I thought it was a pretty good idea but you know how things don't pan
out as they appear? Thinking about it, and this was long after I bought
the Domino, I considered that a large percentage of my mortises are in
the end of a narrow piece of wood. If the dowels are too far apart you
can only drill one hole and then you give up the strength of two dowels
which would also prevent the joint from rotating, like it would with
only one dowel. Alternatively you could drill one hole and simply move
the tool over and drill another hole closer. BUT that presents a fit
problem, you must drill the mating holes exactly the same distance apart
on the mating side of the joint.
And on top of that even if you use both bits to drill pairs of holes,
alignment of mating holes is going to become an issue with the next set
of holes and each after that. Aligning to a pencil mark is not going to
be accurate enough with precise fitting dowels. This is OK with a plate
joiner as the biscuit can slip back and forth a slight bit.
The Domino has a solution which I use on every one of my mating
mortises. I cut one side as an exact fit mortice to fit the domino
tenon and the opposite side mortice is cut slightly elongated, wiggle
room. The bit simply swings slightly wider left and right when cutting
on that setting. IIRC the smallest setting for an elongated mortice is
about 3/16" wider than an exact fit. FWIW I never mate exact fit
mortises together. The Domino has an indexing system to insure exact
placement however the Festool reps explained that this is accurate as
long as the internal adjustment on the side to side movement of the bit
remains dead center. There is an eccentric adjustment, to compensate,
on one of the indexing pins but I never use it.
Knowing that, I decided to not bother with exact fit mortices holes on
both sides. This very reason may be why some Domino owners do not use
their machines as much as I do. I don't expect the tool to always
perform precisely as designed, due to normal wear or what ever, so I get
to use it ever where I want with out alignment problems 10,000+ mortises
later. Is that clear at a all? LOL
>
> Heck, I remember when dowel joints were considered great woodworking
> and a sign of craftsmanship. When I learned to lay up panels, we
> always did a few dowels per joint. I remember doing doweled miter
> joints on rail/stile construction, too. Looks pretty old fashioned,
> now...
>
>
Yeah! I have one of those doweling jigs around here somewhere, I think.
You know the one with a turret and probably sitting beside that one
the self centering one. ;~)
I experienced similar problems with both that I mentioned above.