I recently purchased a vega 36" professional lathe duplicator.  The video it came with is somewhat helpful for set up but leaves out anything about synchronizing the duplicator to the work.  I've also had trouble trying to find any instructions on making templates from an already turned piece.  My goal is to duplicate a baseball bat that I made for a friend a few years ago.  He now wants 4 more of the exact copy.  Does anyone have any pointers?  

First of all, Welcome to WR,

 For a duplicator you have two basic settings.  The first is the start point.
The second and more difficult setting is to calibrate the turning diameter.

You will either use an original turning or a template to make a copy.  
A template is traced from the original or generated on your computer and then traced.  
Either way the piece being copied needs to be as perfect as possible.


The horizontal position of elements like beads and coves are nearly automatic but they will look very different from the original if you don't calibrate for the copied diameter.  Your Vega should have instructions on this but here is the basic idea:

 I do this by setting the cutter over the piece to be copied with a known diameter and begin to make cuts on the copy until the diameter is the same as the original. Now with the lathe stopped, and the cutter just touching the copy, adjust the follower to make contact with the original.  The diameter of both should now be equal. Be sure the copier is parallel to the original as the diameter will vary from the original if it is not.

There are other issues to be aware of:
 The shape of the cutter can limit what you can copy.  As an example, if the cutter is pointed, an element like a bead detail with a vertical, 90 degree edge will copy with a slope equal to the cutter angle.  This will require a little hand turning to clean up.

Another issue to be aware of is whip.  A long narrow turning is vulnerable to whipping and will require a traveling steady rest.  Some steady rests mount to the square and are used only with one pass copies.   A one pass copy limits your dept of cut to what can be removed in a single pass.
Another version of a steady rest has rollers like rollerblade wheels that are spring mounted to adapt to a varying diameter and only run on a round surface.  It is surprising how much whip some bat profiles create.

It is generally better to cut down on beads rather than to just drag the cutter over them.
Retract the cutter and start from the top of the bead

Copiers usually have guides at each end to limit the dept of cut so you don't part off the turning with the copier.
You may need to incorporate this into your templates.

Just as with cutting dovetails, making a few copies can be done faster by hand with a little technique than with a machine.
Just not as cool.  Practice with some scrap before mounting a bat blank.

Good luck,

Larry

Bondo, excellent idea for making templates. smiley=thumbsup.gif