Step 1: Locate peg holes
These chucks have a 1/2 - 20 mount thread, I had a 7/16 wood dowel from another project for this lathe, which fit perfectly through the center hole. I got a scrap piece of MDF, using a combination square, I found the length wise center and made a line. Where I decided to place the pegs for the chucks, I used the combination square to draw a line perpendicular to the length line.
Then, I placed the MDF into my drill vise, centered over the crossed lines and drilled.
Note: I know the distance between the first and second peg from left is off. I accidentally put the three jaw chuck next, instead of the second jacobs chuck, when I measured for the second peg, so pay attention when you're doing this.
Step 2: Measure and cut
For the jacobs chuck, I pushed the rod to the stop and made a mark with my finger nail flush with the end of the chuck. Next, I placed the rod next to the MDF, so that the mark was at one side of the board, and made a mark on the rod to allow for the thickness of the board.
Next, I clamped the rod in a miter box and cut.
For the three jaw and four jaw, I put the rod flush with the face of the jaw and made a mark with my finger nail flush with the backplate of the chuck. I repeated the method for allowing for the thickness of the board and cutting the rod.