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One step I didn't take a picture of was the milling of one long rough cut side to give me a straight edge so I can mill the second side parallel to the first.
Here I've set up a parallel to line up the part with for milling the second rough cut side parallel with the first side. I used an indicator to tram in the parallel
to be true with the "Y" axis.
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The part is clamped down and a light cut is taken. The size is measured and an adjustment is made to
give the finished size. Then the other piece can be clamped in and cut to size. The base for the frame was also milled in the same setup.
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Once the sides were milled to size the ends needed to be mill square to the sides. Here I'm squaring
up the parallels so I can cut the ends square. The table was first squared with an indicator along the edge of the table.
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A final check with an indicator to make sure the parallels are square.
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Next the ends are milled. The procedure is the same as the sides. A light cut is
taken on one end to clean up the rough saw cut and to square the end with one side. It is then reversed so the other rough end can be mill. A light
cut is taken and a measurement is taken so a final cut setting can be set and the part milled to proper length.
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Now that both the foot and the frame of the engine are milled to size, it's
time to mark out the holes that are called for in the print. Here are the tools that I'll be using to layout the holes and further cuts that need
to be made. I'm using an angle plate, a 1-2-3 block, 6" scale and a surface gage. The surface plate is a piece of marble I picked up many
years ago in Vermont. It's to soft for continuous use but will have to do for now. Any surface that's hard can be used. Such as a table saw,
plate glass or a piece of granite as long as it's flat.
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The first line is to be marked at a height of 0.500" inch. The scriber is set to that height
and a line is scribed.
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And here's what it should look like.
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Here they are all marked out ready to have the center's punched.
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These are the tools that are used to make punch marks on the part. The top is an automatic punch center
punch. It is spring loaded and all you have to do is push down on it until the prick punches the part. No hammer is needed with this tool. The next one down is a "prick"
punch. So called because it has a very sharp point to be able to pick up the intersection of the scribe lines to be marked. The bottom tool is a home made "center" punch.
So called because it has a 60 degrees point to make the prick punch mark larger. This makes it easier to center the center drill when drilling starts.
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I'm using the automatic prick punch to mark the hole.
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The base and frame all done ready to be drilled and milled to final specs.
The cross hatched marks mark the area that is going to get cut out. It helps to mark parts like this so you don't get confused as to which way to
mill the sides and what part is waste.
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While waiting to get some 2-56 flat head screws I made two flywheels. Nothing
mysterious here. Just some straight forward turning on the right flywheel. The left one I made a template in a cad program, printed it out and glued
it to the face of the flywheel. In order to drill the 1/4" holes around the part I mounted the flywheel on a sacrificial aluminum table strapped to the
mill table. I then drilled a hole and tapped it for a screw that would fit through the center hole. This established the center line of the flywheel.
Next I moved the mill axis .400". I then lined up the punch mark I had made in each of the holes. Using a sharp pointed piece of drill rod chucked in
the drill chuck, I lined up the punch mark, then drilled with a 1/4" drill. Repeat 7 times. Works great if you don't have an index table.
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Here are the frames with the first hole marked for attaching the base to it.
The reason I only laid out one hole is that I'm going to "match drill" the second hole in the frame. It's difficult to get the second hole at the
exact location since the holes may not have been accurate in the base to begin with.
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Here's how it's done. When I drilled and tapped the first holes in the frame
the center line was established on the "Y" axis. Using this first hole the base was then screwed to the frame leaving a slightly loose fit.
The "clearance drill" that was used to drill the hole in the base is then used for lining up the second hole. Lightly hold the part in the
vice, bring down the drill into the hole and it will then line up were the second hole is to be. Lightly drill with with this drill to leave a
dimple for the tap drill. Remove the base and drill with the proper drill.
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Next I milled out the waste that was laid out earlier. I clamped the same
piece of sacrificial aluminum I'd used for the flywheel to the table to use under the frame for this part of the operation. Using a 3/8"
end mill gave me the 3/16" radius in the corner. I lined the part up with the back of the table. Close enough for this operation.
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Here's what it looks like all milled out.
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The frame and base assembled and the two flywheels. Still a ways to
go yet.
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I worked on the cylinders next. I have two bronze blocks of 4" long
by 2 3/4" wide by 1 1/2" thick. I decided I was going to use this material for my cylinders. I cut out two blocks on my table saw with a carbide
blade. Worked quite well. Here I'm making the first cut.
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And here's the first rough cylinder block. One more to go.
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Second cut. Notice I've blocked the piece in using a piece of wood. I didn't
want my fingers any were near that blade.
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Here are the two rough cylinders and what's left of the one block of bronze.
Many more cylinders, pistons, etc to be made from what's left over.
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Next I milled one side flat in the mill.
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Then I set up the Sherline lathe to fly cut the sides flat and parallel to each
other.
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Next a fence was set up parallel to the lathe axis and a stop added so the
ends would be square to the sides and both parts would be the same length.
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The chuck was changed to a four jaw. The center of the bore was marked
out and trued in the four jaw. Next the hole was center drilled and then drilled with a drill large enough so a boring bar could be used next
to give a straight bore.
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Here the cylinder is being bored out with a small carbide boring bar. I had
to quickly make the boring bar holder for the lathe before I could proceed. Nothing like making tooling during a project. To check size of the bore
I made an aluminum plug to check for size of the bore. It should be .375" according to the print, but wound up around .382". That's ok since the
piston will be made to fit the bore. Remember, were not making production parts here. It's one of a kind so fitting parts together is OK.
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In order to get a flat bottom, something you won't get from just a drilled
hole, I used a .375" four lipped carbide end mill. I just happened to have that on hand and used it. A two lipped HSS end mill would have worked also
or any other tool that would cut a flat bottom. Once this was done I used a boring bar to put in the under cut at the bottom of the bore.
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So this brings the engine up to six parts done or about half way. The pistons are turned and
polished from a piece of 1/2" 316 stainless steel to fit the bore. The crank shaft is a piece of 3/16" tool steel and the crank shaft bushing
is a piece of bearing bronze. Holes for the air/steam still need to be drilled into the body. That's why the bushings haven't been pressed
in yet. Progress is slow but steady.
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Next is making a connecting rod. Here is a pic of the rough piece and the
finished rod ready to screw into the piston.
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The rough part being center drilled.
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This view gives a better idea of why the part was center drilled. It's for the
center in the tailstock to hold the part far enough out so it can be turned to proper size.
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As you can see the part is in a different lathe. I messed up the first part
that I was doing in the Sherline lathe. I used a longer rough piece and started to turn to the 1/8" dia. required for the rod. I turned a small
section to 1/8" and then moved further to the head stock and turned the next section. If turned all at once there is the possibility of pushing the
turned part away from the cutter due to springing in the part.
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Here the con rod has been threaded and is being parted off.
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The part that looks like dumb bells is the part that was done in the Sherline.
The dia was turned to small for the end that needed to be connected to the crank. The part below that is the one just parted off in the previous
pic. The bottom one is from the first engine and is what it should look like when done.
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The rod has been clamped in a V block and the V block clamped in the
vie ready to have one side milled flat.
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The rod has been milled on both sides to about 1/8" thickness and is
being reamed to fit over the 1/16" pin on the crank wheel.
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Here I'm test fitting the con rod for proper size. The fit is fine.
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Here's a pic of it finished and running.
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Here's a video of it running. Warning to those with dial up.
The vid is 2.1 Megs large and will take a while to load.
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