Stuart S50 stationary engine.

[mechman48]

Hi all
Started on my S50 engine past couple of weeks; looks to be more interesting than the 'Progress' I have just completed. Started off fettling the base, flywheel & other sundry bits, amazing the amount of sand that comes out of the cylinder ports, mind you this kit is one of 3 that I'd got for my birthday some 4 years ago so they weren't the best of castings, did speak to Stuarts rep at Doncaster last year & he commented that they've changed casting supplier who now produce better quality castings.

pic 1... Major components...

pic 2...fettled base

pic 3... machining base...

pic 4... Drill & tap base...

pics 5/6/7/8/... set up & machining cylinder flange/ bore...

[John Rudd]

George, looking good so far, up to your usual build standard...

Is that a saddle stop I see in the last picture on your WM250? Got any plans? ( assuming it will fit my SPG clone)

[mechman48]

Hi John
Did have a simple dwg at one time, whether I've still got it is another question... will have a look on my files & see if I kept it otherwise it would be a quick hand drawn sketch... I'm not conversant with AutoCAD etc, have just downloaded 'Sketch Up' to have a go   

[krv3000]

oooo brill

[mechman48]

George, looking good so far, up to your usual build standard...

Is that a saddle stop I see in the last picture on your WM250? Got any plans? ( assuming it will fit my SPG clone)

Have been out to garage & done a sketch for you... the old fashioned way... & if it's of any use to others ... feel free to use it.

Also close up pic...

[tom osselton]

Thanks for posting that!

[mechman48]

Follow up on the S50 stationary engine...Drilling & tapping the cylinder fixing points... drilling the steam ports... +additional pic of home made tapping stand.

[mechman48]

Bit more done...

Piston, piston rod, cylinder covers, gland nut, crank & crankpin... slowly, slowly catchee monkey... ...

[mechman48]

... onward & upward... a bit more for my S50 engine...
also filed to size, cleaned up & lapped the valve / face, made the valve adjuster nut, had 3 attempts at that as couldn't get the 7BA tapped hole central & square     didn't get any pics of that ...yet   

[mechman48]

S50 again... attempted to mark off the valve chest cover this week, got the scribe lines marked ok but when it came to centre popping the hole positions, not a lot happening, apart from my centre punch point being flattened... yep! chilled cast iron   , dried drilling, one 2.5 drill later...there was no way that drill would ever get through that skin, so what to do?. A quick stir up of the old grey matter brought up...  ... normalise / temper it, not having a Bar-b-Q going ... here in the UK...  ! ... & not having enough MAPP gas to have a prolonged saturation I wrapped it in aluminium foil, stuck it in the kitchen oven, set at highest temp. 250*C & let it soak for a couple of hrs & then let it cool naturally overnight, seemed to do the trick albeit not 'soft' it was drillable. pics show cover after soaking overnight... still shows dark straw colour hence not 'soft' but as said 'drillable'. So for those with the S50 Kit, or any other casting kit for that matter, check out castings for chilled areas ... (please excuse the un-intentional granny & eggs intimation).  p.s. carefully reground centre punch so no need to re-temper point.

[mechman48]

S50 update... assembled the bits 'n' bobs made so far, starting to look like an engine... 

[mechman48]

Further progress, onward & upward as the saying goes...

Eccentric rod fork end;
Machined crosshead, thought I had taken pic but ... 
Machining conrod ... couldn't be arsed to change from 3 jaw to 4 jaw chuck so made up a split bushing to hold conrod, ran as true as could be...     
Marked out the conrod for crank pin & gudgeon pin drilling, (actually marked on the other side).
Partial assembly of conrod...
One of the trial assembly views ( overhead ) looks like the crank shaft is out of true...  ... rest assured it is not,     it is the camera angle.

[paulmo101]

Looks great Well done

[mechman48]

Did a bit more yesterday... machined the flywheel

OD... Reamed... nice smooth fit ( for once, ...Oooh you are awful matron )

[SwarfnStuff]

Hey, just how do you ream the OD of something?  He he, I know it's just a typo OR I'm completely lost here.
   Good post to follow,
Thanks for posting Mechman.
 John B

[mechman48]

Hey, just how do you ream the OD of something?  He he, I know it's just a typo OR I'm completely lost here.
   Good post to follow,
Thanks for posting Mechman.
 John B

Yeah, typical typo when you abbreviate sentences, but I think you sussed it out   

George.

[mechman48]

Update on the S50...

Machined up the eccentric & the eccentric strap; the eccentric offset was going to be done in the 4 jaw chuck but found that by judicially making up a packing piece & placing it under one jaw on the 3 jaw chuck, the throw could be set up quite accurately not 100% perfect but as near as makes very little difference from my past experiences.

The strap was centered up by using my tool centre height surface gauge to mark out radial lines & where they intersected was the centre of the blank, fortunately for me all the lines intersected quite nicely but if not where the lines leave a miniscule gap the centre can be located by eye well enough, maybe plus the use of a loupe for those with elderly eyesight, (which includes me!) for all intents & purposes. Next step just need to machine the strap to width, drill & tap for locking bolt & split. the eccentric needs to have the grub screw location drilled & tapped then all to be cleaned up & polished. The last pic is the start of preparation for paint up, etch primer & first coat on the cylinder assembly & flywheel... yeh I know... its obvious but... 

I realise that there are many hobbyist out there that are capable of & have done many superb & complicated models so some readers may find this write up boring ( Yawn ) & some may say 'well I did it this/that way' but in the words of 'ol blue eyes... 'I did it my way', the intent is that, hopefully, newbies or those with very little experience will find it of some help, so I will continue to write this up, along with pics...

[DMIOM]

..... fortunately for me all the lines intersected quite nicely but if not where the lines leave a miniscule gap the centre can be located by eye well enough.....

Known as the 'cocked hat' by navigators plotting fixes.

Dave

[SwarfnStuff]

Yeah, Please keep going George. I'm learning stuff here along with many others I would guess.
    Besides, it's a good write up.      

John B

[mechman48]

S50  ... A note of caution, before machining the eccentric strap machine the strap down to dimensions for the thickness before boring out, I didn't & when nipping up in the mill vice it squeezed 'out of round'     . why I thought of using the mill at that point I cannot for the life of me remember! should of used a mandrel in the first place... brain fade no doubt      Rather than make a complete new strap I ended up pressing a 5/8" silver steel (drill rod) mandrel through to get the bore back to round... not 100% but as near as dammit, then machined to thickness, we'll see how it turns out when fitted & turned over 

pics show assembly, need to clean up & polish...

[mechman48]

Trying to update but keep getting 'Error 500, can't display this webpage' message any ideas?

[mechman48]

Tried again... anyone help or having same bother?

[mechman48]

Tried again... anyone help or having same bother?

Another try at updating...

Eccentric & strap...

Eccentric, strap, crank, crosshead, piston, pre build assembly...

[mechman48]

S50 

Spray painted the castings with top coat auto spray; assembled all parts to establish where any tight spots maybe prior to trial run...  need to clean up valve chest face, set up approximate valve timing, fit joint then we'll see how she runs... possibly clad the cylinder with stained wood...    make display base... trial run... 

[SwarfnStuff]

Oh, this is looking gooderer and gooderer. Thanks for posting Mechman.

John B