Wheels for Clayton Steam Wagon

[dnalot]

This morning at 8:00Am I started with an AutoCAD drawing of a wheel and by 2:00Pm I had a rough casting to machine two wheels from. Now I don't normally like lost foam casting as I have never had much success at it but I wanted to try something different. Instead of coating with vestment or using play box sand, I used normal petro bond casting sand and rammed the foam part gently in the sand. The parts turned out just fine, no smother or rougher than the foam part I started with. One wheel had a little shrinkage around the middle of the rim but there was plenty of extra material there. The wheel blank is 6" in diameter and weighs 5.5 pounds. The machined wheel should weigh about 3 pounds.
I made these parts as a test to see if I am up to building the "Clayton Steam Wagon" The wheels and tires looked like the hardest part so I decided if they turn out OK I would go ahead with the rest. Every surface on the casting will be machined and I plan on casting the hard rubber tires in place. These castings are for the rear dual wheels.
I cut the foam using a CNC router and used a cardboard tube for the form. What I learned from this is pour the metal fast to overcome the back venting "I did poke 8 vent holes to the outer rim after the sand was rammed" and provide a good Head.
My expectations were very low so I was easily pleased with the results.

Mark T

 

[chipenter]

You are right about the wheels I made mine from mild steel brazed together , and took a lot of work to do , the fire box is very small and it was tricky to control the fire , when I got it to steam it was powerful and could pull quite a load .

 

[Jasonb]

Nice wheels but I have two questions

Why did you leave material between the spokes?

Why make the spokes flush with the rim and needing machining back?

I would have thought the whole idea of the lost foam is that the part can be drawn and cut the the finished shape allowing for shrinkage and any machining allowance where required. So the spokes should not need any further work.

 

[dnalot]

[Why did you leave material between the spokes?

Why make the spokes flush with the rim and needing machining back?/QUOTE]

Ramming the foam part in sand was difficult to do without distorting the foam. If I left out the web between the spokes they would move when rammed and when I tried to recess the hub and spokes I was not able to support the foam for ramming. As I only wanted a piece of stock that would only need minor machining I kept it Simple. After I turn the wheel to diameter and face the wheel to the proper width My CNC router will make quick work of detailing the spokes. Before I make the front wheels I will get some denser foam and try to make the part more detailed. Its a learning experience.

For those who haven't tried CNC programming, Its very easy and fast to do 2.5D from a simple 2D drawing. It takes a lot more time to make a 3D model for the Cam program to work with.


Mark T

 

[Jasonb]

Thanks, I can see why now if the foam is a bit soft and the CNC machining will do the rest.

J

 

[dnalot]

Just to follow up, here is a photo of a Wheel after machining. I should have cast the hub with a hole in it as there was a bit of nastiness in the center and there was a little to much shrinkage. I also over did it on the diameter of the rough casting. I now have both rear wheels completed to this stage so now its time to start machining the smaller front wheels.

 

[zaneiel]

That is amazing, simply beautiful work!

 

[tatt2s4don]

I will say
I have learned a lot on this app between you good people just reading what folks have to post about good / bad IDEAS !
Keep up good work



Sent from my iPhone using Model Engines

 

[johnmcc69]

Very cool! Nice looking wheels!

John

 

[dnalot]

Hi

I will be updating this thread very soon. I have the frame and axle groups completed and yesterday I cast my first tire. Turned out great except for a big bubble. Now I need to order more material to cast all six tires (less the bubble). When I have a rolling frame I will post some photos and show how to cast tires or other rubber parts.

Mark T

 

[dnalot]

So its back to the Clayton project. Today I will show how I cast solid rubber tires.

After an exhaustive search for an easy way to put some tires on my wheels I finally decided I would have to cast my own. A search of McMaster-Carr for rubber casting materials found me this product. Liquid urethane, it was available in several grades of hardness. It is a two part mix that vulcanizes at room temp.

The form I made from some plastic material that boat builders use. The product was called "Star Board" and it machines very nicely and nothing will stick to it. To determine how much material to mix I filled the forms with water and then poured the water into a mixing cup and marked it. The forms were placed in a vacuum bag for the pour. The urethane base is thick like cold syrup, it needs to be mixed VERY well or you will have soft and hard spots. The mix is by weight so I used a gram scale to measure out the material. MIX MIX MIX scrape the stick and the sides of the cup Mix Mix Mix some more and then repeat. As I started pouring the material into the form I applied a little vacuum to help pull in the thick mess. Once the forms were full I turned off the vacuum pump. It takes about 30 min. for the stuff to start to set. I kept tapping the forms during this time and a few big bubbles came out. There were some smaller bubbles that were trapped near the top of the form and they became apparent when I sanded the tire to give them a road worn look. They are small and I'm not going to worry about them. I let the forms set over night and parted the forms the next morning. The material takes about a week to come to full hardness. After a few days I stretched them onto the wheels using the same material to glue them in place. An interesting note: Lock tight-green-680 can be used to glue the urethane as well. It took three 1 QT kits so the tires were not cheap, but the scrap aluminum I made the wheels from was free so the cost of the Tires & Wheels was acceptable. The shelf life of the urethane kit is very short, about 3 months; less if the can has been opened. If you don't follow the mixing instructions and change the ratio of part A to B you can start a fire or get a mix that never cures. The product is very flexible and durable; one suggested use was for repairing conveyer belts.

The wheel is black but to get any detail to show in the photo I had to overexpose the image. The wheels were anodized and dipped in black die. After sealing them I then sprayed them with a polyurethane semi gloss.

Mark T

 

[dnalot]

Before I started this part of the project I knew what a differential did, I just never thought about how it worked…. After a little study time I now realize there are a lot of ways to make a differential. I have not yet learned how to make gears so I bought some that would need to be modified a little. They are brass and I hope they will work. If not I will need to make my own someday from steel.

The axle was turned from a 1.5" x 18" piece of steel and my modified ring gears were soldered in place. The carrier for the pinion gears I made from aluminum and the sprocket was store bought and made to fit the carrier. Once assembled the gears were a tad bit stiff and lumpy so I put the assembly on a lathe and dabbed a little 600 grid lapping compound on the gears. A few minutes at 28 RPM and the gears were running butter smooth.
After everything was made and fitted, I "Parkerized" (got it right this time) the steel parts. The hubcaps I made from steel and then copper plated them. I think I will add a bronze plating bucket to my collection and bronze plate them before I'm through. The wheel is held in place by a ring with a pin through it. The pin is retained by the hubcap. And the hubcap is held in place by a very thin magnet. It takes a lot of effort to bull the hubcap off.

Next I will show the frame and the springs and put what I have built so far all together.

Mark T

 

[jschoenly]

Really nice work!!

 

[dnalot]

Spring happened and I have not been as active in the shop of late. But here is an update on the Clayton project.

The model's design plan called for mild steel "fake" springs. I wanted real springs so I used spring steel. It is still very stiff so I made the rear springs with three leafs active for a soft suspension and the rest come into play as an overload set. Like the rest of the running gear the finish is Parkerized and oiled.

The engine has been rather difficult but I have finally gotten the lower end completed and turning over smoothly. This is my third engine and I have learned to make my parts a tight fit and then lap them to perfection. I lapped my ass off on this one. The crankcase is made of mild steel sheet soldered together. I used a 70 percent tin and 30 percent lead solder to assemble and then followed up with a lower melting temp solder to seal up all joints, this is a wet crankcase. That part went fine and the case is very robust. All the internal parts are of mild steel with bronze bushings and blocks. The plan showed an assembled crankshaft but I went with a solid one piece unit. The crank was turned from a 1.5 inch square stock "4130". After removing most of the material I let it sit for a few days to settle down before doing the final turn. (The black stuff on crankshaft in the photo is from some electrical tape that secured the Jacks between the webs) Getting all the linkages for the joy valve system to clear one another was a real job. I spent more time fiddling with the parts than I did making them. The three gears that will power the water pump's eccentric were salvaged from an old optical scanner. On my next project I want to learn to cut gears (thinking about making a Minnie Traction Engine). I'm going for a gnarly looking old engine so I copper plated the crankcase and aged the copper and bronze parts. I now have all the top end parts cast in bronze but I need to do the cylinder block over, it has a lot of porosity. The top end should be little or no problem so my mind is wandering off thinking about the boiler.

I painted the frame with an etching primer. I liked the color so I top coated it with a spray on polyurethane.

My next update will have a video of the engine running on air "I hope"

Mark T

 

[dnalot]

And one more photo that didn''t fir in the last post.

Mark T

 

[dnalot]

Well it has been a while since I updated this thread. I love building the models, doing the work to post not so much.

So I took the spring and summer of 2014 off and played outside and when fall came I went back to work on the Clayton. Up to this point I have followed the plan but now it’s time to make some changes. The original plan called for a trailer so the truck could pull some fat old man around. I opted for a flat bed with drop sides. The others change was to fire the boiler with propane gas rather than coal. To do that I needed to hide a gas bottle somewhere. The water tank was the best option as the gas bottle with its valve was exactly the same width as the truck’s body. I plan to cover over the ends with hose reels. One side will have a hose for filling the water tank and the other will have a hose for steam cleaning. I made my tank a little larger than the original model had and I opted to mount it a little cleaner. The cab was built to the original plan.

I am now wrapping up the boiler construction and will post a few photos as soon as its completed and mounted to the frame. Until then I have included a photo of the truck painted with the unfinished boiler in place.

Mark T

 

[barnesrickw]

Very cool.

 

[kjk]

Beautiful work. How did you locate the rough rear wheel castings for machining on the cnc router?

 

[dnalot]

How did you locate the rough rear wheel castings for machining on the cnc router?

I made them. First photo on the first page shows the blue foam I cut on a cnc router. I used the lost foam method to cast them. I made the wheels first because they looked like the hardest parts to make. This has been an epic build and I have been overwhelmed at times. But as I near the end I am already itching to start building a 1.75" Minnie.

Mark T

 

[mikegw1961]

Mark
You have made a lovely job of the Clayton. I am trying to draw the Clayton in solid works at the moment and I am using the model engineer articles but I cannot find any ref to the slide shaft bearings. Do yo have the details of the bearings or can you tell me where you found the details.

Mike