Author Topic: Stuart S50  (Read 4751 times)

Offline samc88

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Stuart S50
« on: December 06, 2021, 11:13:39 PM »
New project incoming, recently acquired a Stuart s50 kit from a friend, and since I'm in the process of upgrading my small mill with a DRO this seems a nice thing to make to get used to it. As a side note this is the Stuart engine I've always wanted to make but lack of a mill before meant I went for the 10V instead. This obviously means my loco project is on hold for a little while but its not abandoned. This should keep certain stationary engine casting fans happy too

I have a plan to make it more scale looking by removing the cast in bolts with real ones and instead of using bolts for the engine fasteners I'll use studs with one size smaller BA nuts (since I have a packet of them already and they look really good). If it goes well Id also like to have a go at some rope grooves too in the flywheel (I've got a spare flywheel if it doesn't go to plan).

Got some steel coming to finish the DRO on Thursday and a couple of bits for this engine coming this week so hopefully be able to make a start over the weekend.





« Last Edit: December 06, 2021, 11:42:15 PM by samc88 »

Offline propforward

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Re: Stuart S50
« Reply #1 on: December 06, 2021, 11:18:35 PM »
Very nice, look forward to seeing that progress. Do you have any posts on your DRO install? I remember you mentioning you were going to add that feature - it's a game changer, love the DRO on my mill. I always enjoy seeing peoples solutions to those kinds of installs - I am going to put one on my lathe soon.
Stuart

Forging ahead regardless.

Offline samc88

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Re: Stuart S50
« Reply #2 on: December 06, 2021, 11:20:38 PM »
Very nice, look forward to seeing that progress. Do you have any posts on your DRO install? I always enjoy seeing peoples solutions to those kinds of installs - I am going to put one on my lathe soon.
I'll take a few pictures once I'm done, I've managed to do it without tapping anything on the machine which I'm happy with, taken a bit of head scratching as everything came with no instructions being a bit of an ebay special all the way from China. Looks good value for money though



« Last Edit: December 06, 2021, 11:42:00 PM by samc88 »

Offline jeff l

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Re: Stuart S50
« Reply #3 on: December 07, 2021, 06:31:54 AM »
I built the S-50 many years ago I also milled off the cast in bolt heads and replaced them with the correct size bolts , the model looks much better with this modification .

Offline samc88

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Re: Stuart S50
« Reply #4 on: December 12, 2021, 09:59:40 PM »
As promised, I made a start this weekend.

The base was first tidied up with a selection of files before pressing the granite chopping board/ surface plate into action with some wet and dry to flatten the bottom. Only took about an hour to take the rock out and get full contact all the way around. When done the relevant heights were all marked out with the height gauge.

After watching Ades workshop on youtube build his S50 I bought a piece of aluminium to act as a build plate for my engine, this was mounted on the mill and clamped down after being clocked in true. Once this was done the engine base was clamped to the plate, truing it up using a DTI on the crosshead rails to get an average being a casting.

Machining wise, the first thing to be done was to drill and tap for the mounting screws which was done to 4BA. Once that was done, I spot faced each mount one at a time and bolted the base down.

Next up was machining the cylinder bolting face, the quill DRO was excellent for this, touched the 8mm milling cutter onto the aluminium and set the DRO to 0, then machined it down until it read 1.5". Came out bang on when checked with my depth gauge so its reassuring my cheap DRO works properly. Similarly the crosshead rails were then machined to the correct height before machining the sides slightly to give me a reference surface if i have to clock it in again for some reason.

Finally i took off the false bolt heads in preparation for drilling and tapping for real studs and nuts which should look much nicer

 


















Offline scc

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Re: Stuart S50
« Reply #5 on: December 13, 2021, 04:47:47 PM »
 :ThumbsUp: :popcorn:           Terry

Offline samc88

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Re: Stuart S50
« Reply #6 on: December 14, 2021, 08:54:50 PM »
Had my first go at coordinate drilling using the new DRO today, it makes life a lot easier. Also used ny wiggler/ edge finder for the first time too, its really effective.

Firstly I found my datum point using the small wiggler (crankshaft centreline and the crosshead centre line).

Next I drilled the cylinder mounting holes 7BA clearance and then drilled and tapped the crosshead rails 7BA. The drawing doesnt quite match the casting but Ive left the hole positions as drawn as I've seen a few others built and it doesnt seem to cause an issue down the line when fitting the cylinder, plus you cant see them so not really a visual issue either when finished.

Next operation is to mill things to the correct width and drill and tap for the decorative bolts, Im trying to do as much as possible before disturbing the set up to drill and ream the crankshaft bore.













Offline simplyloco

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Re: Stuart S50
« Reply #7 on: December 14, 2021, 09:04:20 PM »
Very good, neat work. We didn't have 'wigglers' when I learnt my stuff, relying on feeler gauges and cigarette papers instead! I wouldn't be without my gadget now, especially when using the 'Centre Find' facility on the Easson DRO! I use the 0.10 disc mainly.
John

Offline samc88

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Re: Stuart S50
« Reply #8 on: December 14, 2021, 09:20:17 PM »
Very good, neat work. We didn't have 'wigglers' when I learnt my stuff, relying on feeler gauges and cigarette papers instead! I wouldn't be without my gadget now, especially when using the 'Centre Find' facility on the Easson DRO! I use the 0.10 disc mainly.
John

Thank you, its a long way off your beam engine though! Ive had this wiggler for ages, I think my brother bought it for me one christmas but I felt it too much of a faff to use when you just have to count the handwheels so did as you did with feeler gauges. Really enjoying myself getting used to the DRO, definitely a worthwhile upgrade

Offline samc88

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Re: Stuart S50
« Reply #9 on: December 15, 2021, 07:08:00 PM »
This evenings job was to drill and tap the 7ba holes for the decorative studs that will be going in place of the kits cast bolt heads.

 I discovered that a 4BA screw head was the same size as the round pads so I turned the dome flat in the lathe and used it as a pointer, once in the correct position I drilled and tapped 7BA. A gauge pin would be more solid but i would have to keep changing chucks which would get tiring after a while.

The bolts for the crankshaft pedestals were done by eye, placing an 8BA nut on top and positioning the drill until the position of the nut looked right (8BA as Im going for one size smaller nuts). Quite pleased with how this came out.

 













Offline samc88

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Re: Stuart S50
« Reply #10 on: December 16, 2021, 04:41:45 PM »
Finishing the base.

First the sides were machined to the required width in the drawing using an 11mm ball nose cutter. It doesnt have to go down this far but thought i would to better match the casting.

Next up was the crankshaft bore. I dont have an angle plate but do have my old vertical slide. The base plate was clamped to this and then indicated to ensure it was lined up correctly.

Once that was done I used the wiggler to find the centre of the crankshaft, i first found one of the 7ba holes in the crosshead rail and worked back from that, similarly i set a datum point from the aluminium plate to give me the correct height if 1 15/16".

I noticed the kit doesnt have any provision for bearings which is a shame so Im going to make some out of bronze since i have some in stock. Therefore rather than making the holes 1/4" I enlarged them to 5/16' (as i have a reamer that size)

Next operation will be to make the crank bearings














Offline Grateful Ted

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Re: Stuart S50
« Reply #11 on: December 16, 2021, 05:51:58 PM »
I like your crank bearing idea.
Iíve been thinking of retro-fitting my PM#3 with crank mains bearings.
Probably wontí as it runs great as is, & iím In the middle of a PM#5 build now & itís proving to be a wee bit harder (for me) than the #3 was.
Iím enjoying your build!

Offline samc88

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Re: Stuart S50
« Reply #12 on: December 16, 2021, 08:37:21 PM »
I like your crank bearing idea.
Iíve been thinking of retro-fitting my PM#3 with crank mains bearings.
Probably wontí as it runs great as is, & iím In the middle of a PM#5 build now & itís proving to be a wee bit harder (for me) than the #3 was.
Iím enjoying your build!
Thanks Ted, got to say Im enjoying this one more than the 10V I did a few years ago, i think having a proper set up helps a lot, i only had a vertical slide when i did that

Sent from my SM-A127F using Tapatalk


Offline samc88

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Re: Stuart S50
« Reply #13 on: December 16, 2021, 08:53:30 PM »
Crankshaft bushes.

The drawings would have you just put a hole straight in the cast iron but since i have some bronze to hand i decided to make some bushes. First the holes in the casting were measured with my small hole gauges, before the bronze was then turned to the right OD (.5 a thou over) and then parted off.

I didnt want to hammer the bushes in and its an awkward shape to hold in the vice with risk of damage so made a puller from an M6 bolt and a couple of nuts which worked really well, pulled the bushes in nicely. Once pressed in I passed the reamer through.

The supplied crankshaft steel is 3 thou undersize when measured so rattled a bit in the bushes. I did remember that I had some 1/4" silver steel which is bang on size which Ill be using instead for the crankshaft.

All thats left on this now is to drill the oil holes

I'm having to use attachments from now on as I've reached my upload limit on tapatalk without paying for it, they're all resized though

« Last Edit: December 16, 2021, 08:57:37 PM by samc88 »

Offline samc88

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Re: Stuart S50
« Reply #14 on: December 17, 2021, 08:52:11 PM »
Crankshaft and crankweb.

Crankshaft is pretty simple, just needs one end threaded 2BA and then cut to length. I did add a small mark with a centre drill though like full size ones have when they got made.

Crankweb starts off as 1.5" steel which I faced using a round nose tool to give me the radius on the centre boss. This was then drilled and tapped 2BA before parting off/ cutting off with a hacksaw.

This was then mounted on the shaft allowing me to turn to final thickness. Once done it was time for some marking out using my v block and height gauge, letting me mark the corner points of the angle for milling down. At the same time i marked the hole for the crankpin.

This was then milled down to size, mounted on the crankshaft with loctite and given a polish. I think ill carry on working down the crank assembly and make the eccentric sheave next