24-05-2018, 08:06 AM
If nothing else a graphic illustration of the remarkable properties of cast iron. From the photos the mesh angle is suspicious but with so much wear anything likely*. All we need now is for someone to announce they have used SAE30 API SA or Mobil One or somesuch and no wear! I have seen Sevens with an external oil feed to the gear and with double the input power may be worthwhile. Few appreciate the significance of the feed groove.
Skew gear use and the operating condition is so unusual one would reasonably expect whoever cut the gears to question the material. I guess the UK is no longer a land of craftsmen.
*(In the early 1970s I purchased a new Indian lathe from catalogue. Everything was abysmal. The artisans that made it were apparently still transitioning from bow lathes. File finish of spindles and all grossly mis aligned. The helical backgears are cut to slightly different angles and engage on the very end of the teeth. Fortunately not required to do heavy work..The leadscrew was ¼ higher at one end than the other. But the key element of a lathe, the bed, is straight, sufficiently so with a lot of tinkering to rebore cyl liners)
Skew gear use and the operating condition is so unusual one would reasonably expect whoever cut the gears to question the material. I guess the UK is no longer a land of craftsmen.
*(In the early 1970s I purchased a new Indian lathe from catalogue. Everything was abysmal. The artisans that made it were apparently still transitioning from bow lathes. File finish of spindles and all grossly mis aligned. The helical backgears are cut to slightly different angles and engage on the very end of the teeth. Fortunately not required to do heavy work..The leadscrew was ¼ higher at one end than the other. But the key element of a lathe, the bed, is straight, sufficiently so with a lot of tinkering to rebore cyl liners)