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His crowded drawings don't help!

It''s not a typo you need to look at the plans more closely. As Julius often spec's his main parts from aluminium which is not ideal as a surface for a cylinder there is a bronze liner to be fitted that is 48mm OD and 44mm ID. Part 1-07.02

The engine frame casting was threated much the same way as the one for nattie was. After fettling I used some drill bits to gauge the angle of the sides while feeler gauges were slipped underneath until things were equal all round. The casting along with the feeler gauges was transferred to...

1.5mm Wall should be OK

Pity you did not make the repair liek George said. With it still on the bar you can screw it in to check your thread depth and more importantly get it back out if your thread is not deep enough. As you have it it could get stuck and be very difficult to remove. Also to give it half a chance a...

Thats what I said eartlier and as the OP only has a file and no mill should be possible for him to do. "They can be made by fitting two pieces of tube over a central core, print some guides and use those to saw and file the ends of the tube to your profile."

here is one half with the bosses added And the mould that can be taken from it. Just drop a simple core into the space left by the core prints on the pattern and you are good to go

I simply did not draw them as it was not needed for the example. I would have thought it was obvious they they would pull out the sand OK with the position of the split line as mentioned. I also did not show draft But as Crest says they will all cast with the method we show and no risk of a...

Bluejets I was just pointing out that the engine in the video was not running diesel fuel but a model engine mix which is what the OP wanted to avoid using and is why he is asking about alternatives. Glow plugs, hot bulbs, etc would not be cheating if the engine you wanted to model had such a...

That Lister is not running on Diesel, it is running on model aero engine type fuel. Don't know if George ever got it to work on diesel, it was not the last time I spoke with him

I'd pattern it for moulding it on it's side and use a D shaped core. Split line would be horizontally through this image. I tend to think in terms that a commercial foundry will be casting anything I pattern and keeping it simple keeps the cost down. Once you start having to stick patterns and...

If you have the 3D file why not get it printed in a stronger material, one of the CF filaments or metal. With endless option sfor the shape of the groove of a "cylndrical cam" finding one off the shelf with the required shape for what you need will be very difficult. They can be made by...

Have a look at Dormer Pramet, just about all theirs are gun nose M2.5 is a small as I go with spiral flute, YG-1 brand for good work, cheaper for general Most of my threading is small so dies do the job. It is usually odd sizes that I need to screwcut or more recently thread mill on the CNC

You don't need a fluteless tap for that. Just use a spiral flute or spiral point. First lifts the spiral of swarf out the top of the hole, second pushes it forwards and is used for through holes, neither are backed off to break the swarf. Very good for hand tapping not just machine tapping. And...

Pat as I said back in post 38, you don't need a venturi. Go look a the small weedwackers and Walbro type carbs they are straight through. Two engines I'm working on at the moment have parallel holes no converging tapers.

Gives you a bit more solid cross section as the finer thread will have a larger core diameter. Also as it is a blind thread you are unlikely to be able to tap to the end so as the taper on taps is usually proportional to the pitch you will get a full thread further into the hole if it is fine pitch

But I don't think Brian likes screwcutting.

A finer thread for the plug would be better if you have suitable tap & die.

You need to remember that when these engines came out those making them had a steel rule and a pair of firm leg callipers. Engines were and still are "fitted" rather than made from a series of separate parts made to tolerances at least in the home workshop they are. Only experience will tell...

Brian, you have stripped 1/4 x 32 threads in other engines. Is it heavy handedness or are you using the wrong tapping drill and not getting a deep enough thread ? What plugs are you using, if something like a V3 they have very short thread length so more likely to strip than a standard length...