Test Tube Stirling

I have the burner mounted in the grill and its ready to be put back together and can actually be used for cooking, well, testing, at this point, but the servo, lcd touch screen, kickassedness etc will have to wait since I'm a bit dead broke and I dont have any of those parts on hand. Ill post about all that in more detail in the next OSGP post. Anyway, I decided to let all of it sit and work on something completely new tonight just for the fun of it and the test tube stirling was the winner. I had already made a displacer piston and attached it to a shaft that was left way long to be finished later when dimensions were established. I have a small scrap aluminum block that measures about 1-3/4"x2"x1" that should work great for the main body/manifold, so I made a committal move and cut the main test tube to length. I decided on 3" OAL, based on the stroke of the displacer, by eye of course. To cut the test tube I wrapped masking tape around the circumference of the test tube where I wanted to cut, chucked it up in the lathe(with god almighty super light pressure) and at about 600 rpms I slowly cut through using a small diamond file. As you can see from the pic it did a great job. I got no cracks and a nice smooth edge that wouldn't cut a baby (while taking the pic of all the parts on the surface plate I knocked it over and put a huge crack around the lip. Not sure if it's fatal, I think I can still work with it, but GOD DAMMIT). 

Here's the pr0n.

I'll take this opportunity to show off my surface plate cover I made from an old shower curtain. Its just as good as the ones you can buy and I think the material is the same too lol.

It sure was a beautiful edge I cut. Just look at how perfect. If I had another test tube this size Id just redo it, but I don't.

If you look at the bottom of the test tube that's standing up you can see the crack I put in it when I knocked it over. But, here are all the pieces I plan to use so far. The black piece is a piece of graphite I turned from square from the art store that I plan to use for a piston. I'm hoping the cracked test tube is gonna work out. Since nearly half it will be permanently epoxied into the aluminum block, I think it might be okay. You cant feel anything with your fingernail if you try to feel the crack. If not Ill be forced to go to the science store and drop $1.50 on a new test tube.

Ill probably use these gears so I don't have to worry about them melting. These are actually novelty steam punk costume gears, not functional in the least, but a half hour with a set of needle files to remove flash and thin bits of metal from in and around the teeth, and they mesh. I believe they'll work just fine. It would be nice to have a stirling operated fan in the grill to create somewhat of a convection grill/smoker. Who knows what all will happen between now and 2025 when the grill is finished? The only way you will ever know is to keep checking here. Besides, you cant find comedy as funny as this.

That's it for this post. Just wanted to take my mind off the grill for a few minutes and play with glass.