Doweling has been around as long as there have been woodworkers. It has fallen out of favor with the advent of powered machines, better adhesives and mechanical joinery options. Still there is a certain visual appeal of the end of a dowel on the face of a joint.
Miller dowels are different than regular dowels as they are engineered to install easier, self align, and hold better. They are stepped dowels that allow easy alignment when making a butt joint. The main holding power comes from the ribbed sections. They work by holding more glue in gaps that really grabs the end grain. Also the ribs are pressed in so when the glue is applied, it slowly swells that part of dowel. This slow swelling allows easy installation while slowly making a compression fit after inserted in the hole. These dowels come in three different sizes and come in several different species of hardwood.. They require a specific drill bit for each size. The bits are a bit pricey but you buy them once. For more information go to their website.
Naturally, these dowels leaves a plugged look, which you can use to your decorative advantage by choosing a contrasting species of dowel. Miller Dowels come in three sizes: 1X dowels are 2-5/8" long with 3/8"-diameter heads; 2X dowels (3-3/8" long) have 1/2" heads; and Mini-X (1-5/8" long) have 1/4" heads
The project I am making is some cantilevered selves. Since the wood is 1" thick I will use 1X dowels. I will use birch dowels because it is what I have on hand.
Step 1: Drill Stepped Pilot Hole
Mark where you want the bits and drill the stepped holes. Note that I am drilling at an angle. With the dowels placed are opposing angles their is no way the pieces can separate. The dowels would break before this joint would fail. (This trick also works with nails.)
Step 2: Glue and Install Dowels
You will only need to apply glue on the ribbed sections. This means it will go in with little mess so be generous with the glue. Then tap the dowel in with a mallet. If you do not have a mallet then use a hammer but use a piece of scrap wood to protect the dowel from hammer damage.
Step 3: Trim and Sand
Use a flush cutting saw to trim the dowel and then sand with 100 grit sandpaper until completely flush.
Before switching to 150 grit, put a little glue on the joint, quickly wipe it off, and immediately sand. When you sand the dust will stick to the glue that left in any small gaps. Final sanding is done with 220 grit.