According to John Martin :

Markings: LOFAB 3035

diameter of hole in screw on cover 1.511 inches
diameter at front of taper 1.60 inches
taper depth 2.90 inches
whatever collet it uses will snap into the screw on cover, but there
is no eccentric like one sees on some Erickson type holders

[ ... ]

Not sure what you mean by an eccentric, unless you're talking about the
cam on one of the quick change systems. That doesn't usually work on
the collet, though.

Collet nosepieces like the ones for the Erickson ER series
collets have an eccentric lip which hooks under a groove in the maximum
diameter point of the collets. This eccentric lip allows the collet to
be hooked under it and tilted into the nosepiece, and when you loosen
the nosepiece, it draws the collet out enough so that you don't need to
tap on the back of the workpiece to release it -- unlike the collets
which came with my old Unimat SL-1000 all those years ago.

Enjoy,
DoN.

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