Chris's Mann Wagon Build

[pgp001]

This is what the full size version looks like on a Mann tractor.



I think Chris is doing more of a freelance version than an absolute scale model, so his will not have the sliding eccentric for reversing, and a different mechanism for gear selecting.
The model also has the eccentrics outside the cranks, I presume it will be having a fairly conventional set of outside slide valve gear.

However he does it I am still flabbergasted at the speed it is coming together.

Phil

[crueby]

TGHS/Phil,

This model will not have the center support for the crankshaft. The sliding eccentric, which was Mann's patented mechanism and the reason for 'Patent' in the Mann Patent Steam Wagon naming, was actually only used on the smaller (3 ton and under) versions of the tractors/wagons. The 5-ton and above used a standard set of ecentrics and Stephensons linkage, so that is what I am using in this model of a 5-ton wagon.
If you look at the old photos, you can see the difference in the engines as well - some (with the patent reverse gear) have the valve chests on the inside of the cylinders, and some (with standard eccentrics) have the steam chests on the outside. And, of course, the Undertype wagons were yet another set of configurations! Fortunately I found an old Mann catalog that shows the different setups.That all said, it is true that I am not following the Mann transmission setup exactly, mainly since I don't know what it is for the 5-ton wagons so I am going from the old photos and line drawings that I have found, to get as close as I can. If the Vancouver museum was a continent closer and not across a closed border, I would have made the trip to take detail measurements/photos myself - I was able to get some photos from the curator out there, who very kindly supplied what he had. The setup I have matches the line drawings from the period that I have of the Mann setup, so it is pretty close to correct. The setup that Phil showed is for a smaller tractor with the patent gear and valves on the inside. Mine is based on the drawings and on the pictures of the Vancouver 5-ton wagon, with eccentrics and valves on the outside.Hope all that makes sense, I may have talked in circles there for a bit!   
Chris

[ddmckee54]

Chris:

When you spin the crankshaft, do you make the required chuff-chuff sounds, or do the elves?  You DO know the sound effects are mandatory don't you?

Don

[steam guy willy]

Hi Chris ,....just happend to see this on the web...........

There's more than one way to skin a cat !!!

<a href="https://www.youtube.com/watch?v=9sQzedI_Cw4" target="_blank">http://www.youtube.com/watch?v=9sQzedI_Cw4</a>

Willy

[crueby]

Chris:

When you spin the crankshaft, do you make the required chuff-chuff sounds, or do the elves?  You DO know the sound effects are mandatory don't you?

Don

Um, its the elves. Not me. Nope, you misheard...   

[crueby]

Hi Chris ,....just happend to see this on the web...........

There's more than one way to skin a cat !!!

[youtube1]https://youtu.be/9sQzedI_Cw4[/youtube1]

Willy

Willy, that's a slick approach. I like that guy's style, have to watch more of his videos. Thanks!

[crueby]

Today got a start on the flywheel, beginning with the taper lock for the hub. Got blanks made for the flywheel and for the lock, and drilled them to 1/4" for the crankshaft end. Then used the compound slide to put a 5 degree taper into the hole in the flywheel.

Matching taper on the outside of the lock piece - took this down till the lock would go almost all the way into the hub, leaving a little room to snug up on the crankshaft.

Over to the rotary table on the mill to drill the holes in both pieces. The flywheel got two 4-40 tapped holes, 180 degrees apart. The lock got two 4-40 clearance holes 180 degrees apart, and also one 4-40 tapped hole between them.  The first holes are used to draw the lock tight on the crankshaft, like a collet. The extra hole in the lock is used to break the hold, since by just loosening the two screws it is still difficult to get the tapered parts apart. Running a screw into this extra hole pushes the lock out of the hub without needing to pry on the surfaces.

Here are the pieces ready - the lock has been parted off from the bar, and the holes tapped. Also cut a slot through the side of the lock, opposite the tapped hole, so that it can be drawn down tight around the crankshaft.


Last step accomplished today was to start turning the recesses where the spokes will be. Chucked a 1/4" rod in the 3-jaw, and tightened the taper lock down on it. Plenty of grip, did not have any slippage and it is running true. Makes for a built-in arbor for doing the spokes.

I've got a drawing for the spoke hole layout from the 3D CAD model, next time will start cutting the spokes in.

[cnr6400]

 

Does a 5 degree taper give the other engine parts 5 degrees of separation from the flywheel ?    

Hope this philosophical question doesn't make the elves' and Mr Ethan Oll's heads hurt after all those Elfensteiner stubbies yesterday.......

[crueby]

Does a 5 degree taper give the other engine parts 5 degrees of separation from the flywheel ?    

Hope this philosophical question doesn't make the elves' and Mr Ethan Oll's heads hurt after all those Elfensteiner stubbies yesterday.......

Well, Kevin, the elves do like Bacon...   

[pgp001]

Chris

Thanks for the explanation of the differences between the tractor and the five ton wagon.
To be honest I have never delved that deeply into the differences in design and did not realise just how far apart they are.

I bet that sliding eccentric would be tricky to pull off in a small model as well, much more sense to use something that we know will work anyway.

Whatever you do it will be impressive I am sure.

Phil

[crueby]

Chris

Thanks for the explanation of the differences between the tractor and the five ton wagon.
To be honest I have never delved that deeply into the differences in design and did not realise just how far apart they are.

I bet that sliding eccentric would be tricky to pull off in a small model as well, much more sense to use something that we know will work anyway.

Whatever you do it will be impressive I am sure.

Phil

I'd like to make an engine with the sliding eccentric sometime, but as you say it would need to be larger. The Mann patent on it gives all the details, as do a couple of the books.

[crueby]

And finishing up the flywheel, I deepened up the recesses on either side, and moved it over to the mill to cut the spokes using the rotary table. The hole patterns were determined on the 3D CAD model, and a plan printed out with the distances and angles (shown in photo below). Started by plunge-cutting the 1/4" holes at the base of each spoke.

The arc at the base of each spoke does not have a common center, so another plunge cut was done 8 degrees farther over:

Then switched to a 1/8" end mill and drilled the holes at the outer ends of each spoke. It looks like a complex pattern, but its just a matter of locating the first hole on either side of the first spoke, and advancing 72 degrees at a time to the next hole.


Then moved the table in slightly, and chain-drilled between the holes along each arc. The reason for moving in was to ensure that I could do a clean-up pass on each arc and not have any wandered-holes leaving a mark.

A couple holes along each spoke edge, again in a little from the finished edge, and the rest of the material in the center of each hole fell out.

Then back to do a cleanup pass on each arc at the rim:

and a straight line pass on the first edge of each spoke

and last a pass on the other edge of each spoke

and the finished flywheel, sitting on the diagram I mentioned showing the angles and distances.

Then a session in the nickel plating solution, each part seperate, and its all done. I did need to give the center hole a twist with a 1/4" reamer to get rid of the slight thickness added by the plating on the edges of the hole, just enough to make it hard to push it onto the crankshaft.


Next, I think the con-rods...

[cnr6400]

Chris has spoken.

5 spoken, in fact. 

Looking great! 

[crueby]

Trial steaming before Christmas ?

Phil

Possible but not very likely. Lots of little things, conrods, eccentric followers, piping, throttle, reverse gear and controls, to go still. Not to mention a two cylinder compound engine!  Guessing more like late January or early February?

Definitely not going to be done by Christmas. Was looking at the remaining plan sheets and did a quick parts count. Not including the off the shelf fasteners, there are 175 pieces still to make! Some are quick, threaded studs, some are made of multiple pieces like the crosshead guides. Plenty o work left to go!!

[crueby]

Chris has spoken.

5 spoken, in fact. 

Looking great! 

I hath spaken? Pass the bacon!