Author Topic: A Simple Uniflow Engine  (Read 19659 times)

Offline MJM460

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Re: A Simple Uniflow Engine
« Reply #390 on: April 12, 2021, 01:10:04 AM »
Hi Gary, still watching along.  Great progress.

Perhaps a bit of rotary table work for those smaller radii would reduce the filing required?  It will also work for some of the internal cutouts.

MJM460



The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: A Simple Uniflow Engine
« Reply #391 on: April 12, 2021, 10:09:45 AM »
Hi MJM -

Thanks for this.

I guess that would be a good way to do it, but methinks I'll just freestyle it with either the small or (more likely) the large belt sander....

Offline gary.a.ayres

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Re: A Simple Uniflow Engine
« Reply #392 on: April 12, 2021, 11:39:40 PM »
If it wasn’t so hazardous to arteries I’d suggest leaving it for that “steampunk” look.

Actually, Stuart, at this point it has now developed a look that's more dieselpunk than steampunk.  8)

I began on smoothing out the edges of the the two sides bolted together. This amounted to a 12mm thickness of aluminium plate, and I'm saddened to report that this here small belt sander gave up the ghost under the stress of it:



It may just be a fuse, but if it's the motor then so be it. It may make quite a nice little machine to power with a 35mm bore uniflow engine...

So then I tried the belt sanding attachment on my Coronet Major 'wood lathe and multi-function wood machining centre'. I love this vintage British machine and it has an exceptionally powerful motor. Perhaps I went at it a bit too enthusiastically because the still-jagged chain-drilled edges of the plate shredded the belt, which can be seen here lying under the machine:



Good job I have other belts for it.

Surprisingly, the best solution was a small drum sanding attachment held in the drill press:



I went through a few belts but it didn't take long (less than two hours) to get the sides pretty close to finished shape:



I'm really quite pleased with this. The edges may need a tiny bit more finessing but it's not too bad at all. It has a shape that evokes to me a butterfly's wing. This wasn't intentional - it just emerged from the process.

In order to take stock and make decisions about the placement of decorative holes in the frame, I reassembled the engine:









Before dismantling it yet again to drill the holes, I will also mark out the ends of the angled frame support bars so that they can be cut to follow the curve of the frame sides at the bottom.

Offline crueby

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Re: A Simple Uniflow Engine
« Reply #393 on: April 12, 2021, 11:45:38 PM »
Love the shape - you have a great eye for swoopi-ness!

Offline gary.a.ayres

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Re: A Simple Uniflow Engine
« Reply #394 on: April 13, 2021, 12:05:27 AM »
Thanks Chris.

There are a couple of areas along that top curve that don't flow quite as I'd like them to, but they're pretty minor. The trouble is it can be a game without end trying to smooth these kind of bits out, so I may or may not go back to them.

It's amazing how sensitive the human eye is to even tiny glitches in a curve. Overall I'm happy though.

 :ThumbsUp:

Offline propforward

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Re: A Simple Uniflow Engine
« Reply #395 on: April 13, 2021, 01:04:39 AM »
Looks pretty excellent to me Gary!
Stuart

Offline Kim

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Re: A Simple Uniflow Engine
« Reply #396 on: April 13, 2021, 02:25:48 AM »
Love the curvy frame, Gary!

Sorry about the belt sander and the chewed-up belt, etc... Glad you finally got there!

Kim

Offline gary.a.ayres

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Re: A Simple Uniflow Engine
« Reply #397 on: April 13, 2021, 09:52:50 AM »
Many thanks guys.

@ Stewart - it's not too bad. Being picky with myself I can see a slightly clunky bit of the top curve at about two o'clock from the bearing hole. It's minor, but if it keeps bothering me I'll try to take it out later.

@ Kim - yes, some things turn out to be sacrificial. I did go in a bit recklessly, to be fair. I seem to remember that the drum sanders worked well on my oscillator too, so I should probably have re-read that thread before I started with this. But I do quite like the idea of driving the small sander with this engine if it can't be fixed...

Offline gary.a.ayres

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Re: A Simple Uniflow Engine
« Reply #398 on: April 17, 2021, 11:17:38 PM »
I have two little drip-feed oilers that I bought from PM Research quite some time ago for another (as yet unstarted) project, so I thought I'd use them for the bearings of this engine. They have a 1/4 - 40 UST thread, which the PM Research website says is compatible with the UK 1/4 - 40 ME thread. I have a tap and tapping drill for the ME thread so I thought I'd test it on a piece of brass bar:



It fits fine. I also checked the oiler for oil feed rate:



It appears to give a good range according to adjustment.

Next up, the cylinder drain cock (only one as the engine is single-acting). The best place appeared to be in the cylinder end cap, as low down in the bore as I could reasonably get it. There wasn't much room for manoeuvre, but I'm happy with the position. The location was marked out using the digital height gauge, centre punched...



... centre drilled, drilled and tapped. The tapping operation was done using tapping mode on the mill, which is good for tapping open-ended holes once you get used to it. The drain cock was then given a trial fit:





Then - changing tack - the engine was taken apart yet again and the process of making the cutouts in the frame sides was begun, using hole saws. As luck would have it, the four hole saws that I keep in my shop were exactly the right sizes for the four main holes that I wanted to cut! So here goes...



More holes coming up...


Offline gary.a.ayres

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Re: A Simple Uniflow Engine
« Reply #399 on: April 18, 2021, 09:29:51 PM »
More holes:





Just a lashup for the sake of the look. The next step is to shape the frame mounting bars to follow the curves of the side plates.

Offline crueby

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Re: A Simple Uniflow Engine
« Reply #400 on: April 18, 2021, 09:54:51 PM »
Those curves are crying out for some pinstripes. Maybe some hotrod flames... Nice!!

Offline gary.a.ayres

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Re: A Simple Uniflow Engine
« Reply #401 on: April 18, 2021, 11:29:27 PM »
 :o :) :ThumbsUp: