Eccentric Turning Attachment

For Offset Turning on a Woodturning 4-jaw Scroll Chuck

By Ken Grunke

• Fits on any 4-jaw woodturning scroll chuck whose jaws are removable (jaw bases must be flat without protrusions)
• Spindle offset is "dialed in" simply by adjusting the chuck jaws in or out
• Sturdy construction of thick aluminum plate and stressproof steel, precision machined
• Includes one 3/8" screw spindle for holding the workpiece, of hardened steel
• May also be attached to a 4" or larger faceplate if you don't have a scroll chuck, and adjusted manually for offset

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	Shown here attached to my Vicmarc 3 1/2" chuck-- All 4 jaws are removed from the scroll chuck, and the adapter plate is attached to the jaw carriers with hex-head mounting screws through the adapter slots into two opposing jaws.
		~
	Attachment in centered position-- With both mounting screws loosened, the jaws of the chuck are adjusted outwards until the mounting screws reach the outer end of the slots in the adapter. This centers the unit on the chuck.		In full offset position-- either one of the mounting screws is tightened, and the chuck is adjusted inwards. The other screw, being loose, rides in it's slot and is tightened when the desired offset is achieved.
		~	Hardened steel threaded workholding spindle has narrow, sharp threads at a wide pitch of 8 tpi. 12 index marks on the hub allow accurate repositioning of the workpiece at increments of 1/12, 1/6, 1/4, 1/3, and 1/2 of a circle.
	An example of what can be done with the adapter: this will be the top handle for a walking stick. The top section was turned at almost full offset, then the spindle setscrew was loosened and the work was turned 180° to turn the next area below it. Then the adapter was centered as shown and the bottom section where the handle joins the shaft was turned.

Availability of the Eccentric Chuck Adapter

I am fabricating this adapter in small batch runs as raw materials become available. The adapter will be priced at $105.00 plus shipping, and will include one 3/8" screw spindle for workholding. A 1/2" screw spindle will be available for an additional $25.00.
Mounting screws are not included because of the different sizes with various brands of chucks. Vicmarc chucks use screws that are 5 mm dia., and .8 mm thread pitch but I don't know the sizes of other chucks. The screws used to attach the jaws are not long enough, I'd suggest a hex-head screw about 15 mm long, ar about 9/16".

If you really want one of these units, a minimum down payment of $25.00 will ensure delivery within three weeks or less. This is a one-man, limited production show and I will not accept more orders than I can handle in a certain period of time. Everything is machined by hand in my home shop, so I am not ready for production-level orders!
As of Sept. 14, 2007, I have enough material stock to make 4 chuck adapters. I'll keep this site updated with current news.
I do not have any adapters made up, but only need ten days lead time for orders. Please use my contact form to ask about availability and I'll get back to you within 24 hours.