Chris's Slew-Crowd Engines

[crueby]

Looks like you had a fun and productive time!  800 shots!  That's pretty good 

Kim

The elves tried doing 800 shots, but fell off the workbench partway through. Helps that their 'shot' is barely one drop for us!   

[cnr6400]

  The model valve work looks great Chris! 

The Dreadnaught Erie crane pics were great to see. Glad you had a good day visiting the site. Nice looking Frick traction engine too. The shovel without the cab is interesting.

[Roger B]

That's an interesting throttle and reversing system. It would be quite easy to make with cored castings, not so easy machine from solid     

An interesting visit to the steam shovel. I am always amazed how different American traction engines look compared to European ones.

[crueby]

That's an interesting throttle and reversing system. It would be quite easy to make with cored castings, not so easy machine from solid 

An interesting visit to the steam shovel. I am always amazed how different American traction engines look compared to European ones.

The molds/cores castings would have been very interesting to see on this type of engine, for sure.

The American traction engines came in quite a variety of styles and sizes. How do they differ from the European ones, in general? The farms here tended to be larger on flatter ground, and I don't think the cable-drum ploughing engines were used here much. They did get used for driving other stationary machines quite a lot.

[crueby]

This morning started making up the valves for the Marion engine - they are a little larger than the others, and I will start with them. The ones for the other engines are quite close to each other in size, and I may be able to combine them into one batch. But, to start, I need to make up the raw blocks from bearing bronze. As on the last several engines, I am cutting the bronze down from a leftover piece of large cored bronze that was used to make cylinders back on a larger engine a few years ago. That cored piece was bought as a drop from one of the pliers.  Here is what is left. I've been taking slices off of it, then cutting them into smaller blocks. You can see part of a slice just to the left of the cored block. Goes a lot faster than cutting down from round bar.

And the first valve block milled down to size to start detail shaping. I'll have to keep it locked up so the elves don't steel the 'gold bar'!   

While working on that, I had the 3D printer knocking me out a little spanner wrench to use as a barring lever on the engines during valve timing work. It will let me do small movements on the crankshafts a lot easier.

Started with the shape of the gear in CAD, and drew the lever around it. After printing I had to file back the end of the inner curve opposite the three teeth to let it slip into place easier. a hinged one with one tooth would be more common if made in metal, but the one piece plastic one was very quick to draw up and print.

So, will continue on roughing out the valve blocks, then get started cutting in the recesses...

[cnr6400]

  A great start to the valves! Good plan re locking up that solid gold bar... I like the printed wrench! Three teeth eh? that reminded me of a couple of my cousins "way up North"... they're like extras for the locals in Deliverance, but a lot colder...

[bent]

Wow, that open truss boom on the clamshell rig is familiar - same used on the '60s era dredges on the Mekong.  Very cool photos, and cool that you can help them out (in exchange for some operator time, I'm sure?).

[Roger B]

The American traction engines came in quite a variety of styles and sizes. How do they differ from the European ones, in general? The farms here tended to be larger on flatter ground, and I don't think the cable-drum ploughing engines were used here much. They did get used for driving other stationary machines quite a lot.

The biggest differences I see between the American and European traction engines are the round spoked front wheels and the amount of boiler/smoke box in front of the front axel. Here are couple of engines from the web.

[cnr6400]

Hi Roger, one other major difference between UK and North American steam traction engine practice is the use of horn plates each side of the firebox in the UK but not in N.A. On North American engines the rear axles are either side mount (axle brackets bolted directly to the firebox side sheets) or rear mount (axle and bearings mounted to a sub frame the boiler is mounted to, with the axle behind the boiler). The engines themselves are usually bolted to the boiler top sheets and barrel. Some makes had a large sub frame on top of the boiler for the engine and crankshaft mountings combined, which was claimed to "keep it from getting out of line" but other makes mounted the cylinder to the boiler on separate brackets from the brackets that mounted the crankshafts, with adjustments designed in that allowed alignment of the running components.

For engines intended for heavy plowing, rear mount design reduced the strain on the boiler by not having traction / load forces transmitted or borne by the boiler. Side mount engines working in the belt (driving other implements) or moving themselves from farm to farm rarely had issues with axle forces distorting the extra heavy firebox sheets. (there were some exceptions and resulting boiler accidents of course).

The biggest of the US built engines was the truly huge Case 150 HP traction engine. No complete original one exists, but Kory Anderson has built a full size new build of one. You can see it pulling 44 plows breaking sod , or in a tug of war with a huge modern diesel Cat D11 bulldozer on You tube. Just search for "Kory Anderson Case 150"

[Sanjay F]

I had to look, it's immense, what a piece of engineering, take a look at the images   

https://150case.com/

[crueby]

Thanks for the info on the UK/US traction engine differences, guys!  Very interesting stuff. And I had forgotten about that Case 150, had seen the video of it pulling the line of plows, what a beast! Always amazed at the power of steam with even a single cylinder.

[crueby]

Busy morning in the shop!  Got the blanks for the Marion cylinder valves taken to overall shape yesterday, this morning I marked out the chambers in the underside to help keep things straight when milling - the milling will be done with measuring, the lines are just for reference so I don't get mixed up on which end is which!

Then drilled through from one end with a 4-40 tap size drill, deep enough to reach the chamber on the other end but not break through the far end wall. The two end chambers will be deep enough to reach these holes to connect them, the center chamber is shallow and does not connect to the holes. On the original engines, there would have been a curved wide passage rather than the two holes.

and tapped the ends of the holes 4-40...

Then some very careful milling with a 1/16" end mill to form the chambers. The two end chambers were taken down in several passes to meet the holes. Lots of stopping to measure distances across the chambers and the separating walls. The walls are wide enough to cover the ports in the valve plate with a little lap overhang.

Here I have loctited in the ends of screws. After letting them set up a bit, I sawed off the screws flush with the end wall. So, the two holes connect the two end chambers and are now plugged at the end wall.

After trimming the screws off, the bottom faces were lapped on a diamond plate to get them dead flat and smooth. Then they were assembled in with jam nuts either end of the valve rod, so they can still float on the rod. You can see the ends of the lines that I had drawn next to the ports. Its hard to see but there are also lines on the side of the valves to show where the walls are. I used these lines to do an initial centering of the travel of the valves.

Then got the cover plate back on, and it was ready to time the valves!

With the compressor hooked up, I started some tests for the timing, and adjusting the eccentrics on the crankshaft. First thing I found was that one eccentric was 180 out, so the two cylinders were trying to run in opposite directions!      With that spun round, did more timing work, adjusting the angles of the eccentrics and also tweaking the length of the valve rods by turning the fittings at the outer ends of the rods where they meet the levers. So far I can make it run in either direction about 3/4 of a turn, so the timing is CLOSE. good place to break for lunch, and this afternoon I'll probably get back at it to try and zero in on the settings. For the initial timing I had the end cover off of the cylinders so I could listen/feel for the air coming out the port at that end of the cylinders, that got it close. It will either be running this afternoon, or take days - hard to tell! I'm hoping the distances on the chambers are right, otherwise I'll need to remake them. Stay tuned!
 

[bent]

 So close! 

[cnr6400]

  "Copy, Eagle. Houston standing by." 

[crueby]

After lunch, fresh look at the timing...  little more angle here, little less there, lengthen the rod on that cylinder, and ... it smoothed right out!!  Well, in one direction anyway. Was just reaching for the camera when it started to stutter and make an intermittant loud hiss sound. What the... turns out that the screw holding one side of one of the piston glands in place vibrated loose and it started blowing air out past the piston rod.   

So, two steps forward, then one into a pile of ... something.

But, at least I know the valves are good dimensions are are sealing well!      No blowby past the piston seals...     Just need to fix that screw. Problem is, getting to it! To get to it from the crank end, I'd need to take out the crosshead, which means taking out the valve lever top plate and all its connections, then can get to the wrist pin and undo the crosshead, also taking out the connecting rod...      Yup, nice compact engine!     No room to get at things in the middle at this scale.

The other way is to disconnect the cylinders from the frame, and pull the cylinders outwards and off the pistons. That would just mean undoing the pivot bolts on the ends of the valve rods, which is simple. If I do it that way, I can also fix the one slight leak on the gasket around the frame end cylinder cap.

This time, a dab of blue loctite on those screws to keep them from vibrating loose! 

I'm still counting this as a win though, it was running nice and smooth for about 20 seconds, which valipdates SO many parts and dimensions.      Just wish I'd gotten the camera on before it went off exploring at the canal turn...