As a couple of people have asked to see the rig, here are some pictures…
Please keep in mind that any off-centre rig is only as safe as you make it. All fixings should be double checked, and checked periodically throughout the period you are using it. Keep all objects, tools, and more importantly limbs and digits, WELL away.
For this jig with the particular piece of wood in question I used 9 * #14 double-helix screws, and was certain that they were well into solid wood.
The turning speed was 300 RPM (with a lathe that has “soft start”), and was increased to 900 after some of the weight was removed.
Full face protection was worn throughout the turning, and periodic stops to rest and check fixings.
The faceplate ring was welded on by a professional certified welder, and it has a dovetail shape to fit the jaws of the scroll chuck. The large plates for counter balance are fixed with two 24mm bolts.
The lathe which held this rig is a Wivamac DB1200 with full factory-built off-bed kit.