I purchased a D1-3 camlock backplate and an ER32 chuck about a year ago and finally got around to mating them for use on my M250.
The backplate has burrs on all the machined edges, a tiny machining allowance for the chuck mounting and studs that are quite different to a Pratt Burnerd 3-jaw that came with the lathe, photo below with the PB on the left.
D1-3 Stud Comparison compr.JPG
The differences in thread, finish and lengths of the studs are not, in themselves, a concern but the finished inserted dimensions are.
The PB studs fit to the chuck with the outer edge of the scallop 24.5 mm from the flat mounting surface.
Each stud has two turns of adjustment available to handle any future wear and stretching.
The chuck fits on the spindle with the cams locked tight nicely midway between the two marked limits.
The new studs, when inserted to the limit of the thread,have the outer edge of the scallop 25.5 mm from the flat mounting surface.
The studs have no available turns available for future wear etc.
The backplate fits on the spindle with the cams locking past the maximum marked limit.
And this is with the backplate still carrying the burrs which, when removed, would make the fit worse.
What to do ?
I think the correct approach will be to machine the stud counterbores to achieve the 24.5 mm dimension with two turns available for the future, 3 mm for the M10 x 1.0 thread.
An alternative could be to source alternative studs.
Comments welcomed.
John.
The backplate has burrs on all the machined edges, a tiny machining allowance for the chuck mounting and studs that are quite different to a Pratt Burnerd 3-jaw that came with the lathe, photo below with the PB on the left.
D1-3 Stud Comparison compr.JPG
The differences in thread, finish and lengths of the studs are not, in themselves, a concern but the finished inserted dimensions are.
The PB studs fit to the chuck with the outer edge of the scallop 24.5 mm from the flat mounting surface.
Each stud has two turns of adjustment available to handle any future wear and stretching.
The chuck fits on the spindle with the cams locked tight nicely midway between the two marked limits.
The new studs, when inserted to the limit of the thread,have the outer edge of the scallop 25.5 mm from the flat mounting surface.
The studs have no available turns available for future wear etc.
The backplate fits on the spindle with the cams locking past the maximum marked limit.
And this is with the backplate still carrying the burrs which, when removed, would make the fit worse.
What to do ?
I think the correct approach will be to machine the stud counterbores to achieve the 24.5 mm dimension with two turns available for the future, 3 mm for the M10 x 1.0 thread.
An alternative could be to source alternative studs.
Comments welcomed.
John.
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