Author Topic: AOGís version of the Stuart S50 Engine  (Read 1591 times)

Offline AOG

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AOGís version of the Stuart S50 Engine
« on: September 15, 2018, 11:27:18 PM »
Iím sitting here in my living room with the house buttoned up waiting for a hurricane to hit so I thought I would post the start of my next build. I am making a Stuart S50. I started by sanding the base until it sat flat on the surface plate.



Then the mounting feet were spot faced.



The casting was kind of rusty so I cleaned it up with some navel jelly. The casting was primed to prevent further rusting and the mounting holes drilled.



The base casting was mounted to a tooling plate and the various flats milled.



Next the bearing stands were cleaned up and the oil holes spot drilled to be the reference point for the centerline of bearing supports.



The base casting was flipped on itís side and leveled in relation to the vise.



The bearing supports were drilled and reamed to take a 3/8 Bronze bearing.



The bearings were center drilled and taken to size.



Then they were pressed into the base casting.

.

Then the base was placed back on the mill and the bearings were drilled and reamed.



The last operation was to drill and tap the top of the supports to take some PMR oilers.



Thatís it for now. Till next time

Tony


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Offline b.lindsey

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Re: AOGís version of the Stuart S50 Engine
« Reply #1 on: September 15, 2018, 11:43:02 PM »
Great start Tony!! Are you feeling effects of the storm yet. We have just had a slow steady rain today. Very little wind here but I am well inland compared to Savannah.

Bill

Offline 10KPete

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Re: AOGís version of the Stuart S50 Engine
« Reply #2 on: September 15, 2018, 11:43:52 PM »
Good start! I hope the storm misses you...

Pete
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Offline zeeprogrammer

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Re: AOGís version of the Stuart S50 Engine
« Reply #3 on: September 16, 2018, 01:01:33 AM »
I had no idea where you were. I hope all goes well.

I look forward to your new build.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #4 on: September 16, 2018, 02:35:34 AM »
Thanks guys, I think Iím going to get lucky this time. The storm is tracking further north then expected. Hopefully if everything goes well, I can get the garage reconfigured into shop mode tomorrow and get back to work on this project.

Tony

Offline bent

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Re: AOGís version of the Stuart S50 Engine
« Reply #5 on: September 17, 2018, 06:37:58 PM »
Nice start, Tony.  Gotta get my garage reconfigured too, now that the rain has started...

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #6 on: September 23, 2018, 07:17:41 PM »
My shop time this weekend was something of a disaster. My original intent was to start work on the cylinder casting. Letís just say that after destroying 3 inserts and crashing my lathe I think that cylinder casting may be better as an AP round then as a cylinder so I ordered another one. After wasting the majority of my shop time on the aforementioned disaster, I decided to make the crankshaft with the time I had left. After truing up the parent stock in the lathe I turned the required boss and drilled and tapped the center of the crank.



The final shape for the crank was marked out and milled.



Then I spot drill the location of the crank pin. To keep it square to the crank, I wonít drill and tap the hole until later.



The crank was parted off from the parent stock and then I threaded the shaft.



The crank was mounted to the shaft. Then the assembly was mounted in the collet chuck and trued up. At that point I discovered that my parting tool had wandered and the crank ended up very thin.



Now that the crank face was true to the shaft I drilled and tapped for the crank pin.



Since the engine isnít going to run under load Iím not worried about the strength of the thin crank but I am concerned about the alignment with the cylinder bore. I decided to make a bronze spacer to correct the geometry. It was drilled and parted off.



So after a weekend worth of work, all I have to show for it is a crankshaft.



Maybe Iíll have better luck next week.

Tony


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Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #7 on: October 04, 2018, 01:30:10 AM »
I got my replacement cylinder casting........ and promptly stuffed it up. Somehow I donít think this is right.



Oh well, time for another ten day wait.

Tony


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Offline jeff l

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Re: AOGís version of the Stuart S50 Engine
« Reply #8 on: October 04, 2018, 03:58:46 AM »
Nice start on the engine , I made this engine years ago and found the cast in bolts unattractive so I milled them off and drilled and tapped them for proper model engineering bolts .The extra work was worth the effort .Jeff

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #9 on: November 01, 2018, 04:14:40 PM »
Ok this build is officially cursed but letís get caught up first. While I was waiting for a replacement cylinder, I decided to make the eccentric and the strap. I started with the strap extrusion.  It was first trued up on the lathe.



Then it was bored out on the mill.



The holes were drilled and the strap was slit.



Then the eccentric itself was made. First it was turned to size and grooved.



The piece was offset and then drilled and turned.



The eccentric was drilled and tapped for a set screw. Then it was parted off.



Here is where we sit today.



Now for the cursed part. I have successfully botched cylinder number 3. At this point I have spent almost as much on cylinder castings and shipping and I did for the whole model. It will take approximately 2 weeks to get another casting but I think this is a sign that I need to get away from model engineering for a while. I donít know when Iíll be back

Tony


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Offline Admiral_dk

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Re: AOGís version of the Stuart S50 Engine
« Reply #10 on: November 01, 2018, 07:28:28 PM »
So sorry to hear that you have those disheartening problems with the cylinder - I hope somebody here can give you some useful advise ....

Best wishes

Per

Online Jo

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Re: AOGís version of the Stuart S50 Engine
« Reply #11 on: November 01, 2018, 07:41:25 PM »
Tony can you let us know what the unintended features were with the cylinders? In case we could come up with some fix its...

That out of line bore could be sleeved  :thinking:

Jo
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Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #12 on: November 01, 2018, 07:42:53 PM »
Itís not so much lack of advice as lack of attention to detail. Thatís the sign that I need to step away for a while until I can spend the time to focus on what Iím doing. I donít have to tell you how dangerous it can be in a shop if your not focused. Right now all I am out is money and time. The last thing I need is to get myself hurt.

Tony

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #13 on: November 01, 2018, 07:57:52 PM »
Tony can you let us know what the unintended features were with the cylinders? In case we could come up with some fix its...

That out of line bore could be sleeved  :thinking:

Jo

So far itís been the armor piercing casting, the misbored cylinder and the last one was too short on three faces and more importantly the drill wandered when drilling one of the ports. It chewed up the inside of the cylinder and damaged the port face when it broke through. Basically Iíve been going through the motions and not really paying attention to what I was doing. As I said before, that is potentially dangerous in the shop and a sign I need to get away from this for a while.

Tony

Online Jo

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Re: AOGís version of the Stuart S50 Engine
« Reply #14 on: November 01, 2018, 08:20:51 PM »
:thinking: Maybe Tony you have three pieces to practise with.


The first one sounds like it has hard spots - chuck it in a fire and leave it in the hot embers for at least 24 hours to cool down. Then test the hard sports with a file.

How far out is the misboring on cylinder 2? It could be sleeved, or rather bore it out a bit more and loctitie in another bit (steel or CI or even bronze/brass) and practise boring in the right place. The trick is to line the bore up using the valve face and the outside of the cylinder - ignore the existing bore.  If you get it right you possibly could have a cylinder to use  :)

The cylinder with three short faces is a little trickier but it all depends on how much shorter they are if it is only 1mm you could probably get away with it. The port face can be recovered by machining the top surface off and adding an additional plate. As the valve chest is to be screwed on you can probably get away with securing it with JB weld  :-X


Don't throw them away, think about what caused the features, then use them to practise on and you never know you might find one is good enough to use, no one will be any the wiser  ;)

Jo
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Offline Gas_mantle

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Re: AOGís version of the Stuart S50 Engine
« Reply #15 on: November 01, 2018, 08:42:40 PM »
Hi Tony,

Sorry to hear you have hit a bad period but please don't give up, I have always followed your build progress with interest and I'm sure many others do also  :)  As well as the highly skilled modellers here there are a lot of less experienced members who learn a lot from 'simpler' builds so your work is a valuable contribution.

In the meantime is it possible to make a temporary cylinder from barstock to at least get your engine running? You can always replace it with a casting later  :)

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #16 on: November 01, 2018, 11:54:09 PM »
Thanks for the encouragement guys. Sorry Jo, unfortunately the culprits have already been sent to sleep with the fishes (sent to the recyclers). I have ordered another cylinder casting from the U.K. That right there is an enforced two week vacation. Weíll see what happens after that. I think I am going to play with my 3D printers for a while. I havenít made a plastic model in ages. Hopefully I can find a model to print and assemble on thingiverse.

Tony

Offline bent

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Re: AOGís version of the Stuart S50 Engine
« Reply #17 on: November 02, 2018, 05:09:13 PM »
What gasmantle said - we learn from our mistakes; note the collective pronouns used there.  I like your build logs, they describe your processes well.  My build logs contain all the warts and wobbles, in hopes those who follow don't repeat my mistakes.  But I get taking a break, I'm doing the same recently, as have had some other stuff taking up my time.  When my head is ready to get back in the game, I will start up model engine building again, as will you I suspect.  Jo, those are some good ideas to put in the notes in the margins of some of my drawings I've been doing...:)

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #18 on: November 20, 2018, 02:04:59 AM »
Itís been a little while and Iím back at it again. The fourth time is the charm. It came came out undersized in a few non critical areas but it will work. Just as a note the pictures are a mishmash from my various attempts to get this done. Letís get to it.  I set up the four jaw and faced one end of the cylinder casting so it would lay flat against the chuck.



Then the casting was flipped and centered on the cored in hole. The casting was bored out to size and the end turned.



Then the cylinder was placed on a mandrill and the other end turned.



The part was placed back in the four jaw and the valve area taken to size.



With the valve face as a reference the other flats were squared up in the mill.



Next the mounting holes were drilled 7BA.



The cylinder ends were notched in preparation for drilling the steam passages.



Hereís where it went south on me (again). On one side I misjudged the angle and ended up missing the valve port. While trying to meet the hole I accidentally drilled through the cylinder wall. I was able to recover by filling in the valve port with JB weld and milling it back out to meet the steam passage. Hopefully this wonít be too big of an issue.



With that out of the way I drilled the exhaust and two of the mounting holes for the cladding. Iíll transfer the other holes from the cladding when itís done.



Next up was to drill the holes for the valve chest mounting studs.



From there I drilled the mounting holes for the cylinder covers. I ended up accidentally breaking through on one side so broke out the JB weld and built up the flange and drilled it again.



With everything drilled I put the casting in my tapping fixture and tapped all of the holes.



All I can say is that Iím glad thatís done. Itís been quite a while since I had a part fight me this badly. Iíll be back on this project after I get back from Thanksgiving.

Till next time

Tony



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Offline bwal

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Re: AOGís version of the Stuart S50 Engine
« Reply #19 on: November 21, 2018, 08:42:39 AM »
Hi,

Good work, I'm following along with much interest. Definitely learning some new tricks. I keep referring back to your ST build before I start work on my one.  Any chance you've made a 10V or are going to make one in the future?

Ben

Offline b.lindsey

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Re: AOGís version of the Stuart S50 Engine
« Reply #20 on: November 21, 2018, 11:11:05 PM »
Happy to see you got over the rough patch Tony. Now all you have to worry about is eating too much on Thanksgiving  ;), if there is such a thing.

Bill

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #21 on: November 22, 2018, 12:58:37 AM »
Thanks Bill, Iíll try to avoid needing the wheelbarrow after eating. Ben I have a 10v on the ďto doĒ list but not for a while.

Tony

Offline Gas_mantle

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Re: AOGís version of the Stuart S50 Engine
« Reply #22 on: November 22, 2018, 04:18:49 PM »
Glad to see you are back in the saddle Tony, despite a few glitches I'm sure your engine will turn out fine.  :)

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #23 on: December 03, 2018, 03:12:46 PM »
I got some more work done this weekend. I managed to get the cylinder covers done. The first one I did was the top cover. I turned it to diameter and then turned the face.



Then it was parted off and the shoulder turned.



Lastly it was over to the mill where I drilled the mounting holes.



Then I started on the other cover. I turn the part to diameter and drilled the end.



I went to tap the end when I realized I looked at the wrong column of my thread table and drilled it clearance size instead of tapping size. I ended up going up one ME thread size. Then I flipped the part and turned the register.



Then back to the mill to drill the mounting holes.



Iíll leave you with a current family shot.



Till next time

Tony


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Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #24 on: December 06, 2018, 09:37:20 PM »
Itís time for a quick mini update. I managed to get the piston assembly completed so letís get started. First I turned the piston blank down to about .040 ( about 1 mm ) oversized. From experience, I have found that threaded pistons usually donít end up concentric to the rod. As a result I left it oversized for later clean up.



Then I drilled and tapped the end for the piston rod.



The piston was parted off and put to the side for now. Next I cut a piece of steel rod and threaded both ends to be the piston rod.



The piston was screwed onto the rod with some thread retainer to hold it. When that had cured the assembly was placed in the collet chuck and turned concentric and then to size. Then I put in a few oil grooves completing the part.



Till next time.

Tony


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Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #25 on: December 10, 2018, 05:26:05 PM »
More good progress this weekend. That being said, I am extremely disappointed in the quality of the castings from Stuart. As of right now, every piece of cast iron in this kit with the exception of the base casting has been chilled. I have spent almost as much in replacing blunted and broken tooling as I did on the model itself. The next part, the valve chest was no exception. The good news is that I have built enough of Elmerís engines that I could fabricate a replacement from some brass I had in my come in handy pile. First is squared up the ends in the mill and then turned the valve stem round in the lathe.



Next it was drilled and tapped. I only drilled it halfway to prevent wandering. I will do the final drilling after I hollow out the valve chest.



Then the part was flipped and recentered in he four jaw. The far end was turned to size and rounded over with my ball turner.



Next it was over to the mill where the valve chest was taken to size.



The cavity was marked out based on the casting dimensions and chain drilled.



Then the inside was cleaned up with an end mill.



The last operation was to drill the end using the existing hole as a drill guide.



After some quality filing time the valve chest was complete. Since the valve on this engine comes with the kit, I cut, drilled, and tapped the valve nut.



Then I did some clean up on the valve itself to get it to fit.



The last part in this update was the valve chest cover. Like the other iron castings it was chilled as well. You can see the shiny spots where I tried to face it.



Once again it was time to dip into my brass stocks and fabricate a replacement. The part was squared up, drilled and tapped.



Here is a current family shot.



Till next time.

Tony


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Offline Kim

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Re: AOGís version of the Stuart S50 Engine
« Reply #26 on: December 10, 2018, 05:47:17 PM »
That's a bummer about the quality of the Stuart castings  :(
But nice progress on many parts regardless! :ThumbsUp:
Kim

Offline b.lindsey

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Re: AOGís version of the Stuart S50 Engine
« Reply #27 on: December 10, 2018, 10:40:28 PM »
Nice family shot too Tony.  :ThumbsUp:

Bill

Offline bent

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Re: AOGís version of the Stuart S50 Engine
« Reply #28 on: December 12, 2018, 04:49:48 PM »
Ugh...what a pain to try and cut hardened cast iron!  Glad you are perservering, AOG!

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #29 on: December 15, 2018, 09:00:56 PM »
I made more good progress this week. Continuing on with the valve work I made the valve rod next. First I turned down the end of the rod to fit the hole drilled into the far side of the valve chest.



Next I threaded both ends of the rod.



With the rod complete a squared up a piece of brass for the rod end and drilled it for the pin.



Then it was over to the lathe where I rounded the end and then drilled and tapped the part.



Next I stuck the round end into a collet block and cut the slot with a slitting saw. It turns out that the part rotated a little bit when I tightened the block so I wasnít perfectly aligned. It was nothing a little file work couldnít fix.



The next part was the connecting rod. I squared up a blank and mounted it in the four jaw chuck. Then I drilled it for a center. The belly of the rod was turned to the major dimension. Then I turned the near end to the minor dimension.



After a little trig I realized that the angle between the major and minor dimensions was less than half a degree. As I have no means of accurately setting the cross slide to that small of a dimension and since itís not a critical dimension , I decided to taper the rod the old fashioned way. Using my lathe files, I filed the taper until I found it acceptable.



Then the connecting rod was taken to the mill and the holes put in.



With the holes in I milled down the end to the minor dimension.



At this point I would have made some filing buttons to round over the ends but my drill rod order hasnít arrived yet so Iím calling this part complete for now. The last thing to get worked this week is the crosshead. The blank was squared up and put in the four jaw. I drilled and tapped the end.



Next I turned the boss on the end.



In the mill, the hole for the pin was drilled.



Then the slot was milled out. I tend to have problems with drifting on this type of operation but this one came out perfectly.



Lastly I milled the top to shape.



I mounted the crosshead in the guide to check for fit and it seams ok. Iíll leave you with this current family shot.



Till next time.

Tony


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Offline Ye-Ole Steam Dude

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Re: AOGís version of the Stuart S50 Engine
« Reply #30 on: December 15, 2018, 10:05:14 PM »
Hello Tony,

Very good progress pictures on this build.

Have a great day,
Thomas

Offline bent

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Re: AOGís version of the Stuart S50 Engine
« Reply #31 on: December 17, 2018, 08:12:47 PM »
Looking good, Tony!

Offline AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #32 on: Today at 04:13:26 AM »
Thanks everyone, I think itís time to close this one out. The next part made was the flywheel. Yet again I had a cast iron part that belongs on an artillery shell instead of an engine. This time I was at least able to get a usable part out of it. I started by trying to file off the flashing to get the casting semi presentable. The flashing was so hard I had to use a rasp to do the filing. My regular machine files were skating right over it. The good news is that other then some flashing on the spokes, the rest of the casting was in very good shape. The next thing I did was to clean up one side of the hub using a bump center to get it running as true as possible.



Then the part was flipped and the other center cleaned up and drilled.



Next I loctited the flywheel onto a mandrill for turning between centers. After the Loctite cured, I tried to face the front of the rim with no luck. I ended up breaking an insert trying. The same thing happened with the other face. Thankfully they werenít to bad so I just touched them up with my rasp. With those done I was able to break through the hardened outer layer on the outer circumference and get that to dimension. When you look at the picture you can see how thick the shiny (hard) areas are on the faces.



With that done, I heated up the mandrill and removed it from the flywheel. The last thing to do on the flywheel was to drill and tap the hub for a setscrew.



Needless to say Iíll be painting this flywheel. With that done I made the valve and piston nuts. They were both made the same way so Iíll only show one. First the outer diameter was turned for threading.



Then the thread was cut and the center drilled.



The nuts were parted off and cleaned up. The last part to make was the crank pin. The instructions call for you to make a slotted steel screw but since Iím not a fan of slotted screws and I have already fabricated a bunch of other things in this engine I decided to change it up. I had a scrap of the 5 BA hex stock that the piston nut was made from. I turned it to shape, threaded the end and parted it off.



With that done I grabbed a scrap of Corian and made a base. With the exception of the connecting rod (which still needs rounding over) that completes the metal work on this project. Itís time to pull it all apart and paint it. Here is a final family shot.



Till next time

Tony


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