Oscillator Cylinder Pattern

[vtsteam]

All these oscillating steam engines everybody is building or renewing now...... makes me wish I was, too. My shop is basically unheated and temps outside this winter are no fun for me. I do have a little electric heater out there that struggles to alter things for the better, but the cold concrete floor just sucks heat out of my boots. Anyway, enough complaints!

Maybe instead of a complete engine I thought could just start on one thing -- maybe just a pattern for a cylinder. No chance of casting until outdoor temps are better and some of the snow is gone. But just the pattern might be fun for now, and make me feel like I'm doing something. And I can probably duck in and out of the shop, and do some of the work inside the house, since wood is my choice for pattern making.

I'd like something decent size, maybe inch and a half bore or so, I'm thinking. I don't have any 3" dry clear square stock to turn it from, and besides I was thinking last night, what if I tried assembling it out of pieces I cut out of scrap pine using my collection of odd size hole saws? String the pieces together like beads on a 1/4" dowel. Shish-kebab cylinder. Seems like a doable way. Could be fun.

So I picked through the saws I had and came up with a set of three, that seemed close enough. I started drilling. Or sawing, or whatever you call it. Trepanning? Anyway, making sawdust in the process, and not in the metal lathe for a change.

[vtsteam]

Just a test of stringing them together. I'll trim some of these down a bit, maybe the core prints and the flanges. But I think this will work.

[vtsteam]

To add a trunnion face, I took one of the plugs and sandwiched it together with three other pieces of wood, then drilled with the hole saw down into the end of the face to make a hollow:

[vtsteam]

And another mock-up of the rough cut pieces together:

[Sanjay F]

This is great, I'm glad you have found something you can do during the 'cold times' and I'm fascinated by the process so you have me hooked and following along

[CI]

Nice looking patterns !
The beauty of wood patterns is you can cut, sand, carve, add, subtract, etc. indefinitely, and easily.
Trying to modify 3D printed parts can be challenging.
And the reason I like to work with steel to build things is that like wood, you can cut, sand, bend, add, subtract, etc.

I bought a 240 volt heater, and when it is really cold, I will string a piece of Romex (tm) on the ground out to the shed.
Not safe I know, but it works in a pinch.

We have what is considered "cold" weather here today, at 19F.
Normally we don't get below 30F.
I checked the weather at a buddy of mine's place in Ohio, and he was at 9F today.

I have poured aluminum at 30F.
An oil burner operating on diesel works fine with no fuel preheat at 30F.
I put a cardboard box over the mold, and put a 1,500 W hair dryer into one corner, so the mold remained at about 70F.
I flipped the box off at the last second.
I recall there was a significant amount of ice on the ground, so you can't use ice and snow as an excuse to not pour.

I need to get back to doing some pattern work.
So many things get in the way of having fun.
.

[vtsteam]

Thanks Sanjay!

I recall there was a significant amount of ice on the ground, so you can't use ice and snow as an excuse to not pour.

@CI I've poured in winter here in Vermont before which is far north of you. I mold outside, my greensand is presently frozen, and as I said I'm going to wait a bit.

[CI]

Down here, heat exhaustion is a real problem for much of the year, especially when wearing full leathers, which is why I pour at night.
Frozen sand would be problematic.
.

[vtsteam]

I glued the pieces together this evening, but not the trunion piece. It will be easier to fillet the cheek pieces without that in the way.

The hole saw I used to cut the core print pieces was chosen to match the ID of a piece of 1-1/4" PVC water pipe. The reason was to simplify making a core box. The pipe will be split to do that so it can be opened to release the core.

A piece of pipe is shown here, just fitting the core print.

[CI]

You can slit the PVC down one side, and pry it open slightly to release the core.
Some peopple cut the PVC in half, and use clamps, but it is much easier to leave it one piece and just slit the side.
You may already be aware of this.
.

[PaulR]

  I know nothing about casting and pattern-making so this will be an education if I can keep up with it.

My garage workshop is also fairly cold at the minute although I have a double thickness strip of carpet in front of my bench to help with the concrete floor. I have so few sockets that I don't have any heating in the evenings thanks to those bloody Christmas lights 

[Jasonb]

Now if you want that larger engine to perform you will have to start looking into slotted ports rather than the simpler holes that tend to be used on smaller engines This generally allows more steam/air in and out sooner a bit like having a wider slot on a slide valve engine Also conside a couple ofg small blocks between the round port body an dthe end flanges so you don't have to drill the passages very close to the cylinder walls.

Also it starts to become a heavier weight hanging off the pivot pin so depending on whether you are making a vertical or horizontal engine you may want to add a boss on the opposite side of the cylinder you a support.

Having the core tube split in two is a lot easier to get green sand cores out of as they are a bit more fragile than bonded cores where springing a single slot apart may work.

[PaulR]

Now if you want that larger engine to perform you will have to start looking into slotted ports rather than the simpler holes that tend to be used on smaller engines This generally allows more steam/air in and out sooner a bit like having a wider slot on a slide valve engine Also conside a couple ofg small blocks between the round port body an dthe end flanges so you don't have to drill the passages very close to the cylinder walls.

In the first photo, does the matching end cover have a notch in the spigot as well?

[Jasonb]

Yes

[PaulR]