Matthew Murray's Rack Locomotive of 1812 for the Middleton Railway: Anthony Mount tackles the cylinders, the most complex parts of the engine. PART 7

摘要

Due to the small size of the cylinders (Part 46) and the passageways, it seemed that a fabricated cylinder would be easier to produce than to try and use a casting. Two lengths of continuous cast bronze bar, nominally 32mm dia., are required. Set up to run true in the 4-jaw independent chuck, we are using the independent as the surface of the cast bronze bar though smooth is not that accurate. Machine to length but leave 0.5mm long for the time being turning down for a length of 42mm to finish at 32mm diameter. Reverse and position the bar in the 4-jaw independent chuck offset by 2.75 millimetres. If you rotate the bar until the maximum eccentricity is facing you and feed in the dial until it touches the work and then zero the dial, on turning the chuck through 180deg. the cross slide needs to go through 5.5mm of travel until it touches the bar, the setup can be seen in photo 37.