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Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.

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MuellerNick:

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That's the pattern for a new segmented flywheel.  :)


That engine looks really nice! Very promising so far.
Is the paint a very dark blue or a black?


Nick

pgp001:
The bedplate is made in three castings exactly as per full size, the overall length of the base board is 36" and the currently fitted flywheel is 11" diameter.
My dad did make his own working sketches for some of the parts you see, but in the main it has been made by scaling down the original P&W drawings that still exist for Agnes. Luckily I have full size drawings for most of the main castings and valve gear parts.

I have been corresponding with Bradford Industrial Museum, and they may have found a couple more that I do not have.
However, I am doing a full set of scale drawings in Solidworks 3D just for my own use and to make sure it all fits together.

The colour of the castings is black at the moment, but I am considering whether I should paint in the colour scheme it is now, ie burgundy.





The pattern is indeed for the flywheel segment, more of that in the next installment.

Phil

b.lindsey:
Lovely engine Phil, both in full and model scale. I am quite interested in how the segmented flywheel will be done too.

Bill

pgp001:
This is the stage I have got to with the Solidworks 3D assembly of Agnes (See PDF file attached below)

When Peter Southworth built his two models of Agnes, it was never his intention to add this model to his range of commercially available castings, remember I told you how he had passed on the patterns to a friend with instructions to burn them. I think that showed fairly clearly that there were no additional models planned.

At this stage I must publicly thank Bob Potter, Bob took over Southworth models when Peter died and has been an enormous help in compiling information about Agnes. It was Bob who discovered that Peters wood burning friend had not actually burnt the patterns after all, but put them in his loft and never told anyone. Bob did some negotiations on my behalf and I have now taken over as custodian of the full set of Agnes patterns, and they are currently stored safely in my loft.
Peters wishes will be honoured and no additional engines will be built using the patterns, but I will arrange to display them along with my model when it is finished, giving full credit to Peter for making them.

Prior to me becoming custodian of the patterns it was agreed that I could have a set of flywheel segments cast in order to correct the one on my model, so that is what I have done and I am sure both Peter and my dad would have approved.

The pattern you have already seen was sent to a foundry in the West Midlands, and I had nine segments cast from it, I got one extra done in case of any mishaps, so far all has gone well. It took a while to figure out a method of machining them all so they formed a perfect circle when bolted together, each one had to be exactly the same.

These are the castings.



The first job was to remove most of the lump left over from pouring the casting.



The problem with these is how on earth do you hold them whilst maching them, I decided that the second operation would be to machine the side faces to give some sort of flat datum to work from, so I made this hold down bridge to wedge into the casting so I could clamp it to the mill table. This was the first of quite a few special bits of tooling  :)



I used an carbide inserted cutter to face off both sides of each segment so they were all the same width, these faces will ultimately be finish machined in the lathe when the flywheel is almost built up.



There was no way I could fathom to hold these in a vice and be able to machine the angles at either end with any sort of repeatability, so I designed a holding fixture for this job. I had a lump of aluminium under the bench which was just about right luckily.



So let the swarf begin.



Until a few evenings later I ended up with this.



Can anyone guess how I intended to use this ?

Phil

Maryak:
Beautiful engine Phil,

The thing that has me intrigued with the flywheel is how the spokes are held to the centre boss. The GA has some axial circles on the boss so I am wondering are the spokes pinned axially so that the bolts spokes to rim line up?

Best Regards
Bob

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