Saturday, November 12, 2011

Extra-Wide Domino Mortises

The Domino XL DF-700 ("Domizilla" is easier to say...) is out in Europe, on the way here, but doesn't prevent us from making nearly 2 3/8" wide (58mm) mortises with its tiny cousin the DF-500.

In this video, I'll show you how to create your own loose tenon ('Domino') stock from project scrap and plunge repeatable oversized mortises.

Why would you want oversized Domino mortises?  Many joints benefit from a larger mortise; best example is an apron-to-leg joint on a table.  Sure you could plunge 2-3 regular Domino mortises, but this technique gives you another option.

The video references a printable guide I put together to help calculate the size of an extra-wide mortise given a bit size and which offset cursor hair (the lines to either side of the center cursor) you use.  Here is a direct link to the PDF you can save and print at home: Printable Extra-Wide Domino Mortise Guide.

While this technique may seem more complicated than it is worth, I've certainly used it many times; using the Domino to plow a larger mortise is so much faster even with glancing at this chart than is pulling out your router, finding the upspiral bit and calibrating the edge guide.  Give it a go on some scrap like I did in the demo and you'll find it pretty easy.


  • JimE said...


    Another valuable lesson. I really look forward to your vids.

    Oh ya, thanks for leaving in the "AHHH S^momentsents. I learn a lot from them too.

    It also proves your real.


  • HalfInchShy said...

    Thanks, Jim! Appreciate the compliment.

    Somebody else remarked that the mistake I made at the end of the video proves the Domino is too fast a tool and prone to making mistakes. Truth be told, the tool I was operating at that moment was the camera... it has the attention so I messed up on the reference side of a 1/2" wide "pencil line". Eh, a shorter table would have been okay anyway :)

  • Alan M said...

    great video as usual paul

    great way to make a wider slot.

    i dont like using those lines as it allows for error.
    you could make a marking gauge (like a dovtail marker but square) to mark the correct spacing of 2 center lines and use the domino the normal way.
    when i use this technique i will make up a set of (business potential there for you, or ron wen) gauges for marking the 2 lines. a piece of aluminium angle cut to the right width and with a center position v groove to allign it with the center of the larger mortice

  • Jim A said...

    Another great video, Paul, and an underused application for the Domino.

    Great to see that you were paying attention during Spinal Tap. Nigel was ahead of his time.


  • RONWEN said...

    A very good idea Paul and a handy pick chart that you made for us. I'll no doubt buy the new "XL" since I'm hooked on Festools however your idea expands the 500 well into the 700 range.

  • Anonymous said...

    I don't see why it is necessary to create your own tenons. Why not just place two (or three) Dominos side-by-side into the larger joint created using your great method. (I would understand if you were creating a deeper joint).


  • HalfInchShy said...

    Hi, Christopher,

    You certainly could place Dominos side-by-side in the slot assuming you used a slot size that would accomodate them. The disadvantage of side-by-side Dominos is the gap where the rounded sides meet in the middle. For 10mm Dominos, that's 10mm or nearly half an inch, which is significant. Too significant? depends on your application.

  • Anonymous said...

    I'm a bit late with this comment..
    It would be great to have extra long 10mm bits to use with domino 500. This way we could use 10x100mm dominos. Firs you should do the normal 10 mm hole, change the bit end extend it deeper. IS there any third party bits available for domino 500?

  • HalfInchShy said...

    The problem with changing the length of a Domino bit is that the width of the mortise changes. The Domino doesn't create a mortise like we normally do with a router: back and forth with progressively deeper plunging. Instead, the Domino does it by sweeping the bit side to side like a window wiper. Without a way to adjust how far the sweeping goes, you'd get wider mortises for longer bits, narrower for shorter. (e.g., the 4mm bit is shorter and it's mortise is much narrower than the standard Domino width).

  • Unknown said...

    Paul, what was the tool that you used to round over the tenon?

  • HalfInchShy said...

    That's a Veritas cornering tool.

    They now also have one under the Lee Valley brand that looks more comfortable: Lee Valley cornering tool.

    Honestly it takes seconds with a rasp as well and they don't need to be super snug either as the gap in that radius will be for glue relief since there are no grooves in the flat faces of the oversized Dominos.

  • Nick said...

    Hi! I know I'm kinda reviving an old thread, but I happen discover it today. I don't know if you still have the DF500 with the metal pins, but wouldn't a nice way to drill oversize mortises be to :
    - plunge a wide mortise where you want your (say) leftmost part to sit
    - register the left metal pin against the left corner of the mortise you just cut
    - plunge another mortise (wide or narrow, depends what you want the final size to be)
    - plunge in the center in the same fashion as your "three plunge" mortises to close the gap ?

    I thought it would work, but anyway, with the new black plastic dogs we can no longer register inside a mortise and they are spaced further apart. And the fence addons for repeated plunges would make for 10+cm wide mortises so...