Anyone know a good tutorial for mortising on a router table?

[wood_newbie]

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.

[Andy]

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.

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

[JGS]

[B a r r y]

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. 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

[Frank Ketchum]

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.

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

[Frank Ketchum]

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