Author Topic: AOGís version of the Stuart S50 Engine  (Read 1344 times)

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  :)

Online 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...:)

Online 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

Online 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.  :)

Online 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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Online 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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Online 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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Online 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