Author Topic: Clarkson Twin Horizontal Steam Engine  (Read 2168 times)

Offline Mike Bondarczuk

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Clarkson Twin Horizontal Steam Engine
« on: October 03, 2018, 12:41:27 PM »
Hello all,

Have finally started on the Clarkson Tandem engine build as per the Blackgates castings, which I had purchased some two years ago from Jo.

The kit was incomplete but I have ordered the missing castings, where appropriate, and will collect them at the Midlands Exhibition in two weeks time, and I am planning on building it as a tandem with 2 LP cylinders and not a tandem compound with HP and LP cylinders.

However, to get things rolling I have started on the build and it seemed that the first action should be to keep Jo happy, so I decided that the cylinder block assembly with steam chest and cover should be held together with studs and nuts, and I trust that she approves.

The next series of interconnected parts are the crank discs, con-rods, crank pins and axle, and these are all from stock as per the drawings.

I have started on the cylinder blocks and got them down to within 25thou of the finished size, all nice and square and just waiting for the steam chest to be able to confirm the cylinder bore centre.

Hopefully work will progress at a  faster rate once I have the remaining castings though already have some questions regarding the main bearings and bearing caps as from the drawings the castings seem to be extremely tight in machinable material.

Mike
« Last Edit: October 03, 2018, 08:08:39 PM by Jo »
"Everything I can't find is in a totally secure place"

Offline Jasonb

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Re: Clarkson Tandem Compound engine
« Reply #1 on: October 03, 2018, 01:00:49 PM »
Look forward to following along.

Just one point a "tandem" engine is one that has the two cylinders in line with each other ( think tandem cycle), what you have there if it was built as a compound would be a "cross compound" or with the steam going straight into both cylinders will be a "twin" or double high" as the steam will be classed as high pressure from the boiler rather than low (expanded) steam from a HP cylinder.

I think I would be tempted to add some bronze bearings rather than run straight in the cast iron which would allow you to put the bearing in at whatever height you wanted if the base casting was too low, you have double the amount of bearing caps so can split them off ctr if required.

I'd also go for a 2 bearing crank not 4 and swap the baseplates over putting the flywheel into the inside of the "L" shaped base castings but that is probably a bit further than you want to go ;)
« Last Edit: October 03, 2018, 01:07:15 PM by Jasonb »

Offline pgp001

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Re: Clarkson Tandem Compound engine
« Reply #2 on: October 03, 2018, 01:24:57 PM »
Jason

I tried reversing the baseplate castings on my 3D CAD assembly as you suggested, but it does not work out very well in practice.
I think on mine I will remove the existing bearing lugs from the castings and make up some new ones to form a single bearing either side.

Phil

Offline Jasonb

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Re: Clarkson Tandem Compound engine
« Reply #3 on: October 03, 2018, 01:32:47 PM »
I'd only traced it off the drawing quickly to see if it would work, i seem to recall that one of the pads for the cylinder would need building out to help line things up . New bearing supports would make it easier and you could beef them up a bit which would look more appropriate maybe 4 studs per cap.

If I do one then it won't be a problem as I doubt I will use castings, maybe just a couple of 4" flywheels. I'll draw something up at some time maybe twin 24mm bores to go with my other engines or 18/30 compound that could be plumbed either way so you can run as a compound on steam and double high on air.

Anyway back to your thread Mike.

Offline Jasonb

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Re: Clarkson Tandem Compound engine
« Reply #4 on: October 03, 2018, 03:20:43 PM »
Back to the main bearings I notice there is a bit of an anomaly in the drawings (Clarkson Drawings).

The cylinder casting ctr height is shown as 1 1/16" and this sits on a pad that is cast into the top of the bed casting so lets say the pad stands proud by 1/16" after machining. This gives the engines ctr line at 1 1/8" above the top of the base casting.

The ctr of the main bearing is shown as 1 1 /16" above the top of the bed casting and it has no pad being part of the bed casting.

This gives an error of 1/16" which could be sorted in a number of ways depending where the casting has more metal than needed or where it may seem a bit tight but the extra 1/16" may help matters. Without a set of castings in my hand it's hard to say, maybe as they have been fondled a lot by Jo's hands she could shed some light on this unless it was one of the reasons she parted with them ;)

Offline Mike Bondarczuk

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Re: Clarkson Tandem Compound engine
« Reply #5 on: October 03, 2018, 03:31:39 PM »
Hi Jason,

Thank you for the input and you are correct in that it is not a tandem I shall be attempting to build but a twin so will have compressed air entering both cylinders simultaneously, and hopefully timing will not be too much of an issue for balancing for smooth running.

The drawings as supplied are rather sketchy and leave a lot of analysing for final numbers so your comments about the crank height are very valid, and an earlier build log on here, from Canada, actually went your route with bronze caps mounted on undercut pedestals allowing for the crank to run totally in them rather than have a cast iron, gunmetal interface for bearing surface.

Mike
"Everything I can't find is in a totally secure place"

Offline Jo

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Re: Clarkson Twin Horizontal Engine
« Reply #6 on: October 03, 2018, 04:09:31 PM »
Yes it is a Clarkson Twin Horizontal engine Mike. The Compound engine has the second cylinder a slightly different size cylinder & bore but for running on compressed air the twin is better  :)

However, to get things rolling I have started on the build and it seemed that the first action should be to keep Jo happy, so I decided that the cylinder block assembly with steam chest and cover should be held together with studs and nuts, and I trust that she approves.

 :ThumbsUp:

As for the crank height there is no drawing for the base plate other a sketch showing the height of the bearings and that should be the height from the bottom of the cylinder not to the unmachined surface of the base plates.

I think I mentioned to you Mike I still don't like the original Clarkson crosshead guides Erics ones were rather thin and very hard when we tried tickling them with a file  :disappointed:

Jo

P.S. Please don't mention anything about me selling castings to you the sale pre-dates Surus' arrival and you know what he is like about protecting his castings   ::)
Usus est optimum magister

Offline Mike Bondarczuk

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Re: Clarkson Tandem Compound engine
« Reply #7 on: October 03, 2018, 08:02:04 PM »
Hi Jo,

Thanks for the clarification and would  the photo with the castings be the items which are missing from the original kit or just a random picture of Clarkson castings for what looks like a single.

Mike
"Everything I can't find is in a totally secure place"

Offline Jo

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Re: Clarkson Tandem Compound engine
« Reply #8 on: October 03, 2018, 08:05:16 PM »
Those are a picture of some of Eric's castings that I took so that I knew what was missing from the set you now have.

I think at the time I mentioned to you that Eric and I decided that the original crosshead guides were chilled  :disappointed: and it would be better to make them out of bar stock

Jo
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Offline pgp001

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #9 on: October 03, 2018, 11:11:12 PM »
Just for reference here are a couple of pictures from my Solidworks 3D assembly of this engine so far, it can be seen in the second image that there is very little material to play with around the main bearing pedestals and the crankshaft actually stands proud of them.





I will be making various detail changes to the design, but I am just modelling up in CAD what I have to start with from the existing castings and drawings.
Ignore the con rods, they are just temporary dummies to simulate getting the engine to turn over for checking valve events etc.
Phil

Online b.lindsey

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #10 on: October 04, 2018, 12:50:13 AM »
A nice looking engine Mike, will look forward to watching your progress on it. How did you manage to wrestle the castings away from Jo?  :thinking:

Bill

Offline crueby

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #11 on: October 04, 2018, 01:03:32 AM »
A nice looking engine Mike, will look forward to watching your progress on it. How did you manage to wrestle the castings away from Jo?  :thinking:

Bill


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Offline Jasonb

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #12 on: October 04, 2018, 07:20:47 AM »
Phil, after a quick look at your CAD model the height of the engines ctr line looks like it could be dropped quite easily in two stages.

1. Machine 50% of the pad that the cylinder sits on away looks like about 1/16" could be gained that way.

2. There looks to a plenty of metal on the bottom of the cylinder castings that is not doing anything so material could be removed from here to lower the cylinder until it lines up with the height of the cleaned up bearing pedestals.

Offline pgp001

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #13 on: October 04, 2018, 08:12:37 AM »
Jason

As per your PM, I have just sent my 3D models to you so you can have a play around with them.
This will be a long term project for me, so no rush to sort out the drawings.

I really need to get going on Agnes again, not touched it for months again  :-[

Phil

Offline Jasonb

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Re: Clarkson Twin Horizontal Steam Engine
« Reply #14 on: October 04, 2018, 08:26:30 AM »
Don't worry, the workshop season is just getting started :)

For those with these castings can I ask if any of you have drawings from Blackgates? I was wondering if they now just supply copies of the old Clarkson drawing which is what I have or if they have updated the drawings and possibly corrected these issues?