CASTINGS
The following is of a casting set I've recently completed for the restoration of a number of Ronaldson and Tippett tractors. The castings are for the replacement of the carburetors, these units where manufactured in the USA in the early 1900's by Zenith. They are an up draught style with three main body sections with a number of small linkage arms. Many of the vintage farm engines found in paddocks and sheds had one thing in common, all the bronze and brass components had either been removed for scrap, or where that badly worn, they were beyond repair. A huge interest has been developed in vintage engine restoration over the past few years. Many of the enthusiasts who restored vintage cars in the past have found the well has dried up. Almost all antique and vintage cars capable of being restored have now been hunted out and brought back to their former glory. The emphasis has now focused on vintage machinery and tractors. As these were not as common as cars at the time, spares are harder to obtain. The only real option is to cast new components from the originals.
Front view of the main body showing the boss where the jets are machined into
Side view
Some of the components for the complete carburetor set.
Various small engine castings.
Wing nuts for shock absorber dampeners on a 1938 BMW motor bike. There was a run of 6 pairs done in both bronze and aluminum. Pattern built-up from the original is in the middle.
Gear change levers for the same bike. Note the risers used to feed the thinner section of the arm. If this was not incorporated the metal on the arm would cool first and shrink 'sucking' the still molten metal from the ball end. Pattern built-up from the original is in the middle.
Bronze gear lever as cast and brushed.
Carby air damper in bronze. As cast and wire brushed.
Pattern built up from the original. Note a chucking spigot has been added to aid machining which is cut off when complete.
Fuel line clack valve. Pattern built-up from the original has extensions added to assist with chucking.
A large loco number plate cast in aluminum measures 800 x 200 x 25 thk.
A set of bevel gears cast from the original. The original was in cast iron, (on the left) the reproduced gears are in silicon bronze. The original gears were badly damaged with a number of teeth missing which had to be built-up and filed back to the profile, a small gauge was made up using some of the good teeth as a template to achieve this. After repairing the teeth, core prints were fitted, draft was machined on the sides and then the surface painted. The total finished cast weight after fettling was around 10kg (22lb). The ring gear is 240mm diameter (9 1/2").
The gears shown are as cast with the gating cut off, next they will be sand blasted and the bores machined to size.
The latest job was a full set of 'J' Class steam loco number plates. Here you can see Spud modeling a weekends casting.
Closer view. The buffer number plate still has the runner and riser attached.