I've always done my mortises with a drill press/forstner bit, but
recently decided to try using a plunge router (with an edge guide) and
a spiral upcut bit.

The results were somewhere between disastrous and hilarious. At least
in my untrained hands, there's too much play to keep the upcut bit from
snagging somewhere along the line and destroying the mortise
completely. (Throw in dangerous in the front of this paragraph while
you're at it...)

I'd like to try using the upcut bit on a router table, but somehow
rasing and lowering a piece of hardwood freehand (against a fence) onto
a spinning bit seems like it could be even more
dangerous/disastrous/hilarious.

I've googled with no luck...anyone know of a link that teaches this
technique?

TIA.

I've always done my mortises with a drill press/forstner bit, but recently decided to try using a plunge router (with an edge guide) and a spiral upcut bit. ...anyone know of a link that teaches this technique?

One link is from Highland Hardware's website - download "Tage Frid's
Mortising Jig" from this page - available in a pdf or as a separate
html page. A few more pictures would help in my opinion, but it's
described thoroughly.
http://www.tools-for-woodworking.com...on=Custom&ID=3
Also, I just made a jig that's somewhat similar - simpler but less
adjustable. It might give you ideas depending on your application.
Basically a rectangle of 1/4" hardboard, with a cut-out of about 6 3/8"
x 12 3/8" (depending on the size of your router sub-base and desired
mortise size). Then I took this rectangle and screwed it to a piece of
MDF for the router base to ride on, and since the MDF extends beyond
the hardboard, it is a good clamping surface also. Plunged the router
with 1/4" spiral upcut bit through the MDF, and you get the exact
cut-out shape you'll get on your workpiece. Some centerlines inside
that MDF mortise and on your workpiece help with alignment. Clamp
MDF/hardboard jig to workpiece and plunge away - works well with
shallow mortises of a single size, at least (that's all I've done so
far). This is essentially 4 fixed edge guides on a sub-sub base, if
that makes sense.
I agree that trying to lower a piece onto a spinning bit on the router
table is a bad idea - not sure about hilarious, but it sure has
potential for disasterous or dangerous.
Good luck,
Andy

From your free hand experience I am guessing that you tried to take too
much out at a pass AND quite possibly you were routing in the wrong
direction causing the edge guide "not " to be pulled against the edge of
the piece.
We do the fence thing all the time when we need blind mortises. Cheers, JG

wrote:

I've always done my mortises with a drill press/forstner bit, but
recently decided to try using a plunge router (with an edge guide) and
a spiral upcut bit.

The results were somewhere between disastrous and hilarious. At least
in my untrained hands, there's too much play to keep the upcut bit from
snagging somewhere along the line and destroying the mortise
completely. (Throw in dangerous in the front of this paragraph while
you're at it...)

I'd like to try using the upcut bit on a router table, but somehow
rasing and lowering a piece of hardwood freehand (against a fence) onto
a spinning bit seems like it could be even more
dangerous/disastrous/hilarious.

I've googled with no luck...anyone know of a link that teaches this
technique?

TIA.

wrote:


I'd like to try using the upcut bit on a router table, but somehow
rasing and lowering a piece of hardwood freehand (against a fence) onto
a spinning bit seems like it could be even more
dangerous/disastrous/hilarious.

That's exactly what I do, with stop blocks clamped to the fence(s) to
define either end of the mortise. Tilt the board (end-to-end wise) on
to the bit in the center, so the tile doesn't mess up the ends of the
mortise. A firm grip _IS_ required. G For items too long for stop
blocks, I'll use a block at one end or the other, and a stop mark for
the remaining end.

Try staying shallow for your first practice attempts, as the bit will be
much less likely to grab. With experience, I can do a 3/8" wide x
3/4"-1" deep mortise in one shot, and have good results and no unwanted
adventure.

On the flip side, you could always build one of the many jigs out there
and mortise with a plunge router right side up.

Once you get the hang of it, the table method is fast, plenty safe, and
accurate.

Barry

A few pix on open ended mortices at the
http://www.patwarner.com/cutter_depth.html link.
I would not recommend nor explain blind ended (suicide) morticing for
the router table; that is an edge guide/plunger operation.

wrote:
I would not recommend nor explain blind ended (suicide) morticing for
the router table; that is an edge guide/plunger operation.

Have I been lucky? I've probably made 50 blind mortises on my router
table.

I usually slap a piece of masking tape on the fence above the
workpiece, and mark lines where I will start and stop a mortise. The
lines are positioned such that one end of my workpiece will be at the
start line in the beginning, and the stop line at the end of the
mortise.

I put the far end of the workpiece on the table against the fence, then
tip the other end down onto the spinning bit. This is done such that
the workpiece will be lined up with the start line on my masking tape.
Once the piece is on the bit, I move it slowly to the finish line,
firmly pressing to the table and fense.

When I reach the finish line, I lift the workpiece straight up while
keeping fence-bound pressure on it. The bit is still spinning for my
next piece.

Is this a dangerous way to work?

Thanks,
Mike

I guess I have been lucky too. We followed a similar procedure to yours.
We used to make a lot of billiard ball racks. The shelves were about 2.5"
wide and we needed to groove the centre of the shelf and run it to about 1"
from each end. I guess we could have made a jig to hold the shelf and allow
enough room to allow for the distance from the bit to the edge guide. JG

Mike Reed wrote:

wrote:
I would not recommend nor explain blind ended (suicide) morticing for
the router table; that is an edge guide/plunger operation.

Have I been lucky? I've probably made 50 blind mortises on my router
table.

I usually slap a piece of masking tape on the fence above the
workpiece, and mark lines where I will start and stop a mortise. The
lines are positioned such that one end of my workpiece will be at the
start line in the beginning, and the stop line at the end of the
mortise.

I put the far end of the workpiece on the table against the fence, then
tip the other end down onto the spinning bit. This is done such that
the workpiece will be lined up with the start line on my masking tape.
Once the piece is on the bit, I move it slowly to the finish line,
firmly pressing to the table and fense.

When I reach the finish line, I lift the workpiece straight up while
keeping fence-bound pressure on it. The bit is still spinning for my
next piece.

Is this a dangerous way to work?

Thanks,
Mike

"Is this a dangerous way to work? ": In my view, yes. A timebomb.

wrote in message
ups.com...
I've always done my mortises with a drill press/forstner bit, but
recently decided to try using a plunge router (with an edge guide) and
a spiral upcut bit.

The results were somewhere between disastrous and hilarious. At least
in my untrained hands, there's too much play to keep the upcut bit from
snagging somewhere along the line and destroying the mortise
completely. (Throw in dangerous in the front of this paragraph while
you're at it...)


Do you have the workpiece firmly clamped? Are you only taking 1/4 deep cuts
at a time? Are you holding the router with both hands and keeping adequate
pressure against the guide? If you are doing all of this, plunge cutting
mortices is safe and easy.

I'd like to try using the upcut bit on a router table, but somehow
rasing and lowering a piece of hardwood freehand (against a fence) onto
a spinning bit seems like it could be even more
dangerous/disastrous/hilarious.


Mostly dangerous. It's only funny until someone looses a finger.

"Frank Ketchum" wrote in message
link.net...

Do you have the workpiece firmly clamped? Are you only taking 1/4 deep
cuts at a time? Are you holding the router with both hands and keeping
adequate pressure against the guide? If you are doing all of this, plunge
cutting mortices is safe and easy.


Forgot to mention feed direction. One direction is correct, one is very
much incorrect.

What is it that will eventually go wrong?

Quality results, (square, unchattered mortice walls, no burns, etc),
are rare.
You can't safely cut a mortice 1 cutter diameter, the work can
spontaneous self feed at at any moment, if you lose the work it will
break the cutter and kick the work all over the place, depth of cut
changes are profoundly difficult, the chip will clog the cutter
pathway, layout is guesswork, etc etc etc. Don't do it.

http://www.patwarner.com (Routers & Safety)