Now this is not your mother's little doweling jig, this is built like a tank and a very good tank at that.
When you get it and open the box you say no way, that is just to big and heavy, but once you start to use it, its a whole new ball game. It is very easy to use and the size and weight are just fine. It is very accurate, spot on every time.
It works much like a DowelMax, you have a reference plate and each end is a reference surface. As long as you are using those references you just can't go wrong.
In use it is very easy to use, place it on the board, line up the edge with an end and drill your holes. It can be used on the edge of a board, the face of a board or in the middle of a large board. One of the really nice things is you do not have to use shims to get it set the way you want it. There is a scale on the side that shows you just how far the edge is from the center of the whole.
So you measure the width of your board and then divided it in half and set the scale on the side for that. So with a 3/4 in board you would set the scale at 3/8 and this will put the hole in the center. But if your board is not exactly 3/4 no problem, you will be using the reference surface for all your holes and this will make sure they line up.
To change from edge to face just unscrew the Allen screws from the locking plate and then screw it to the bottom of the reference plate and you are set to go.
If you need to put some holes in the middle of a large board, no problem. Unscrew both the reference plate and the clamp plate and you can just line it up with the center mark on the unit. The one pictured on the Jessem web site does not have the center line, this was added after the pictures were take and will be on every unit they sell.
The knobs that tighten it down are big and easy on your fingers. It does come with a plug for spacing and also a set of rods so you can do indexing. From emails to Jessem this my be changed in the future to a single rod. The two rod system is not as handy as a single rod in that it is a little harder to change and move from one side to the other. To change the indexing now and keep the setting you must loosen one set screw and unscrew one rod, then rotate the stop bracket and rod at the same time, then do the same in reverse to put it on the other side.
Overall, I really like it, it is large and has weight to it but as a said, this is not a problem, in fact it is nice to have that weight at times.