rockler dovetail jig

1) Use the 7/16" bushing, Start on the left side of the jig, and keep the bushing against the left side of the finger when pushing the router in, and against the right side of the finger on the way out. (Keep the bushing against the comb at all times), and make sure that the comb is laying flat against the top of the horizontal board.
2) You will want your bit to cut a path approx 7/16" deep to start.
3) Raising the bit will make the teeth left on the vertical board smaller, lowering the bit (deeper cut) will make them larger. It will likely take a few attempts to get this right. You can only cut them once. if they are wrong, cut the board shorter and try again. Once you get it right, you might want to take a piece of scrap and put it in the jig vertically. make your cut as if you intend to use this board, and then set it aside. Use this as your depth guide to get you close next time you put the bit in the router.
4) You will have to set your stops so you can align your boards right. When the horizontal board is in place, the left edge of your board (as shown in your picture) should be centered in the groove of the comb, and the left edge of the vertical board should be centered on the finger located just to the right of the groove.once the boards are in place, adjust the stops on the jig against the left edges of both boards so you can duplicate the set-up quicker next time. After you have adjusted the left side stops, you'll need to do the same thing on the right side of the jig with the vertical board offset towards the center.
5) Once you are happy with all of the above, you may have to move the comb forward or back in the jig to adjust the depth of the joint when you put the boards together. If the grooves in the horizontal board aren't deep enough, the comb should be positioned farther in toward the body of the jig. This adjustment will be 1/2 of the distance you need. If you move the position of the comb by 1/16", it will show up as 1/8" of placement when you put the joint together.

Hi Joe

Not trying to be a smart ass ,but you need to start over at sq.one.
Just trying to help

Down load the user manual (PDF guide) from Harbor Freight and read it over a time or two.
It will show you how to make the dovetails that will come out right the 1st. time and every time after.

Manual below
http://www.harborfreight.com/cpi/ctaf/manuals.taf?f=form&ItemID=34102

The key is to keep all the stock the same size (thick) MDF is a good one to used for the 1st time because it's a true size.
Besure to mark the stock with A,B,C,D it will help plus put s X on the stock to show the inside of the box.
Plus put the stock edge under the 1st. pin (in the center of the 1st pin) and always use the same router when you do dovetails and set the stop bar for that router.
Most don't put dovetails on the front and back just the front and the sides but the jig will do both and do it very well but it's bit ticky to setup.

Plus you may want to read the link below.
Small error in this type of dovetail jig but you can fix it quick and easy. (see link and snapshot /pictures)
The Error=the finger part of the jig will move just a bit when you clamp the stock down, that's to say it will move to the right or the left and this will off set the joint and with a dovetail joint it must be dead on....
You will not see it until you put the joint together,one will be high or low,by 1/16" the norm.
http://www.routerforums.com/showthread.php?t=1555

Just a side NOTE
The box jig(s) that Oak-Park sells are great for what you want to do.
You don't need to use your rubber ruler ,if you want a box that's 11" wide and 20" long that's what you cut the stock for, quick and easy ,then put the slot in for the bottom then but a face plate on the front and your done.
Plus it can be from 1 1/2" to 48" tall unlike the norm. jigs.

http://us.oak-park.com/catalogue.html?list=boxj--
http://www.routerworkshop.com/boxjoints.html

Hope this helps
Bj