I then proceeded to put the gasket rings on the piston and assemble the cross head and slide bars which will keep the piston motion straight in the cylinder bore. Here is where some common sense is needed when deciphering the directions. To be sure, the directions are fine, however sometimes things do not translate well, but thanks to the exploded drawings, things can be figured out with some careful thought. The directions call for the builder to not tighten down the screws which hold the slide bars to the rear cylinder cover. Later I learned that the only way to access the top screw was to tighten it before installing the steam chest. I think the idea was to keep the slide bars somewhat loose to allow for correction when making sure the piston slides smoothly without any hindrances.
Next was installing the steam branch pipes to both the cylinder block and steam chest or valve chest.
Then it was time to put those cylinder studs in the cylinder block. I had previously measured them and they needed to be 12mm in height when screwed into the cylinder block to allow for enough threads to hold the nut which sandwiches everything together after the valve timing is set at a later part of the build. I did add a bit of loctite 222 to the bottom of those threads to keep them from turning when I put on the nuts later.
Now it was time to set the valve and valve block into the steam chest. I added a bit of steam oil to coat the bottom. This will come in handy later when I do an air test. I had to install some set screws into the valve block which will bind down on the valve spindle. The block grips the valve spindle which is what moves the valve back and fourth over the ports, which in turn allow steam into the cylinder to move the piston.
The valve block has two holes for those set screws. It also has a hole running the length of the block which allows the valve spindle to slide in. The hole is at the bottom of the valve block and the holes for the set screw have a countersunk depression so it is clear which side is up. The diagram clearly shows the correct position of the valve and valve block, but it is hard to mess that up as the hole for the valve spindle which runs through the valve chest clearly shows which direction the valve and block need to face. I did have to lift the block up a bit to allow the spindle to enter it and this made the block rise up and slant down sort of like a ramp. I had talked with David Leech and he said this was normal. As the valve spindle is attached to the combination lever everything will line up as it should.
Here is where the I found the directions in section 2 to be a bit out of sequence. It calls for the assembly of the cylinder back plate and valve spindle guide to be added and then the valve spindle cross-head to be installed. Here is the problem with that order. The cylinder back plate has to go on the steam chest as it is being slid down the cylinder studs for it to clear the slide bar set screw which is holding it to the rear cylinder cover. The valve spindle cross head can not be attached to the valve spindle with the valve spindle guide already attached to the valve chest. So, I had to follow the diagram more than the written instructions, but in the end everything is as it should be. The piston moves smoothly as does the valve via the valve spindle.
Now, I need to assemble the other cylinder and then it will be on to section 3 which is putting the cylinders onto the chassis.
UPDATE I have completed the second cylinder. I'll try and get some pictures up later tonight. For those interested I was given an excellent website which has tons of info on steam locomotives, but in particular with the USRA Light Mikado. You can read about it here as well as get some photos of them.
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