Hi Wong;
The Sherline arbor I was talking about is like the endmill holder, but has no hole in it. I looked on the Sherline site, and
see they want $30 for one (!), and they no longer show blank ones.
A2Z makes them for a reasonable $5. They screw onto the spindle nose and you can cut it for whatever size you need.
Made of free machining steel, and is about 1" in diameter. Plenty large enough for 12mm.
http://www.a2zcorp.us/store/Category.asp?Cguid={8B982514-64DD-4D5B-9BA6-020F24000020}&Category=BlankArbor%3ASherlineIf that link breaks, try this:
http://tinyurl.com/37czrjcFor a dog to drive it between centers, something very simple like this will do. You would need one slightly larger
since your cutter is larger. The dovetail cutter shown is 3/4" (19mm) diameter.


For a piece of wood or plastic, I meant that in case you can't rig up some kind of dog driver like the pics above.
You would need a thin piece of wood with a hole in the center, and about twice the size of the end of the dovetail
cutter. Plastic would do, too. It would need to be soft plastic, or rubber. Something the cutting edges of the cutter
could bite into when you pressed it against the face plate. The dead center has to go through the hole to meet the
center hole in the cutter. I think you would do better to make up a small dog out of aluminum. It could just be made
from scrap.
Considering how narrow the dovetail is that you're cutting, you would do better with a smaller cutter, if you can find one.
It's going to barely fit your work piece on the size you got, and that means cutting both sides of the dovetail at once.
Dean