Topic: Jerry C starts building a Stuart Twin Launch Engine from castings. (Read 43501 times)

Jerry C · « **on:** October 23, 2020, 11:24:30 am »

My second steam launch is almost finished so I thought I’d get ahead of the game and ordered a Stuart twin launch engine casting set. As I type it is on its way from the UK via FedEx. Milling attachment, BA tap and die set and four jaw chuck also coming. Saving up for a small rotary table and chuck. Annoying really as I’ve got them all in UK care of my nephew Ben as I gave them to him in return for his lone of his Peatol lathe. Need something to do or I’ll go mad stuck in Canberra for another 6 months. I’ve always wanted one of these but you can’t buy them ready made so only way is to make one myself. Glued to YouTube learning atm.

Jerry C.

ooyah/2 · « **Reply #1 on:** October 23, 2020, 09:04:14 pm »

Hi Jerry,
Do you think that a Peatol lathe will handle such a big lump of an engine.
If you look up the late Mick Browns thread of his Wide a Wake build he has shown picks of the Stuart launch build on this forum.

WIDE-A-WAKE LAUNCH FOR STUART TWIN ENGINE
« on: May 31, 2011, 04:12:15 PM »

This will give you some idea of its size.

George.

ooyah/2 · « **Reply #2 on:** October 23, 2020, 10:33:10 pm »

Hi Jerry,
Sorry but I gave you the wrong thread, so here is the link to Mick's Launch engine build which should be of help to you.

https://www.modelboatmayhem.co.uk/forum/index.php/topic,28450.0.html

George.

Jerry C · « **Reply #3 on:** October 24, 2020, 12:04:25 am »

Hi George, thanks for all that. I’m using a Chinese mini lathe. Quite a few built with these. Where there’s a will etc.. looking forward to tips from you. Hope you’re keeping well.
Jerry C.

tghsmith · « **Reply #4 on:** October 24, 2020, 02:30:41 pm »

this should be great to watch, at least you don't have deal with large bore on the compound twin, If you don't have one already the first thing I would make is a simple tapping fixture,, the second thing is make sure you have 5 and 7BA taps in HSS, the number of holes is amazing. Stuart is posting that both twins will be available in pre-machined and completed engines in the near future,(thinking that the prices might be on the high side) look over all the parts well when the kit arrives,, my smaller piston rings were on the crappy side of things,, stuart did replace when I sent them a close up photo.. Keith Appleton has a youtube video series on rebuilding a twin, lots of good info.. my crazy is using a Stuart compound block and a few other kit parts.. https://www.rcgroups.com/forums/showthread.php?3018430-US-navy-28ft-steam-cutter

Jerry C · « **Reply #5 on:** October 25, 2020, 12:20:46 am »

tghsmith(can’t keep calling you that Smudge). Thanks for that. I watched the whole series yesterday in fact, taking notes. Also “Blondihacks” is quite informative on techniques and stuff. I’ve got a full set of BA taps and dies coming from China in a sampan. Already made tapping guides. Missing my borrowed Zeus Tables but ok at trigonometry. Next thing on the list is rotary table and chuck. I’ve got one already but it’s in UK.
Jerry C.

Jerry C · « **Reply #6 on:** October 25, 2020, 01:44:53 am »

I’ve just read through Patternmakers build of this engine and it ended abruptly when he died. The first person I followed and inspired me to build “Wear” also died on the third row of planking. It made me think how lucky we are to be able to live on and pass on our skills and inspire others through Mayhem when we “cross the bar”. It’s also a little concerting!
Look after yourselves, just saying.
Jerry.

KNO3 · « **Reply #7 on:** October 25, 2020, 08:28:14 pm »

This should be an interesting project, will follow.

Jerry C · « **Reply #8 on:** November 09, 2020, 11:46:57 am »

The castings from Stuart arrived in good order on Friday via TNT. We’ve been to the seaside(Ulladulla) so nothing done over the weekend. I made a start today, pouring over the plans, making notes, finding what’s what. There are no instructions, pictures or advice. Just a set of plans. I sheet is for the non reversible engine and a smaller sheet showing the differences when adding Stevenson’s reversing gear. All you get are the castings and fastenings, no barstock,copper pipe, no stainless steel for columns piston rods and valve spindles. Aside from the concentric block castings and a concentric straps and rod castings everything els is diy. I spent most of today fettling the castings on my belt sander, grinding off the flash and where possible bringing them close to size as per plans.

Once I’d finished fettling I fitted the new 3” independent 4 jaw Chuck and took 55 thou off the base of the cylinder casting. This is half what’s needed to bring to size and centred on the steam ports so they’ll end up centred on the block. I’ve not turned any cast iron before and as I’d cut through the hard skin it cut very easily using only 10 thou cuts and ending with a 5 thou polish. That was it for today so tomorrow will flip the part in the chuck and repeat. That’ll be the height of the cylinder block sorted next will be the length. For that I’m going to use the little milling attachment, £35 from India on eBay. Only problem with it is no vice on it and can’t find any thing that’ll suit so I’m looking at making a pallet which I can bolt to the vertical slide with 4 bolts and T-nuts. I can then st the mill up sideways on with the cylinder block bolted through the cylinders and then I can mill both port faces bringing it to size.

Then I’ll have a think about exhausts and inlet manifolds and drilling for the support columns, threading for drain cocks and cladding not to mention valve chests and covers.
Jerry C.

derekwarner · « **Reply #9 on:** November 09, 2020, 12:51:44 pm »

Evening Jerry.......you sure don't mess about do you!

......so will be watching on each day as usual............

Does your new smaller lathe mave metric graduations? if so will you be converting the drawings from inches to mm as a whole?

Derek ........[bogged down with Covid-19 Rules & regulations

for Live Steamers]

Mark T · « **Reply #10 on:** November 09, 2020, 04:58:03 pm »

Nice start Jerry keep the updates coming

Jerry C · « **Reply #11 on:** November 10, 2020, 07:03:24 am »

Thanks Mark, Derek, I’ve wanted one of these since I was a lad. I needed something to do during our next 6 months internment or I’d go mad. Perfect excuse/ reason to fork out the cash. This Mini lathe is a fair bit larger than the Taig/Peatol I used before. People have built this engine on Taigs so no worries with this Chinese job. The Taig is imperial being American. This one is also Imperial but I’m happy either metric or imp. Saw some 1/4”x 35mm bolts in Bunnings a few minutes ago!
Today I topped, bottomed and double ended the cylinder block to general sizes. The port channels were blocked with sand and the tried and tested method of using a paper clip to clear them out proved impossible as every draw we pulled out and emptied was paper clipless. Never seen the like in all my days, there’s ALWAYS a paper clip. Did however find a safety pin which was pursuaded to follow the wiggly channels from faces to bores. They appear to be passing evenly, that’s when I got a gob full of grit, it’ll be with me for days.
I put the cylinder block to one side and loaded the base casting into the 4 jaw chuck and cleaned off top and bottom before bringing to specified height. Tomorrow I’m going to have to use the milling attachment to face of the ends then using the rear centre mounting lug as a datum I can drill all the holes for the columns and crankshaft bearing cap holes.

Jerry C.

ooyah/2 · « **Reply #12 on:** November 10, 2020, 09:38:32 pm »

Hi Jerry,
You might consider what I did on my launch engine base plate, I was concerned about the bottom half of the main shaft bearings being part of the base plate casting.
I thought that it was very bad practice and poor engineering thought, i.e. what happens in the future if the bearings ware, how do you take up the slack in the bottom half of the bearings, so I decided to make split bearing blocks by facing the top bearing covers and soft soldering them to a peace of Gun metal, facing them to size and marking off the hole centres leaving 1/8" of metal from the bottom of the bearing to the top of the base casting always remembering to add on to the piston rods, the columns, the slide valve rods, the difference created by doing as I did.

I remember Mick having long thoughts on how to machine the base casting to give a clean Finnish to the bearing and as he didn't have a long reamer to bore and ream on the same fixing he used a ball nosed cutter and finished off by file and emery cloth, can't remember what sort of Finnish he achieved but I do know that he spent hours running in with oil and [size=78%]"T" cut.[/size]

Her is a few pics of my method.

Regards
George.

tghsmith · « **Reply #13 on:** November 10, 2020, 10:48:17 pm »

I used this page for info on methods,, most of it should apply to the twin also..
http://compound.modelengines.info/

ooyah/2 · « **Reply #14 on:** November 10, 2020, 11:41:46 pm »

Hi T.G.

This link will help Jerry a lot, I wish that I had known it when I built my engine, especially the base machining to take the main shaft,
Still I think I would still have gone the way that I did as during my apprenticeship all of the large shafts that had to be serviced had shell bearings and not any of them that had a base plate used the base plate as the bottom bearing.
It's a very good site and a very experienced machinist.
Thanks for the link .
Where were you when I needed you ??

George.

derekwarner · « **Reply #15 on:** November 11, 2020, 03:24:02 am »

That is an excellent alternative solution path you went on for the bottom end bearings George

the detailed photography images are also superb for a reference to new builders etc

Derek

KNO3 · « **Reply #16 on:** November 11, 2020, 08:54:20 am »

Quote from: ooyah/2 on November 10, 2020, 09:38:32 pm

Hi Jerry,
You might consider what I did on my launch engine base plate, I was concerned about the bottom half of the main shaft bearings being part of the base plate casting.
I thought that it was very bad practice and poor engineering thought, i.e. what happens in the future if the bearings ware, how do you take up the slack in the bottom half of the bearings, so I decided to make split bearing blocks by facing the top bearing covers and soft soldering them to a peace of Gun metal, facing them to size and marking off the hole centres leaving 1/8" of metal from the bottom of the bearing to the top of the base casting always remembering to add on to the piston rods, the columns, the slide valve rods, the difference created by doing as I did.

I remember Mick having long thoughts on how to machine the base casting to give a clean Finnish to the bearing and as he didn't have a long reamer to bore and ream on the same fixing he used a ball nosed cutter and finished off by file and emery cloth, can't remember what sort of Finnish he achieved but I do know that he spent hours running in with oil and [size=78%]"T" cut.[/size]

Her is a few pics of my method.

Regards
George.

Hi George, if your concern was wear, why didn't you simply add some (later replaceable) bearing sleeves and keep the original configuration?

ooyah/2 · « **Reply #17 on:** November 11, 2020, 09:48:02 am »

Not ware but aesthetics, and it was so much easier to make the bearing blocks as shown
and no special tools were required to make them

George.

Jerry C · « **Reply #18 on:** November 11, 2020, 11:14:06 pm »

Hi George, I agree with what you say, however, I’m going to build this one as per plans. The reason is in honesty I can’t really afford one of these but have to do something to stop me going mad stuck here in Oz. Second, Stuart are going to put this engine in their catalogue shortly so it will be possible to buy one so my plan is to offload this one and buy another set thus getting it for free.
TGH thank you so much for that link. Missed the whole Vuelta España watching it last night. All my questions answered and he did it all with a Taig. I don’t have a mill, only a vertical slide but I’m sure I’ll manage. Iv actually started a journal on this build with all the finer details to be recorded so I can blitz the second one. Each numbered section on the drawings has it’s own chapter with details of what to buy, drill, tap, die and reamer sizes and how I did it. Nice hardback for the future.
Jerry C.

ooyah/2 · « **Reply #19 on:** November 12, 2020, 12:01:41 pm »

Hi Jerry,
Not to worry I wasn't saying that you should do as I did but just another method to make the bottom bearings.
I think that if I had known of the link that T.G. sent I may have gone down that road but another consideration that I had was that I didn't quite know how to do the 5/16" groove to take the main shaft and as I had a background servicing multiple diametre shafts running on blocks with replaceable brass shells that was the way that I went.
I still maintain that Stuarts method is bad practice and it has never been changed since the 1930's, now I know that in most large steam engines, boats and mills, the base plate casting had removable shells and needed to use small hydraulic jacks to lift the main shaft a few thousands to slip the bottom bearing to be replaced that I do know as I been there and done that, but bad practice to use the main base casting as the bearing surface.

George

Jerry C · « **Reply #20 on:** November 13, 2020, 08:44:38 am »

I’ve completed the eccentric sheaves. The first one took me a day and a quarter including interruptions. The second took a day but I’m pleased to report they are perfick, down to 0.0005” and no disasters. I’ve decided not to include the details in this thread as I’m using the thread posted earlier on the compound version unless my method deviates from it.

I never realised how dirty this cast iron is, I don’t think my fingers will ever be clean again! I’m also suffering from a stonking headache caused I think by the distortion caused by wearing safety specks over my glasses. Might have a day off tomorrow as my daughter has two softball games tomorrow so a nice day out.
Jerry C.

Jerry C · « **Reply #21 on:** November 15, 2020, 10:20:53 am »

Today I machined the top cylinder covers. The process was made especially difficult due to on having no casting stubs to get hold of in the chuck. Earlier sets of castings had stubs to top and bottom, these had neither. Nothing for it but to grip the edge with the base towards the chuck. Too big to fit in the inside jaws so swapped to the outside jaws. Parts not wide enough to be gripped by the outer step so fitted them in the second step. This meant I had to be creative with my choice of the best tool. I had to grind a fair bit off to stop it fouling on the outer part of the jaws. I cleaned up the top surface up to the dome then scribed a faint bolt circle for later. Then I removed the part and I blued up the outer edge and using my callipers scribed the edge thickness. Reversed the part in the chuck still gripping on the edge but loosely then carefully tapped the part into the jaws until the scribed mark was as level with each jaw as I could make it by eye. I nipped up the jaws and faced the lower surface. Then I turned down the outer edge to size. Then I turned down the base to the required thickness leaving the 1” diameter centre part. This bit that fits into the cylinder was now much longer than required but allowed the jaws to get a good grip on. Now at last I could turn the outer diameter of the part to 1 1/2” and square to the bottom surface. Set my dial gauge on the top surface where the studs go and it was near enough but gave it a quick skim. Reverse part in chuck and removed the excess on the stub and all done. Happy. Repeated the process on the second cover. Dimensions good but finish needs some work. Must get some Scotchbrite.

Jerry C.

Mark T · « **Reply #22 on:** November 15, 2020, 02:36:03 pm »

Thats tricky work Jerry but well executed using what you've got - top job

frazer heslop · « **Reply #23 on:** November 15, 2020, 04:10:14 pm »

For cylinder cover just glue them into a simple jig (pot chuck) super glue will do the job and a sharp tap will release the glue

Jerry C · « **Reply #24 on:** November 15, 2020, 10:12:59 pm »

Thanks for that Frazer, I’ll try that when I do the bottom covers.
Jerry C.

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Author Topic: Jerry C starts building a Stuart Twin Launch Engine from castings. (Read 43501 times)