- Joined
- Apr 21, 2015
- Messages
- 894
I'm not turning a whole lot of anything in particular. At this point I'm approaching the neighborhood of 100 hours on the lathe.
From a simple physics standpoint, in the case of an independent chuck, more jaws would mean more pressure, assuming each jaw is built with the same strength in each design. Having the jaws directly opposed would also mean that there is (practically) no side force on any when tightening them, whereas there is in a 3-jaw arrangement, though that is offset by the fact that they are tightened simultaneously, virtually eliminating the effect.
With a scroll chuck the torque from the key is divided among the jaws, but at this point I've never seen a time when I couldn't apply more pressure to the key than the jaws could apply to the part. Not sure how to word that any better. I have not, at this point with my limited experience, seen a time when my ability to crank down on a part was the limitation. But in theory even if the two chucks were torqued identically with a torque wrench, while it's mathematically clear that the 4-jaw would apply less force per-jaw than the 3-jaw would, that doesn't mean that less clamping/holding force is applied to the part (again, all else being equal). If anything the addition of one more clamping point should mean increased friction, balanced by the decrease per-jaw, IF we were limited to applying the same torque at the key as we are with the 3-jaw.
Please correct me if I'm wrong but up until the point of damaging the chuck there is no such limitation. In theory. But in theory, capitalism works. Obviously pressing the limits of the chuck is not advisable in any situation, but in normal use there is strength to spare in either design.
From a simple physics standpoint, in the case of an independent chuck, more jaws would mean more pressure, assuming each jaw is built with the same strength in each design. Having the jaws directly opposed would also mean that there is (practically) no side force on any when tightening them, whereas there is in a 3-jaw arrangement, though that is offset by the fact that they are tightened simultaneously, virtually eliminating the effect.
With a scroll chuck the torque from the key is divided among the jaws, but at this point I've never seen a time when I couldn't apply more pressure to the key than the jaws could apply to the part. Not sure how to word that any better. I have not, at this point with my limited experience, seen a time when my ability to crank down on a part was the limitation. But in theory even if the two chucks were torqued identically with a torque wrench, while it's mathematically clear that the 4-jaw would apply less force per-jaw than the 3-jaw would, that doesn't mean that less clamping/holding force is applied to the part (again, all else being equal). If anything the addition of one more clamping point should mean increased friction, balanced by the decrease per-jaw, IF we were limited to applying the same torque at the key as we are with the 3-jaw.
Please correct me if I'm wrong but up until the point of damaging the chuck there is no such limitation. In theory. But in theory, capitalism works. Obviously pressing the limits of the chuck is not advisable in any situation, but in normal use there is strength to spare in either design.
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