dorkpunch Engines- 2 cylinder Wobbler.

If you go back aways, you'll see the wobbler air engine I have my 8th grade students build in Metals 2.  Well, I've been working on another version of it.  Pretty simple really- just welded another valve plate on the opposite side, added another cylinder and piston, and cut the pistons so they can share the same crank pin.

Works okay, but still needs some tweaking.  Will run fairly slow but if I try and crank up the speed, it seems to be fighting itself and won't rev way out like the single cylinder version does.

Fun to play with, anyways!

dorkpunch engines #3: Boring the cylinder.

I had some time to kill at the shop while waiting for my wife. She said she would be over in half an hour, which of course means 2 hours. She even ran a little late so it was more like 2 and half so I was able to knock some holes in some aluminum.

1/8" pilot holes, 3" deep through the cylinder. The two for the valves are the finished diameter for the valve guides. The cylinder has a long ways to go... 7/8" more to be exact.



To drill them I had to use a big 'ole aircraft drill. Started with a normal drill bit, got as deep as it could go, then switched to this long one. Figured there was less chance of the holes going crooked on me.



Makin' chips.





Makin' BIG chips...



and big messes.



"Finished" cylinder. The drill bit is obviously a bit rough, so I plan to hone it with a brake master hone and then match the piston to the finished bore.



Because of the vice I was using, I couldn't drill all the way through. This is not a problem though, because I still need to machine off about 1/4" to get it down to the stroke I want.



Bottom.



Will hopefully start doing some figuring on where the valve ports need to go and the final diameter of the valve heads.

Thinking I should have left the bore a tad smaller- its pretty close to some of head bolt holes. Won't have a lot of gasket area in those two spots.

Live and learn...

dorkpunch engines #2- Cylinder and Head.

Back to our home built hit and miss engine model.  Here's what we're starting with:




Ordered all of these on ebay.  Need to check and see what the alloy is, but whatever it is its darn soft and machine very easily.

Makin' chips.



This is a shakedown run- testing how much I've forgotten since college and seeing how sucky this lathe really is. Turns out I don't remember much...   It also turns out that my lathe needed some tweaking but I didn't figure that out until later.  *sigh*

Machined it down, lazily marked a few spots and drilled some holes.



Countersunk.



Parting off the head. Took FOREVER. Need to align the tool- sits too low.



Head and cylinder.


Tapped the holes.



Teensy plug I'll be using:



Fits together quite nicely!





Plan is to use some soft copper sheet I have as a gasket. Now the hard part begins- figuring out how to get the piston and valves in there.

So far this is LOTSA fun- many things are starting to come back to me.  Really enjoying being able to make chips fly, but I've got a loonnngggg ways to go before its up to par.

Lego Engines!

Try this on for size! This was built by one of my 7th grade students. It's powered by a Lego Mindstorms NXT and actually runs pretty darn smoothley!



Square piston and crankshaft.



Interesting spoked flywheel and the "electric start".



Intake / exhaust port at the bottom of the cylinder.



Video of it in action!



He said he just kinda started putting stuff together and this is what came out of it. Very impressive!


Now, I could have sworn I posted this one somewhere but can't seem to find it... So here it is (again?).

This was built by one of my 8th grade students that was also building my wobbler air engine.  Same story- he was playing with legos and this sort of emerged from the chaos.  This one even RUNS on compressed air.  It takes a LOT of it though-  lots of leaks through all the gaps.







Kind of hard to see but if you look to the right of the little square lego piece you can see the air intake port.



And of course a video of it in action!

dorkpunch Engines #1. (re) Learning how to machine.

So I stumbled across this video a while ago.



I've been wanting to try my hand at making some type of miniature model engine for a long time now. I have seen dozens of these cool videos- in fact, here are two more.






I've built a couple of really simple air engines, and even use the one as a project for my Grade 8 students to build.  Here was my first attempt ever at building an engine. This was my test bed for the above engine- basically copied but simplified from one I found on Instructables.





I adapted that one to this one- VERY simple to make and pretty easy to get running decently. ZERO machining- all done on a drill press or with hand tools. Little bit of welding but it could be done without it if you had different chunks of metal.

From this:



To this:







Back to the topic at hand.  I've got my own idea I've been kicking around for a while- flathead with an atmospheric intake valve, 1" bore and I'm thinking either 1.25 or 1.5" stroke. Not sure how I'm going to do the governor but I've got a few ideas. No idea how well it will work, if it ever even DOES. I don't have a real great track record at finishing projects...

Been working on dumping the ideas swirling around in my head out onto paper and the computer.

Here's the general idea.









Currently thinking flathead, with atmospheric intake valve. Main design constraints are the limiting factors of the tools I have, so the goal is to make it as simple as possible and entirely built on the tools I have access to- a Smith 1250xl (?) lathe / mill combo. Been playing around a bit and have made some shavings, will get more pics posted.