Tip: Making the plugs
Make the plugs out of 18mm (3/4") diameter wood dowel. 36 plugs are required altogether although a few extra for future plug loss would be advisable. Forty 75mm (3") plugs can be made from a 3000mm (10ft) length of dowel.

Taper the plugs by holding a full length of dowel in a turning motion against a belt sander. Once the end of the dowel is tapered to the dimensions as shown in the above plan, then cut 75mm (3") off the end of the dowel length. The first plug is made. Repeat the sanding and cutting action until all the plugs are made.