Vertical and Horizontal shafts
The view above shows the vertical and horizontal shaft bearings complete except for final reaming. Each horizontal shaft is mounted in six large bearings and one small one. These are to be seen at the back of the image. To the front are the seven vertical shaft bearings. The one at the front, shown the wrong way up, is recessed to take a heavy-duty ball thrust bearing. All these bearing were machined from iron castings by Alf Case.
The drive from the gearbox to the vertical shaft is transmitted by the pair of bevel gears shown bottom right. The three Horizontal shafts are driven through the bevel gear pairs shown on the left. The Horizontal shafts run at 1 1/2 times the vertical with the larger gears mounted on the Vertical shaft. The pair of bevel gears shown top right are for the hand shaft. This can be seen at http://bombe.org.uk/majmlstn3. All bevel gears were made by Ivan Law in his own workshop.
Mounted on the three Horizontal shafts are twelve worms. (Thirteen on the middle bank). The extra one to drive the indictor drum). These drive worm wheels which are fixed with four screws to the ‘diamonds’ shown lower down this page. The diamonds are fitted with two pawls which drive a ratchet fitted to each of the long, upper drum shafts.
This picture shows the quality of finish on a worm wheel. The gears were made in Switzerland under the guidance of Philip Bellamy. Philip also kindly provided the blanks at his own expense.
Please note that some worm wheels are not drilled with the four holes. In addition to the worms on the horizontal shafts there are three pairs on the vertical shaft. These drive the cam shafts etc. In this case the worm wheels are pinned directly to the shafts.
These are the diamonds to which the worm wheels are bolted.