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

Fantastic stuff Phil,

I'll be watching and admiring!

Nick

Quote from: pgp001You might be interested in this, a rare opportunity to see a mill engine in build.

http://www.markhamgrangesteammuseum.co.uk/agnesrebuild.htm

Phil

Thanks for that Phil....as a member of a team that did something similar, I can appreciate the amount of work that went into that!

Dave

Hi Phil, fabulous work, thanks for the links.

Hugh.

Come on Phil: We need an update on Agnes  .

Have you been doing anything? (or maybe you should donate the castings  to me so that I can finish her off for you  )

Jo

What a magnificent engine, Phil. I missed out on the initial write-up and have enjoyed it tremendously today. I applaud your tenacity in getting the setups correct and the angles all worked out. If I had done it, I most likely would have wound up with a dud. Nice job. 


BC1
Jim

A quick update on Agnes as requested.

No progress at all in any shape or form.

Phil

P.S. See progress report on Boley Jig Borer

My thoughts are now moving towards getting on with Agnes again, I have just finished adding an inverter speed control to my Pultra lathe, so I think I am ready to continue where I left of and finish the new flywheel.

One thing that has bothered me a bit is the baseboard that Agnes is sat on, when dad made it back in the 1980's he used a slab of kitchen worktop that has a simulated tile effect to try and make it look like a floor. But to be honest I don't think it will fool anyone and in the time that has passed since he made it, the quality of finish on models at exhibitions has risen to new levels.



I have been wondering about what sort of flooring to cover this with, there are a few tiles available for dolls house floors, or you can buy a silicon mould and make your own using a plaster of paris mixture with some pigment.

Anyone got any suggestions for me on this one ?

Thanks
Phil

Hi Phil,
have a peek at this site , http://www.bloxxs.de/start.htm , type ZP-016 in the search window.
You should see a 24x12x2 mm tile.This is what I have  used for my last project.
Bye the way I am a fan of Agnes since I have seen the first pictures of Peters model some years ago.
The book is still laying on my desk.
Regards Achim

Phil it looks like a purfectly good building jig for now.

If you do it now is the base not going to get damaged sitting around for years whilst you finish the engine 

Jo

Hi Phil,
That is truly outstanding work on the flywheel. Other than the self satisfaction of knowing that it was made like the prototype I think I would have cheated a little and cast it solid with the details on the inside. It's going to be one spectacular looking engine when finished with all the links and rods moving about when in operation.
As a side note which you may or may not know, I was taught a trick when holding smooth pieces in the mill vise. Use a piece of notebook paper against the vice jaws to provide friction for the smooth surfaces. I have had the same thing happen when trying to mill parts.
gbritnell

Hi Phil,
Just caught up with your progress on Agnes 

That's some very impressive machining on the flywheel segments - I quite envy your facility for such elaborate machining set ups for angles 

Re the base work - I would strongly not recommend using Poly-Filla for the base surface. I use this method all the time for my plastic models and have made many bases now with varying forms of texture but it has one poor attribute and that is that it is easily chipped and that shows up immediately - I've even mixed it up with coloured dye and though that eliminates the 'white blight' it still does not disguise it.

I have used kitchen top on my steam engines so far but have always looked for the surface that has a very fine evenly dimpled texture. This can be scored if desired to represent tiles or slabs depending on size and painted to disguise any printed pattern.

The other alternative is to use Formica and machine that into tile or slab sized pieces. I have recently obtained some that has a very 'slate' like finish with a fine 'brushed' texture - Ha ha - this is for the Throp engine should that ever be so lucky as to materialise.

I do have a fair sized piece of extremely dense kitchen top as described above - if you are ever down 'Suffolk way' you're more than welcome to a piece

Keep up that great work - Ramon

A bit of an update on Agnes. I have been "slowly but surely" making some progress on the flywheel.

This photo shows the full size flywheel being re-erected at it's new location in Markham Grange steam museum, as can be seen the hub is a substantial casting with eight spokes being attached using wedges to pull them into the hub.



And the flywheel fully assembled, showing how it is also wedged onto the crankshaft.



My model will have dummy wedges, the hub will be secured using parallel keys onto four flats on the shaft, but there will be some socket grub screws fitted down under the roots of the spokes to hold everything in place.
The spokes will then be pulled into the hub using socket head screws down the centre of each spoke. Once the shaft, hub & spokes are fully assembled, the eight segments of rim can be fitted and machined in situ, then lastly the eight segments of the internal barring gear will be fitted and the teeth machined as a final operation.

The first challenge is to make a hub out of bar material so that it looks like a casting.
Here is the starting point for the hub, a chunk of 3" diameter cast iron bar.



One side was machined to the finished profile and bored to size all at the same setting.



It was then reversed and held on a mandrel to do the other side.



Next transfer to the milling machine and indexing head for the eight spoke holes. These will be bored over size and then fitted with protruding sleeves to mimic the casting.



Tapping size for the M5 spoke securing screws.



Opening out for the sleeves.



Extra tapping size holes for hub securing screws either side of centre.



A few sleeve blanks bored to size but still to finish on outside diameter.



Finishing a sleeve to size on a mandrel.



These sleeves will not be coming out again any time soon.





Having left to cure for 24 hours, the sleeves are machined to finished length whilst still in the indexing head.



Next lots of tapped holes.





The four equally spaced shallow keyways needed a special tool to use with my push broach to ensure they were spaced accurately. Here is one I made earlier.



One keyway is broached first, then the bush is indexed around 90° for each subsequent one.







This is what it looks like after four passes.



More to follow soon.

Phil

Nice set of pics!
Nice work too.
Very interesting.

Very nice  Looks like that bit of CI never made it into a collet chuck

Simon

Yes Phil, very intersting indeed. I like this kind of model engineering very much.