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For so many years I have looked at the Porter Cable Omnijig and "saluted" this
"battleship" of dovetail jigs. I always thought it was the production type of
device for doing 1/2-blind dovetails on kitchen drawers. It is that, but what I didn't
know is that it can also do through dovetails and even with variable spacing. So,
does it belong in this Through Dovetail Jig Shootout? A resounding -"yes."
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Beth
starts to learn the Omnijig by removing the 1/2-blind dovetail template that comes with
the unit. It is easy to see that all the templates are extremely well machined and a full
1/2" thick aluminum.
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The
operating instructions are well written and cover procedures for cutting all the different
types of dovetails.
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There is
a large clamping lever for both the top and front board clamps. Here, Beth is making
a fine adjustment to the inside nut to allow for slight variations in board thicknesses.
By pushing in on the hand lever, she can easily adjust the nut from underneath the jig.
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It is
important to use a piece of stock that is the thickness of the piece you will be
dovetailing PLUS 1/4". I am using 1/4" ply here. It is on top for the picture
but in use, I will place it under the stock. This will be used to set the template finger
height. The extra quart inch is to keep you from running the router into the aluminum top
— not a good thing.
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Beth has set the guide fingers for the through dovetails in place and is adjusting the
height using the board with the 1/4" extra. It is positioned at the far left end.
Once she sets that side, she will move it to this end (lower arrow) and clamp the finger
height at this end.
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The
illustration shows the bits for 3/4" and 1/2" stock. We are going to be working
3/4" stock so we select the 3/4" bit that is specified. This is important. I had
several 3/4" dovetail bits available, but not one with 14o angle.
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A quick trip to my
local Woodcraft Store solved that problem. They stock a complete selection of CMT bits.
Next time I will read what's required before hand — hopefully.
It also specifies the exact collar to use — 5/8" in this
case. There is minimal clearance between the 1/2" shaft and the brass collar. By
rotating the shaft, we can check to see that the bit is centered. If it isn't, there
is just enough play in the mounting of the base plate to center the collar.
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In
the other router, Beth installs a 5/16" straight bit — also with a 5/8"
collar. Don't try to use a different size straight bit or a different collar — the
template fingers are designed with these specific bits and collars in mind.
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This
illustration at the right shows the knobs and spacers that hold the dovetail template
fingers in place. There is a thin black washer and a long spacer — the latter about
3/4" long. For preparing the template for the tail cuts, the thin and thick spacers
are placed behind the dovetail brackets.
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The arrow shows the larger spacer is behind the bracket. With those set properly, Beth can
see that the groove of the finger is covering the wood to be cut. This way, the collar
will guide the cut straight in and back — making a straight dovetail slot.
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