Poppin Engine build.

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ian_in_the_midlands:
Back onto the flywheels today.

The set of drill bits I have are Tin coated, so I could not flat the end as advised. As most of my drilling is probably in brass, I will buy another set and modify them.

Too impatient and the in-laws over, I needed to get on in the garage, so I continued with the drills I have. Taking the holes out very carefully in 0.5mm increments, I had no more problems.

I then reamed the holes to final size, and finally gave each one a tiny chamfer with a drill bit.

The wheels were then re-mounted onto the mandrel, and the chuck marks were skimmed off. The wheels 'rang' as I was doing this, and the result of this can be seen on the finish of the rims. Varying the speed had no effect on the surface quality. The picture looks much worse than it is, and a polish with emery paper removed this marks. The wheels are now slightly smaller (0.5mm in diameter, 0.2mm in width) than the plans ask. I do not think this will make any difference, but that will teach me not to turn to final size too quickly.

It can be seen in the picture that there are still some chatter marks on the inside of the rim. I can not get rid of these so will have to live with them. I will put the worse side inward when I assemble the engine so that they are not so apparent.

Finally I mounted both wheels on a piece of steel, pushed the bearings on the end, and held these in the lathe. Spinning the wheels by hand showed a minute amount of wobble on one wheel. I will wait until the engine is assembled to see how bad the problem really is before I start trying to fix anything.

ian_in_the_midlands:
After looking at the pictures posted I had to go and check :bugeye: - I think the marks on the first photograph that look like awful scratches on the spokes must be thumb prints, as I can not see anything there now. Panic over!

ian_in_the_midlands:
This weekend I moved onto the connecting rod.
A length of 2.5mm silver steel was drilled and cut to length.
I decided to harden the piston end, so it was heated to cherry red and quenched in water.
I then re-heated it to straw colour and let it cool naturally.

Slots on the brass parts were cut using a slitting saw with the piece held in the tool holder. The sides were then milled to size.

Everything else was basic turning/ drilling/tapping.
Once assembled, the hole for the crank was drilled and everything was polished. I turned a wooden dowel and used brasso to get inside the hole.
The steel shaft was then threadlocked in place. The photo shows how I aligned the axis by eye. The plans call for a rivet to hold the shaft in place, but I will leave this for now in case I need to adjust the length in the future.

I made the yoke a few days ago, again using the slitting saw.

The parts were then assembled. There is a slight skew. I suspect the hole may not be quite straight. I think it will be okay.

The yoke is attached by a piece of drill bit. It is only a press fit, but it is long enough that the inside of the piston will stop it falling out.

ian_in_the_midlands:
Everything assembled. Starting to look like an engine.

Now to make a start on the standard.
A 2" length was sawn from a piece of 1"x2" aluminium flat and faced off in the lathe to size.

That's enough for today. Now time to work out how I can make the standard without a milling machine :scratch:

vtsteam:
You're doing a really beautiful job, Ian. :clap:

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