Another Mortiser Question

[TEF]

Pursuant to getting a new Delta mortiser (14-651), I am concerned about how one ensures that he/she cuts a slot in, say, the centerline of a piece (and not slightly left or right of that spot). Can one assume that the point of the auger bit, if placed on the centerline of the piece will result in a centered mortise or does one measure from the outside flat of the chisel housing to the edge of the piece to determine distance to the center of the piece? Because of the clearance in the center of the mortising bit, it's not clear if that the auger tracks exactly the same as the chisel part. Is there a jig, template or procedure that could be followed that eliminates the error from this measuring operation? It would be nice to benefit for the skills that are present in this newsgroup without spoiling lots of nice wood to learn the operation of this machine.

Thanks and Regards, TEF

[Swingman]

Note that not all mortises are "centered" between the edges of the workpiece.

Mark the location of the proposed mortises on your workpiece with a pencil or use a mortising gauge. Then use the marks to align the chisel, not the bit.

As you are operating the machine, the left and right limits of the _chisel edge_ are defined by your marks, the front to back, or width of the mortises, by the fence.

Tip: ALWAYS reference the same edges of your workpieces with the fence.

[Leon]

You use the back fence to gauge the distance from the edge. Use a scrap to test and verify your measurement is correct.

[patrick conroy]

I'd have said "and not fore or aft" of the spot. Anyway - you don't typically mark the centerline. I mark the outer boundaries of the mortise. Then you let the chisel points, at the corners, ensure you're on the mark.

Within reason, probably. Meaning nothing a little 120grit or scraper wouldn't fix.

*Always* test things on scrap, milled to precisely the same dimensions...

[Larry Jaques]

On Fri, 12 Nov 2004 08:47:02 -0500, "TEF" calmly ranted:

I bought the Shop Fox mortiser and love it. Be aware that the new Deltas are Chinese-made now. (So say the specs on Amazon for 14-651)

I clamp a scrap piece in there, setthe fence, bore a hole, and check with a pair of dial calipers. If it's off, I adjust with the little screw on the back, bore, and recheck.

But I haven't done a straight mortise yet. They've all been offset with reveal. As long as all of them are even, 0.001" precision isn't an issue.

Alternatively, mark the hole and leave the drill bit out of the mortiser, run the chisel down and adjust for a centered bore. Then insert (and set up) the bit and you're ready to go.

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