Monday, April 16, 2012

Oversized Mortises with the Festool Domino XL Domizilla

The Domino XL DF-700 has thicker and longer tenons than the original Domino DF-500.  When you're building larger structures, these can be used alone or in an array of mortises to create strong joints.  While an array of Dominos can provide a lot of glue surface and twist resistance all while being easy to layout and plunge, sometimes you'd be even better served using much wider tenons.

Wider tenons are even faster to layout and plunge than an array and are easy to drawbore or peg for even more mechanical strength and simplified glue-ups.

The largest tenons you can make and directly use with the Domino are 14mm thick, 140mm long, and 68mm wide (for us 'mericans, that's a little over 5 1/2" long by a little less than 2 3/4" wide).  These things look like PopTarts more than Dominos!

In this video, I'll show you the simple procedure that uses the Domino's pin fence to create three oversized mortise widths quickly and easily.  If you've watched my procedure for oversized mortises with the original Domino DF-500, it was a little awkward and relied a lot on lining up the cursor for each plunge.  It works and I've used it many times, but the procedure is all mechanical with the Domizilla and therefore very fast!

The one caveat is that your centered pencil line is not in the center of these oversized mortises.  If you locate the first plunge of the mortise using other means (say, the cross stops or fence pins) and mirror the plunges (i.e., on one board start with the right pins, on the other use the left pins), everything will line up perfectly.  If you really want to center on a pencil line (and I do actually), you need to modify your Domino's cursor to add hairlines at 3, 4, and 6mm from the centerline.  This is really easy to do and I show you the procedure at the end of the video for those who want to stick it out.

The cursor is a replacement part so if you are concerned that you may not want to mark up your cursor or that you'll botch it up, the replacement part number is #701458 and can be directly ordered from Festool USA for $3.21.  I may start bugging people at Festool to modify their cursors to include all the lines from 2mm out as this procedure could greatly benefit people building fences, gates, doors, out-buildings, and monster conference tables.

If you do add the additional hairlines, you'll need to recalibrate the cursor to your Domino.  The procedure is really easy; that link is for a video showing it on the DF-500 though it is identical for the Domizilla (in fact, the part number of the cursor is the same for both :)

The following table shows you the widths of the mortises for each of the 4 bits sizes for all 4 mortise widths (the exact width as you'd normally use plus the three oversized mortises this procedure produces):

Bit SizeSingle PlungeTwo PlungeThree PlungeFour Plunge
8mm ∅21.5mm36.5mm53.5mm66.5mm
10mm ∅23.5mm37.5mm54.5mm67.5mm
12mm ∅25.5mm38.5mm55.5mm68.5mm
14mm ∅27.5mm39.5mm56.5mm69.5mm

Here are the offsets for centering the mortise on the pencil line. These assume the pins used in the video; that is, left-inside, right-middle, left-outside; if you mirror the pins, flip the left/right designator in the table:

Two PlungeThree PlungeFour Plunge
6mm to right3mm to left4mm to right

"6mm to right" means put the pencil line on the 6mm line to the right of the center line.

Note that thought the bit size increases by 2mm for each row, the widths for a type of mortise only increase by 1mm.

For disclosure, I received the Domino XL early as part of the Test Drive program, which requires testers to return the full kit on June 1, 2012 or allows the testers to purchase it at a small discount.


  • Anonymous said...

    Hello Paul, I watched your video a few times and then went and cut some myself. As I see your review again I realize that all of your cuts start from a reference line and not a reference edge like one use for a table leg to apron joint. I want to achieve a M&T joint in the 65 to 75 mm wide range and be able to reference off the leg and apron top edge, any suggestions? Jacko9 (from the FOG)

  • Paul-Marcel St-Onge said...

    Hi, Jacko,

    The method I showed here only works with a reference line. If you want to use an edge, you could just pick one of the pins on the fence to register on the edge of the apron/leg for the first plunge then switch to the inside pin on the fence (closest to bit) and register that inside the first mortise to widen it like was done in the video. The size will come out different than what I have on the charts so you'll want to try it out on scrap to determine the "mortising pattern" and resulting width.