Author Topic: Chris's Mann Wagon Build  (Read 130059 times)

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #60 on: June 02, 2020, 10:10:54 PM »
Last of the bushings are in, parts are cleaning up in the pickle solution. I realized that it would be better to drill the holes through into the engine mount ribs before soldering on the end caps, easier to locate the ribs for drilling. So, will likely do that tomorrow, then can start the final soldering. Pictures later when the parts are out of the cleaning.

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #61 on: June 02, 2020, 11:59:17 PM »
Soldered boiler subassemblies are cleaned up and ready to show. Here are the parts:

View from inside showing the engine mount ribs and bushings. Bushings are all stepped, larger on the inside, so the pressure can't blow them through the holes if the solder failed.

Outside view of the side bushings. The one on the right is at the centerline, takes a bolt from the end of the rear frame. The two lower down and to the left take bolts for the cab subframe supports. The one just visible at the bottom left is the boiler drain/blowdown bushing.


And here is why I decided to drill the engine mount holes before putting on the endcaps - this way I can use a ruler to mark the positions of the inside ribs, and transfer those lines back to the center. Also can measure in for the positions of the cross ribs.


The rib outlines marked out, and the hole positions sketched on:

Here is the engine base plate that will bolt on, the engine base will be silver soldered to this plate. A hole needs to be bored in the center for the steam dome opening - the inside of the engine base and the engine itself act as the steam dome on these machines.

Need to figure out how to drill matching holes in this plate - probably will drill one by clamping it to the boiler tube when the first hole is drilled in it, then use that as a locating pin to drill the rest. Will take a lot of bolting/unbolting, but they all need to align with each other. Since the studs go in perpendicular to the shell, the holes in this plate will need to be elongated towards the middle so they can slip over the bolts all round. There will be a gasket around the steam opening in the center to seal it all up.

Offline Trevorc

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Re: Chris's Mann Wagon Build
« Reply #62 on: June 03, 2020, 10:04:58 AM »
That sounds a little unusual to elongate the holes in the plate so they slip over the studs. I would think this would increase the challenge of getting a good seal between boiler shell and engine cylinder plate.
On my 4 inch scale Foster traction engine the holes in the cylinder plate were circular and the studs were fitted after the plated was in position.
My other concern would be that the screw thread in the boiler is only as long as the  shell thickness so it is easily damaged.
Are you sure that the plate is silver soldered to the underside of the engine cylinder? My instincts say that it should be soldered to the boiler shell to give added local stiffness to the boiler shell and also give increased length of screw thread holding the studs.
Regards
Trevorc

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #63 on: June 03, 2020, 01:47:25 PM »
Hi Trevor,


I put the thick ribs on the inside of the boiler shell so that I can run the threads in 1/4" and still be in solid metal. Being bronze, the ribs will hold better than just copper would too. I am debating using fixed studs, which would require elongating the holes in the outer plate. May instead make the studs with the nuts fixed on, so they would act like bolts and come out with the nuts. I want to have the engine removable if needed, but unscrewing a 5-40 stud without damaging the thread on it can be tricky. Making the stud and nut as one piece would look right but function easier. I think. This is at a smaller scale than your engine so the threads are smaller. Thoughts on that approach?


Chris

Offline Don1966

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Re: Chris's Mann Wagon Build
« Reply #64 on: June 03, 2020, 05:13:36 PM »
 :Love:


 :cheers:
Don

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #65 on: June 03, 2020, 05:24:20 PM »
Here again is the set of ribs on the inside that the engine plate bolts will go into - these ribs are bronze, so plenty strong to hold the threads. There are gaps along the shell on all four ribs to let the steam/water flow by and not be trapped in a bubble.

I started out by clamping the boiler tube on the mill, and lined up the bolt holes on one side, counting out the number of turns from hole to hole. Put the table at one end of the row, and clamped the engine base plate in place, then drilled the holes in that row, and counter-bored the holes in the plate to the clearance size:

Took the parts out, tapped the holes, and lined up on the second side. Screwed the plate on with the end holes in the first row, plus the c clamps near the second row, and drilled that row:



These holes go in 1/4", stopping short of the bottom of the ribs. Then lined up for the holes along the ends:



With lots of double-checking, none of the holes broke through the sides of the ribs (big relief). All are now tapped to hold the plate. I think I am going to go with the bolts-that-look-like-a-stud approach - elongating the holes would require too long a slot, and removing the studs to get the plate off would be a pain. So, will make the studs and loctite the nuts to them (silver solder would work too, but I think loctite will be enough - can always redo them if a nut loosens up, and it wont mess with the hardness).
Next I can drill/bore the hole in the plate for the steam dome opening. 

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #66 on: June 04, 2020, 10:24:00 PM »
Both endcaps soldered on today, boiler is bathing in the pickle bucket now. Initial gross leak test passed when rinsing off the torch scale, plugged openings with fingers and filled it up. No noticeable drips, so thats a good sign. Won't know for sure how it went till I can get the blanking plugs and pressure test rig set up for the hydraulic testing. Pictures later after the pickle bath...

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #67 on: June 04, 2020, 11:43:23 PM »
As promised, pictures of the boiler with the endcaps silver soldered on. Visually the joints look good, no starved spots, and it holds water with no pressure so no obvious gaps. Here is the backhead:


front end...

and with the engine plate and smokebox slipped on - the smokebox will be riveted onto the boiler shell where it extents beyond the endcap only after the pressure testing is complete, in case there is any re-soldering needed.

Next step will be to make up the pressure test rig - adapter to the hose from the hand pump to pressurize it with water, and also for the pressure gauge. Those will be easy to fit to the threaded bushings, also need a blanking plate for the steam dome opening. I may go ahead and make the bottom bit of the engine base, which will be radiused out underneath to match and soldered to the engine plate, with a flat top to bolt to the engine. That could make an easy way to plug that opening, as well as test the gasketing for the engine plate. I have the adapters from the Marion boiler build, have to dig them out of the drawer and see what threads they are and whether I need to make new threaded ends.

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #68 on: June 05, 2020, 08:59:06 PM »
Not much shop time today, been outside most of it enjoying the warm weather. Once done with the rockers on the porch for the afternoon, took the opportunity to put a fresh coat of oil finish on them.
I did get the setup for milling the engine base figured out. Found a chunk of stainless that was the large enough for the lower base, and decided how I am going to shape the curve in the lower face - will screw it to the larger block behind it, which can be clamped to the tooling plate on the rotary table and allow for adjusting the distance from center. The screw holes will be the same as used to bolt the engine down later, the screws countersunk in from underneath so they wont show. Matching screw holes will need to be drilled in the copper base plate, and this base will be silver soldered to the copper plate. This will allow the engine to be removed from the boiler, also allow the upper engine block to be separated from the base block. Sounds complicated, but once all done it is straightforward.

The centerline marked on the block is off center, towards the lower left in the photo. This is intentional, since the engine block is larger on one side for the low pressure cylinder, the base is wider on that side and goes a little farther around the curve of the boiler. The sides of the block will get angled to match the shapes on the engine.

Offline cnr6400

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Re: Chris's Mann Wagon Build
« Reply #69 on: June 05, 2020, 11:59:17 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn

Boiler work looks great! Hi Yoh Silver (solder)!
"I've cut that stock three times, and it's still too short!"

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #70 on: June 06, 2020, 05:05:32 AM »
:ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn

Boiler work looks great! Hi Yoh Silver (solder)!


I checked the bucket under the separator on the shop vac, and I think that Silver took a, um, swarf, in there. 5 gallon bucket is nearly full!!   :lolb:

Offline cnr6400

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Re: Chris's Mann Wagon Build
« Reply #71 on: June 06, 2020, 01:45:31 PM »
They say that if a bird takes a >delivered swarf< on your head it is good luck. With what you mentioned in your bucket you should have good luck for life!  :Lol:
"I've cut that stock three times, and it's still too short!"

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #72 on: June 06, 2020, 10:55:46 PM »
They say that if a bird takes a >delivered swarf< on your head it is good luck. With what you mentioned in your bucket you should have good luck for life!  :Lol:
Somehow I don't think bird exhaust is good luck in any way!   :ShakeHead:
No shop time today, but I did take that bucket o swarf out. Had to weigh it, 40 pounds! Guess I have to empty it more often...

Offline crueby

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Re: Chris's Mann Wagon Build
« Reply #73 on: June 07, 2020, 05:20:05 PM »
Back in the shop again today, and got the holes drilled/tapped for the engine base and the bar to hold it to the tooling plate:

About halfway into milling the arc in the base...

Offline Don1966

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Re: Chris's Mann Wagon Build
« Reply #74 on: June 07, 2020, 05:43:54 PM »
Lovely work Dog.......... :Love:




 :drinking-41:
Don

 

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