Chris's Build of Steering Engine

[Michael S.]

Chris, nice that you own the book too.
I've had the book on my bedside table for a week now. I'll start reading tomorrow.
You are right the machine has the Stevenson controls. It is a two-cylinder low-pressure steam engine with injection condensation. Then there's the Penn backdrop. It should be complicated to use. Each cylinder can be controlled individually with a lever system, which is practiced when starting and then the levers are hung in the automatic.
There are different designs of the oscillating machines on the ships.
I'll do some research.

Michael

[crueby]

Chris, nice that you own the book too.
I've had the book on my bedside table for a week now. I'll start reading tomorrow.
You are right the machine has the Stevenson controls. It is a two-cylinder low-pressure steam engine with injection condensation. Then there's the Penn backdrop. It should be complicated to use. Each cylinder can be controlled individually with a lever system, which is practiced when starting and then the levers are hung in the automatic.
There are different designs of the oscillating machines on the ships.
I'll do some research.

Michael

Sounds good!   I scanned in the text pages (which are a bit beyond my limited German skills), and ran them through an Optical Character Recognition and translation to English, which will help my understanding of the details a lot. The operation details on the levers is still a bit confusing - probably one of those things that you need to see diagrammed out to completely understand.

[crueby]

I was out all this morning doing other things, but did get a little time in the shop this afternoon taking care of some more fiddly bits. The steering wheel hubs need locking screws, which in the pictures from Michael I see some with wing-nut style ends. Easy enough to make something that shape from some 5-40 socket head screws - clamped them sideways in the mill vise, and flattened off the sides:

making these winged ends:

I may go back and file the centers a little for more shape.
The other small piece needed on the hubs was a small retaining bracket for the large wheel hub, to keep it against the wall when the locking nut is loose and the clutch is not engaged (which is always when running the steering using the engine). Milled that from a bit of small square bar stock and screwed it to the flange on the rear wall:

The lip on the end of the bracket rides in the groove on the hub, holding it from sliding out. Now, I guess I got the first hint that Christmas is coming - I needed a very short 2-56 screw to hold that bracket, and was about to cut the end off a 1/4" long one (shortest I stock), when I found an already trimmed one laying on the floor next to the trash can. Perfect length, just needed to file a bur off the cut end. All I can figure is that the shop gnomes are trying to bribe me into getting them a new box of shiney parts for Christmas to add to their hoard. Either that, or their pet goat got scared off when I came into the shop and left the other half of his lunch laying there...   

Anyway, next will be to start in on turning the handles for the wheels. I need 12 of them all the same shape, so the plan is to set up the compound rest on the lathe and production-line turn each angle on a pile of handle blanks, adjust for the next angle, and go through them all again. Repeat till done with the dozen parts. Good thing to start on tomorrow...
 

[cnr6400]

 

[Michael S.]

That's a great idea with the wing screw! I'm really curious how the handles are made.
Grinding a steel for the lathe in the profile of the handles would also be an option. I used to do this for profiling the ends of masts for railings. But it was just a kind of ball.

Michael

 

[crueby]

That's a great idea with the wing screw! I'm really curious how the handles are made.
Grinding a steel for the lathe in the profile of the handles would also be an option. I used to do this for profiling the ends of masts for railings. But it was just a kind of ball.

Michael

 

That would work to get the outline, drill a shallow hole in the end, then mill the flats on either side.

[crueby]

Began shaping the spokes for the two wheels today. First cut 6 long and 6 short pieces of 303 rod, and squared up one end in the lathe on each. Then, using the tailstock with a center drill as a stop reference, measured back on the first one the height of the handle end of the spokes, and used a parting tool to cut in the diameter to fit the holes in the wood rims.

Once that first one was done, I swapped out the other 11 one at a time and made the same cut, same position and depth. That went quickly since the tailstock lined up each piece in the same place in the chuck.
Then turned each piece around, and turned the shafts down to size. Where they go through the rim is a larger diameter than the rest of the length. Since they are thin, each was done in short segments down the length of the rods. Kinda hard to see the steps to the diameter in this photo, but they are there - scaling down for the size of the photos for the forum loses some of the details.


This shot shows it better

Here are the parts so far test fit on the hubs. The ends of the spokes are a close fit into the holes in the hubs so they stay together nicely. At final assembly a little loctite should glue them in well.

Next time I'll start shaping the handle ends of the spokes...

[ddmckee54]

It's not so much the scaling that makes it hard to see...  It's that pile of strategically placed swarf behind the part that makes it hard to see the transitions.  No doubt it was put there by the shop gnomes in retaliation for chasing their goat away from the rest of his lunch.

[Michael S.]

I see what it's supposed to be. The workshop elves will soon have a nice new toy. They will argue who is allowed to steer!

Michael

[Michael S.]

Hello Chris,
I looked again for information on the oscillating steam engine in my books. There are few details about it. Even in the German steam engine Bible >> The development and history of the steam engine << from 1908 there is only one picture.
I think the control is complicated and therefore only simplified in the model construction book. A member of the German steam model forum built the machine with two eccentrics for forward and reverse driving and also changed the cylinders a bit.

Michael

[crueby]

Hello Chris,
I looked again for information on the oscillating steam engine in my books. There are few details about it. Even in the German steam engine Bible >> The development and history of the steam engine << from 1908 there is only one picture.
I think the control is complicated and therefore only simplified in the model construction book. A member of the German steam model forum built the machine with two eccentrics for forward and reverse driving and also changed the cylinders a bit.

Michael

The videos you posted of it running show a lot of the little details that they simplified in the book in the shape of the cylinders and other part, you'd definitely be able to add a lot of that back, especially if you scaled up the plans to make it half again or even double the size in the book.

[crueby]

I see what it's supposed to be. The workshop elves will soon have a nice new toy. They will argue who is allowed to steer!

Michael

While they are arguing over it, I'll get my turn!   

[crueby]

It's not so much the scaling that makes it hard to see...  It's that pile of strategically placed swarf behind the part that makes it hard to see the transitions.  No doubt it was put there by the shop gnomes in retaliation for chasing their goat away from the rest of his lunch.

At least brass goat exhaust is better smelling than the normal goats... 

[cnr6400]

I'm told that brass goats are far less likely to try and butt you while you're faced the other way. I'd still keep one eye open around goats (brass or the usual kind) 

[crueby]

Set up the compound slide, and shaped the handles on the spokes this morning. I used a variation on the old trick for shaping bearing caps, several flat cuts 10 or 15 degrees apart to simulate a true curve, then used a file to blend them together. Since the handles all have a step cut into them where the shank starts, that step was perfect for aligning the parts in the chuck - put the step against the jaws each time, and the parts are in a repeatable position so I could make the same cut on all 12 then change the angle.

Started out with a steep cut at the end.

changed the angle a bit for second one to start to turn the corner

a third to finish the corner


and one more to get close to the parallel cut down the length

The last cut was angled back in to narrow the base of the handle. Finished this cut at the base while leaving a bit of room for the reverse curve

That was it for the cuts, then just a final few swipes with a file to smooth the curves fair

All those steps were done on all 12 parts before moving on to the next cut, so at this point they are all done and ready for a test fit. Oh, and the rims were varnished yesterday, really brought up the color nicely.


a closer view of the small wheel. I am going to chuck them up one more time and trim a little of the hub ends to get them seated a little deeper to get the handles in the proper location, then a drop of loctite in the holes for final assembly.

Good time to break for lunch, and go outside and clear a few more leaves in the yard...