General Processes - Jointing Multiple Layers with Multiple Dowels

Example using a Typical Photo Frame Project:

You want to join a piece of clear acrylic to a wood with 4 dowels to make a photo frame. So that the clear acrylic cover can be removed to add or change photos. You want to place one dowel in each corner. How do you install the dowels and make sure all the holes are aligned?

Note: This section assumes that the student is able to prepare and get ready the wood and acrylic material for the next stage. It also assumes that the student is able to mark out both wood and acrylic proficiently.

Step 1: (Marking Out)

• Use double-sided tape to tape the acrylic sheet to the wood.
• Avoid taping where the holes will be drilled.
• Mark out the positions for each of the 4 holes with an 'x'.

Step 2: (Preparation to drill)

• By now you should have worked out the length of each dowels based on the thickness of your wood and acrylic.
• If the diameter of each of your dowels is 6mm, the get ready a 6mm diameter drill bit.
• Install the drill bit to the drilling machine.
• Get ready 4 dowels that is already cut to length.

How to get the length of each dowels?

• 2/3 the thickness of the wood + thickness of acrylic sheet + how much you want the dowel to protrude out of the acrylic sheet.

Tips:

• If you are unsure if your dowels will be tight fit on your photo frame, test using waste acrylic and wood. (see step 1 for preparation)

Step 3: (Drilling Procedure)

• Secure your combined work piece (see step 1) on the drilling machine with an F-Clamp.
• Set the drill bit to the required depth.
• (To drill a through hole, see 'tips' just below this step)
• Drill the first hole and install a dowel.
• Drill the second hole diagonal to the first hole and install a second dowel.
• Repeat the process until all holes are drilled.

To appreciate why you need to do the above, mark out and try drilling four holes individually on an acrylic sheet and wood one after the other. Put them together and try putting in the second dowel. How's that?

Tips:

• If you plan to drill through the holes, i.e. you want to expose the dowels on the other end of your photo frame, you need to place a piece of waste wood below your workpiece. Drill through your workpiece into the waste wood.
• This is to minimize splitting (on the wood part) at the other end of the drilled hole.

To appreciate why you need to do the above, try clamp a waste wood suspended on a machine vice without a waste wood below. Drill through. You will know what I mean.

Step 4: (Finishing)

• Split both the clear acrylic cover and the wood for finishing separately.
• Finish both the clear acrylic cover and the wood respectively with your desired finish.

The end.