Benefits of Spiral vs Fluted dowel pins
The multiple grooves are more forgiving when pressed into the dowel hole, providing less stress on the wood joint and reducing the risk of splitting.
Spiral grooved dowel pins are considered to be some of the strongest due to the amount of wood that presses against the sides of the hole that the sit in.
What Size of Dowel Pin should I use?
The rule of thumb is the longer the dowel the stronger the joint. Also the diameter of a spiral grooved dowel should not be more than 1/2 of the thickness of the wood.
What size should the hole be?
Care should be taken not to drill the hole too deep to allow water to pool in the bottom of the hole. A standard is that a hole should be 1/8″ longer than the dowel pin itself.
How should the dowel pin be inserted?
The dowel can be manually inserted using a light tap with a rubber mallet.
When should you apply glue?
Filling the hole with standard wood glue before dowelling will provide excellent glue dispersion throughout the grooves of the spiral dowel and create a lasting bond. For better results, after gluing this dowel pin into place use a clamp to hold the wood together. This will prevent the wood from splitting around the hole due to pressure.