Author Topic: Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.  (Read 59813 times)

Offline pgp001

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Just managed to finish the eccentrics to go with the straps, here are a few photo's (I keep forgetting to stop and take photo's so they are a bit random)

Having cut the outer groove to be a good running fit in the straps, the blanks were parted off to width and then drilled and finally bored to size with a single point tool, I did not have a 13/16" reamer.



I then made a fixture that could be slid along the tee slots of the rotary table to give me the offset for machining the cutaways.



The following photo's show it in use.







The same fixture was then used to add the holes for the fixing bolts.



Here they are almost finished.



Phil

Offline Dave Otto

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Nice detail, good to see some progress in this interesting engine.

Dave

Offline crueby

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Great parts! And I love the idea for the sliding fixture on the rotary table, gotta make something like that...!

Online Kim

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Those eccentrics are really nice looking!  Like Dave said, nice detail!
The sliding fixture is a pretty cool idea too.
Kim

Offline Jo

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Nice to see some progress Phil  :)

Did you position the grub screws where you have so that you can use headed bolts while you set up the timing?

Jo
Enjoyment is more important than achievement.

Offline pgp001

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Grub Screws...........Who mentioned Grub Screws ? .........Not on my engine thankyou.  ;D

Those eccentrics are actually held in place with two hexagon head bolts at 90░ to each other, as per full size. The only difference on the model will be the screws will eventually have dimples drilled into the crankshaft once the timing has been established, the full size engine had some gripper pads between the ends of the bolts and the shaft. The bolts are going to be very fiddly to fit and then adjust the timing, so it could get interesting.
Seriously though I may use some grub screws initially until the timing is set, then swap them for the correct bolts later, It is one of my pet hates being able see modern fasteners on something like this, I dont mind if they can be hidden, but certainly not on show.

That fixture was actually a Graham Meek idea, he documented it when explaining how to mill the base and nose radii on small engine cams, so I just modified it a bit to do these eccentrics.

Phil

Offline mike mott

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I really like the look of those eccentrics.

Mike
If you can imagine it you can build it

Offline pgp001

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Re: Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.
« Reply #187 on: October 12, 2020, 11:49:04 PM »
This is the current state of play, I now have an "almost" finished Whitehead governor on the engine.







Phil


Offline Admiral_dk

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Re: Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.
« Reply #188 on: October 13, 2020, 12:40:10 PM »
I've completely forgot how big a project this one is  :o  - oh and nice parts  :ThumbsUp:

I can't remember - is the barring engine functional ?

Per

Offline pgp001

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Re: Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.
« Reply #189 on: October 13, 2020, 12:50:00 PM »
Yes definitely a long term project.

And yes the barring engine has run on compressed air.

Phil

Offline box853

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Re: Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.
« Reply #190 on: January 26, 2021, 11:22:02 AM »
Hi - This is all of very great interest to me!! I come from New Mill - just outside Holmfirth - and from about 14-17 used to cycle to Washpit Mills in school holidays when Herbert White used to let me help in looking after Agnes. I gradually progressed to him letting me start it up for the morning shift, and shutting down in the afternoon, although for obvious reasons he thought it best I didn't slam in the plug thing for synchronising the generator (Mather and Platt) to the mains. I think what you're doing is absolutely wonderful - at the time I was seeing Agnes (my hot and steamy girlfriend!!!) I was also making a Stuart Turner No. 9 model engine in my spare time at Honley high School so seeing your work is totally brilliant!!! The engine still works! -
and

I now make accordions (www.briggsaccordions.com) and have my own charity where we use specialist technology to enable people with disabilitites to make and play music (www.omnimusic.org.uk). I'm over in Manchester and would love to visit some time if at all possible when the Covid thing has passed!

Anyway, now I've found this page of yours I'll be following the progress of your work with great interest! Totally brilliant!!!!!

doug


Offline pgp001

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Re: Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.
« Reply #191 on: January 26, 2021, 05:41:20 PM »
Hi Doug

Nice to hear from someone who has actually seen Agnes in her original location, my late father used to go see Herbert White and Agnes back in the 80's and I have the photo's my mum took to prove it.
I did get to start Agnes myself a few years ago when I went on one of my fact finding trips to Markham Grange steam museum where she now lives. They have been very helpful and allowed me over the fence to take measurements and photo's etc.

This is a long term project and I seem to go in fits and starts as and when I am in the mood, I flatly refuse to make any parts unless I am in the zone, if I do force myself I end up not making things to a high enough standard.
I have not put any updates on here for quite some time, the problem is it takes ages to do photo's as well as make the parts, and then all the editing and writing up of each stage is very time consuming.
So what I have decided is to crack on with cutting metal and take a few photo's when I remember, then as each sub assembly is done put a selection on here.

I have just spent at least ten hours hogging cast iron chips from the upper and lower steam chambers in both cylinders, I am just about to cut the actual steam ports in them when I pluck up the courage to try the 0.048" slitting saw. I will be glad to get that stage behind me.

You are welcome to come and see my Agnes once travel is allowed again.

Your accordions look fantastic by the way.

Phil

Offline pgp001

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Re: Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.
« Reply #192 on: March 30, 2021, 08:09:23 PM »
I have been doing a bit more on Agnes.

The casting for the condenser was always going to be a problem, Peter Southworth must have mis-calculated the height of it when he made the pattern and it is 3/8" too tall.
So I decided the only way to deal with it was to cut the bottom off it and make a new one to fasten in.

This is the setup for machining the base off it.


The pipe flange was cleaned up at the same time, although I later removed that completely and fitted a new one as there was not enough room for any nuts and bolts.


This shows the setup to take a measurement for the new base height.


A chunk of cast iron was machined up to be a good fit inside the condenser casting




It was held in place with four contersunk screws in the end walls, followed by a bit of my favourite 3M putty to simulate some casting fillets.
I dont think it turned out too bad.



Phil


Offline scc

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Re: Agnes.... 1/16 Scale Pollit & Wigzell Tandem Compound Condensing Engine.
« Reply #193 on: March 30, 2021, 09:06:35 PM »
Hi Phil,     Lovely to see Agnes progress again :ThumbsUp:   I suppose modifying castings is almost as much fun as making from barstock ;)
Terry

Offline pgp001

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Sorry I have not been updating this lately, I have done a fair bit of work on the cylinders though.

The problem is I keep getting distracted, this is the latest one.





Phil