Hi Guys,
I searched HMEM for bearing preload but the search came up empty. I think I am using the right term. My Chinese 250mm X 550mm lathe is a very basic machine. On the drive end of the spindle it is threaded M27 X 1.5mm and fitted with 2 nuts (the kind you use a C spanner for ) which put pressure on the spindle pulley which presses against the 40t gear which in turn bears against a thrust collar which preloads the 2 taper roller spindle bearings. The pulley, gear and thrust collar are a sliding fit on the spindle, the pulley and gear keyed to the spindle. I suspect that many lathes have a similar arrangement.
Of course when I removed the pulley to try for a slower speed I upset the preload as delivered. Now I need to know just how tight or loose must the spindle tension be, and how do you measure it? Do you use the same preload under all conditions of speed, depth of cut, mass of workpiece, etc?
Thanking you again and hoping you dont tire of my questions,
Ant
I searched HMEM for bearing preload but the search came up empty. I think I am using the right term. My Chinese 250mm X 550mm lathe is a very basic machine. On the drive end of the spindle it is threaded M27 X 1.5mm and fitted with 2 nuts (the kind you use a C spanner for ) which put pressure on the spindle pulley which presses against the 40t gear which in turn bears against a thrust collar which preloads the 2 taper roller spindle bearings. The pulley, gear and thrust collar are a sliding fit on the spindle, the pulley and gear keyed to the spindle. I suspect that many lathes have a similar arrangement.
Of course when I removed the pulley to try for a slower speed I upset the preload as delivered. Now I need to know just how tight or loose must the spindle tension be, and how do you measure it? Do you use the same preload under all conditions of speed, depth of cut, mass of workpiece, etc?
Thanking you again and hoping you dont tire of my questions,
Ant