Steam Cylinder Heads, Pistons, Rods, Steam Manifold
Took time off from the engine to get the new bandsaw uncrated, disassembled, cleaned, hand carried in pieces down to the shop, reassembled and tuned-up with a Starrett blade. Cuts dead straight and very nice finish. Haven't named it yet, but I'm working on it.
That's it for the machine ****. Back to the engine.
The next parts are the steam cylinder heads. The top heads are flat with a 1/32" locating spigot on the back side. The bottom heads are drilled and tapped for the connecting rod pack nut.
I started with a brass round, turned to the needed diameter. I'm very happy with the finish from the round bit in the tangential tool holder. Unless I'm turning into a corner (as in the second pic), this tool is the one I like to use.
Turning and parting went without issue and then drilling and tapping for the piston rod in the lower heads.
The heads then (still in the 5C collet) were locked into a square collet block and moved to the mill for the bolt hole circle dance. Appropriate numbers were entered into the DRO and it's then just, DRO to Hole 1; display to 0,0. Hole2; display to 0,0. Repeat for all 6 holes. Replace part in collet. Do it all again.
On to the pistons. Another piece of brass round, turned until it fits almost nicely.
Then the Sorcerer's Powder. I got the sample kit: 1 tin each of 4, non-ferrous grits. Looks to be a lifetime supply. Mix a bit of the powder in some oil.
The oil-powder mix is spread onto the piston. Lathe at slow speed and gently lap the cylinder until the powder stops cutting. The difference between this stuff and Clover is that Timesaver breaks down as it works until it will no longer cut.
The instructions say to clean the parts with "Stoddard's Solvent." It took a bit a Googling until I found that Mineral Spirits are the same thing.
I'm know that this isn't the recommended way to lap a cylinder and piston, but the piston now moves through the cylinder with no binding and, a thumb on the end will hold it in position until released.
Oil grooves cut into the piston. It was then drilled and tapped for the piston rod and parted off.
Some .125 brass rod in a collet, threaded and done.
Hex rod in a 5C collet to make the two packing nuts. Just turned to diameter and threaded.
The finished nut threaded into the lowed head then both are drilled and reamed. I'm probably the last person on the forums to realize that reaming these "in place" will result in no binding. I saw a picture of this last week on Jo's demonstration engine. Head slap ensued followed by "Duh."
I now owe Jo TWO dinners.
More pieces completed. Of course, filing, sanding and polishing are in my future.
Next in line is the Steam Intake Manifold. A bit of brass from the bin and 3/16 brass tubing.
Totally unexciting squaring, cutting, drilling resulted in these.
One of the manifold blocks has a through hole for the steam/air tubing. The other is a stopped hole.
That block is silver soldered to the tubing.
After soldering, I soaked the assembly in citric acid (sour salts) for 10 minutes or so. Now to get rid of the "pink" color. Don't know if this is correct but I've read that the pink color is copper migrating to the surface of the brass.
The secret formula to remove the pink color and get the brass color back is: 3 parts white vinegar and 2 parts hydrogen peroxide. About a 15 minute soak seems to do it. Be careful of leaving it in too long as it will eventually begin to attack the metal.
I just did a quick assembly to be sure the manifold fits. Filing, sanding. Filing sanding. All is well.