By Jason Ballamy 
Part fifteen - Cart continued
M4. C4n

With the wheels out of the way it is time to start work on the actual cart starting with the front bolster. The top corners are rebated so that the angle iron sides will sit flush, the bottom curved to allow the axle to articulate and the pin in the middle allows the axle to pivot, this is the basic sketch.

The various bits of steel were cut to size, I used 3mm angle at the ends as I needed the internal radius and the bottom curved part was a section of 100mm x 3mm wall steel tube.
As there were going to be a lot of parts to try and hold together for silver soldering I decided to fabricate the lower parts by welding, I'm not the world’s best but with a bit of fettling it came out OK.
After silver soldering a bit of file work had things looking the right sort of shape and I also milled out the slots where the angles bolt to the sides.
The two inner webs were marked out by holding the job ontop of a blued sheet of 2mm steel and just scribing the shape. These were then coated around the joint with soft solder paste and a few spacers parted off from some aluminium rod to stop them dropping through during heating.
After a bit of a clean up we have the finished bolster, you can see why I wanted the internal radius of the angle iron as it allowed me to round the outer corner and still keep the same wall thickness.
Next up is the front axle casting.
The parts that the spindle passes through were straightforward turning jobs and I printed my drawing out as a guide for bending the top flange.
The lower flange was bent from some 5/8" x 1/8" flat bar and the two ends welded on.
The main central web which is thicker in the middle was shaped from some 1/2" square and then the whole lot silver soldered.
So that the axle can both steer and pivot it required a hole that was 7/16" round at the top but opening out to an oval at the bottom, to do this I mounted the work on the rotary table with the parts top surface dead on centre height and milled it 10degrees either side of vertical.
The end webs were added in the same way as the bolster then after a bit of a clean up and some primer it looked like this.