Author Topic: Inspired by a Muncaster.  (Read 533 times)

Offline Jeff123

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Inspired by a Muncaster.
« on: October 21, 2018, 02:00:35 PM »
Ok Guys here we a go, my first engine build log.

Inspired by a simple single cylinder double acting oscillator designed by Henry Muncaster.

The diagrams below show the original engine and also a simple reversing valve.

My engine will be based on this design but will have two double acting cylinders positioned on the outside of the frames with the flywheel and valve in the centre. This arrangement is suggested by Muncaster in his book as an option to the single cylinder design. I am scaling the model up a little with each 1/16" becoming 2mm. So the 5/8" bore will be 20mm., the 1" stroke 32mm., and the 1/4" crankshaft 8mm. and so on.

Hope it is of interest as I go along but it will be well into the new year before completion. Winter is approaching and the 10-12 hours a week I spend whacking a little white ball around a big field will be coming to an end with that time being transferred to the workshop, so progress should be quite good.

As ever any constructive comments/advice will be appreciated. There will be no drawings apart from the most rudimentary sketches.

I would like to post on a weekly basis and as said earlier I hope you all enjoy the build.  Geoff

Offline Ye-Ole Steam Dude

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Re: Inspired by a Muncaster.
« Reply #1 on: October 21, 2018, 02:17:49 PM »
Hello Geoff,

I will be following along with interest in your re-design.

Have a great day,
Thomas

Offline Jeff123

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Re: Inspired by a Muncaster.
« Reply #2 on: October 31, 2018, 12:42:28 PM »
Hi All,

Somewhat unusually I decided to to make a reversing valve to start this model.

The design is in the 1912 Muncaster book and shown below.

Quite easy to make and it works really well. The main problem was getting a good airtight seal between the cast iron circular valve cap and body.

I lapped the two surfaces together with 1000 grade lapping compound and lots of oil. Patience was needed but eventually I got the two parts bedded together with no leaking.

This valve will sit in between the two main frames and will also act as a spacer.

Apologies for some picture quality, camera issues!!!

Geoff

Offline Jeff123

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Re: Inspired by a Muncaster.
« Reply #3 on: November 04, 2018, 12:37:45 PM »
Hi All,

On the original drawing for this engine (see below) the frames look like they were designed to either cast or fabricated.

I have decided to machine them from solid bar adding a little strength in the process. The drawing below shows the new frames scaled up 1/16" = 2mm.
This gives a frame height of 78 and width of  80. In scaling up I have "beefed up" the thickness of the frames.

Two pieces of 10mm plate have been dowelled together as shown in the photo. After machining this will leave the hole radii in the upper part of the frame.
So after much machining and hand fettling I ended up with the two frames shown below. The laminate base they are screwed to is of course only temporary.
I also added two shouldered struts to give the set up more rigidity.

Remember this engine will have two cylinders on the outsides of the frame with the flywheel in the centre.

Geoff