Steam powered tonka truck

[bcharlton]

Is it based on a half or 3/4 ton?

[scalebowler]

Second pic looks like a heavy load....better pump up the shocks!!
Too bad you couldn't make the boiler look like a soda machine!

It does look like that !

That would be pretty cool if I could have made the boiler look like a soda machine. Right now it kind of looks like a pick up truck with a big tank in the back. Will look much better I think once I get the firebox made out of brass and polish it all up.

[scalebowler]

Is it based on a half or 3/4 ton?

I'm actually not really sure if tonka based it off of a half or 3/4 ton truck.

[scalebowler]

Re designed the firebox today and I am quite happy with what I came up with. Origionaly I thought that the firebox was too small and would not heat the boiler enough so I found some pics of the firebox that goes on the engine my boiler was designed for and based off some rough numbers I got from measuring pictures I ended up with the new part. Pretty much I lowered the boiler, widened the box and changed the angles at the top from 45 degrees to 60 and I am quite happy with how it turned out. Now to just figure out where to run the steam line, what to make the vent look like (need an easy to make grate or something so I don't just have a large rectangle hole), and get some brass sheet metal to make it.

[scalebowler]

Got the brass sheet to make the firebox today and allmost all of the fasteners that I need except some nuts and a spring from the hardware store. Hope to get the parts at least layed out tonight or tomorrow. Will pick up the brass rod from grainger tomorrow and will hopefully get the engine all machined on thursday. Hope to finish the truck by the end of next week since all I need to do is finish the engine and then all the rest of the stuff I can do here at home.

[scalebowler]

Well last day to work on the engine for the truck is thrusday so here are the Steam truck goals for thrusday
1. Machine two 3/16” slots on the body of the engine
2. Drill, ream and tap the holes in the axle support
3. Cut, square up and drill square mount block
4. Drill, and ream cylinder
5. Machine and thread top engine post
6. Machine and drill piston
7. Machine, thread and drill adapter for steam inlet

Hopefully I can get everything done in the class period but I think I can do it

[scalebowler]

Ok did not meet all of my goals in the class this morning (hope to try again in my class tonight) but I did make some pretty good progress. I think the biggest thing was that the set up on the milling machine just seems to take so much longer than the lathe. But what I did get done today was I drilled and reamed the cylinder, I drilled and tapped the holes for the axle support, I made almost the entire threaded adapter for the steam inlet (just need to put a 45 degree angle on each side and thread part of it) and I machined the slots in the body of the engine and enlarged and tapped the intake hole. The fun thing was how fast I had to run the drill bits in the machines today. It is kind of fun hearing the machine get up to speed when you have to run them at almost full speed. That lathe had an awesome sound as it was going up to speed

[scalebowler]

well kind of botched the piston so I have to make another one of those when ever I have some free time in class again and I screwed up the pin that holds the engine parts together by making it a few thousands too small when the darn thing was supposed to be press fit in there. Oh well, at least I got most of the engine made

[scalebowler]

Here is what the whole engine assembly looks like. I believe that what happened was when I was making the piston I got a little careless and stupid with the way I did the hole drilling so the piston slightly bent when the drill bit was drilling so the hole is kind of angled so the piston binds when it is about in the middle of the stroke. I am going to ask my teacher about the correct way to machine it so it comes out right and actually runs. Here is a picture of the entire engine. Actually came out not too bad concidering that I had to design almost 50% of the parts myself to make it work in the truck.

[scalebowler]

Here is the firebox for my engine. It was my third attempt as the first one I just cut out the pieces individually but did not like the idea of connecting them with rivets and having those show so I made another one but that was about .020" too wide so it did not fit into the back of the truck and just scrapped all the paint off the bed so I took .020" off of all the widths and came up with this one. Not exaclty sure why it is taller than the prototype since I followed all of the measurements on the drawing but it should work so I am not complaining. Since the inside and left, right and back sides won't show I don't really care that they are a little scuffed up or have some rough edges (inside) but for the front I do plan to hit them with a little super fine grit sand paper and then some never dull to make it look a little better.