re: Mortise and tenon

MontyJ:

I’ve included below a write-up on how I make tenons – it sounds much more complicated than it is.

I use the Domino Tool for virtually all of my M&Ts, and routinely make #10 (mm), #8 and #6 – my recent DVD Holder required #4 (mm) tenons, and the following process works for each one. The benefit of the Dominos is they have set width dimensions – and can be sized in normal, wide, and x/wide.
Making Tenons:
My procedure is to start with straight-grain hardwood from the scrap wood pile which is thick enough to fill the mortise –
Typically, I’ll work with a scrap piece 2’ to 3’ long – this is just an economy of scale consideration.
(1) Table Saw – I rip the scrap to rough width and thickness – for a #10, this is approximately 1” by 1/2”.
(2) Router Table –
Using a straight bit, I position the fence to within 12mm (finished width will be 10mm) of the bit; then feed the work between the fence and bit FROM THE REAR of the table, so that the bit acts as a thickness planer – you need to be pressing the work close to the fence near the bit, to avoid chatter (Mark this as a SAFETY CONSIDERATION). Using my Incra fence (Kreg or another top fence with micro-adjust will work fine), I plane-down the work to specification. Normally, three passes will be necessary. One key is to take fine shavings from the work.
(3) Once the work is to the desired thickness, use a similar procedure to fine-tune the width – for a #10 domino, normal width is about 25mm (from memory, so you need to check this).
(4) Use a round-over bit to cut the four shoulders – it’s important to reference from the fence, not the router bit bearing, as cutting the round-over eliminates a reliable reference for the bearing.
(5) Switch to a V-bit, lower the cutter to where it will make a heavy scratch on the piece; then run the faces and edges of the piece across the bit – this provides both glue troughs and an enhanced binding surface for the glue. At this point, I’ll push a razor knife edge in the troughs, to clean-out any wood fuzz left by the V-bit.
(6) During project assembly, I use a Bandsaw to cut to required length.
(7) If necessary, relieve the leading edges with 150-grit sandpaper; also, during dry assembly, the sandpaper can be used to knock-down any slight overage (thickness, width) from the machining process.
This sounds much more complicated than it is; in about an hour, I can make 10’ of dominos.
For commercial shops, it’s a question of whether the time is better spent on higher-value tasks (just about everything would qualify); and for the serious hobbyist, whether it’s simply expedient to buy the Tenons from Festool. For me, I enjoy making things, and one of them happens to be Dominos, when I need them.
YouTube has excellent videos on this – HalfInchShy (Paul Marcel) is a master at this.
For those interested in making your own tenons, this is one process – I’m sure there are many, many more.