shape case.

Large & thin wall as in 4 inch diameter, 1/8 inch wall, acrylic tube. Any attempt to just put it in a chuck results in a severely distorted tube. I'm thinking that I should either turn a piece that fits just inside the tube or making a cross-bar jack thingie. The turned piece has bonus of...

If things work out, this is going to be a really excruciatingly slow build thread for a low temperature differential (AKA "coffee cup") Stirling. If not it'll be yet another abandoned thread. It's going to be a "Plans? Yes, I'm planning to build an engine!" sort of build. But I am looking...