2-1/2 x 3 Simple Engine - Cylinder Castings Set

[DetroiTug]

I would make it as tall as practical to reduce side loading on the crossheads and make the engine more free running. Nothing wrong with weldments, which are actually better than a grey casting. But, cast cylinders are better because they are porous and retain oil.

On the Lococar project, I opted to make (sculpt) some of the cast parts from barstock. For one part, it was easier than making a plug and taking it to the foundry and waiting to get it back etc. And they are stronger.

This forward-reverse handle is made from a piece of barstock.

-Ron

[fredrosse]

Nice work on that lever, almost looks like you used a 12 point Snap-On wrench as a starting point for the lower end.

Weldments to make something like a casting is workable for one-off production, however proper stress relief is necessary if machining the piece for moving machinery like a crosshead. I have put weldments, wrapped in stainless steel foil, into a coal furnace, things get red hot, relax, and if cooled very slowly there are no locked in stresses to distort surfaces when doing final machining. The key here is slow, even heating, and slow, even cooling.

For this engine I already have the crank and connecting rod, so the side loading will be fixed by the length of the conn rod.

[DetroiTug]

Yeah that does look like a box end wrench, I recall thinking that when I was whittling away on it. One of the reasons for using barstock is that a captive spring-loaded detent had to be welded in, it can be seen about halfway up on the back side.

I've been machining weldments for many moons and just about every print called for normalizing, we only occasionally did it though. Only items with a open C-shape of some sort. Like big welded up clevises. Or as you wrote an open frame for crosshead guides is a good candidate.

-Ron

[TahoeSteam]

Fred,

Did you ever finish this engine?

[fredrosse]

Engine cylinder assembly is still sitting on the workbench, I need to get a special part that seems to be impossible at present. Anyone know whereI can get a "round tuit"?

I have been building a house for my daughter, with money from overtime on my day job, very taxing for this old man, who turned 70 a few weeks ago. My son is helping, along with a kind friend sometimes. We now have the building tight to the weather, so progress can now proceed at a more leisurely pace, but I still have to do the drain piping, hot & cold water piping, the electric wiring, heating system, then insulation and sheetrock, fixtures, etc.

[RGSP]

Yeah that does look like a box end wrench, I recall thinking that when I was whittling away on it. One of the reasons for using barstock is that a captive spring-loaded detent had to be welded in, it can be seen about halfway up on the back side.

I've been machining weldments for many moons and just about every print called for normalizing, we only occasionally did it though. Only items with a open C-shape of some sort. Like big welded up clevises. Or as you wrote an open frame for crosshead guides is a good candidate.

-Ron

I'm with Ron on this one. The stresses induced by welding are usually fairly easy to predict, and then decide whether they'll cause problems or not. Usually we can get away with no overt annealing, but in some critical parts it most certainly is needed. I used to do a lot of precision laser welding - gas-tight and mechanically stable welds 0.1mm across - and annealing was very necessary for them, but the easy way of getting enough stress relief was to bend the part until just past its elastic limit in one direction, and then the same the other way round. Crude, but it worked remarkably well when producing hundreds of thousands of the little brutes.

[TahoeSteam]

I can definitely understand the hold up. That's quite commendable of you to build it for her out of your pocket and time. Looks good and energy efficient.

[RGSP]

Good work Fred. In another 550 years it might well look like our house.

[cyberbadger]

Fred/TahoeSteam,

I had never heard of a round "tuit" until now. Absolutely hilarious.

I'm wish I knew about round "tuit" when I had a 3D printer or had access to a pcb photo etching lab...

I printed this in abs which is sort of like a 3d round tuit... - At least just as useful...



-CB

[fredrosse]

RGSP, from England, where wonderful houses several hundred years old are to be found, nice to see your lovely house.

In America, the oldest houses are much younger, and ours is one of the earliest, built 1692, very old for the USA. The right side of the house was built way back then, with a large addition on the left built in 1838. It was going to be torn down, Katharine and I got it for the price of the lot, and it has kept us busy in restoration for nearly 20 years now.