Mortising Jig - Max Version

TPro Mortising Jig:

I decided to build a custom mortising jig recently. I really like loose tenon joinery as its strong and to me easier than traditional mortise and tenons. As always, money for WW (at my place) is in short supply. So, buying a Festool Domino is not in my foreseeable future. More importantly, I’m a gadgeteer that really enjoys designing and building jigs & tools.
Over the past few years I’ve made many of the diy mortising jigs in the books and on the internet and haven’t been totally pleased with the results. So, I decided to build my own version. I may have overdone it a bit this time but it was fun and I think I’m set for now.

PICTURES:
1. Front view of jig with a piece of 1×4 pine installed and ready to mortise.
2. Back side showing router edge guide and top plate that router base slides on.
3. Side view – see hardwood block attached to edge guide that runs in a slot also incra T-Track Plus and Stop blocks.
4. Work Piece Hold Down Fixture – removed from jig
5. Fixed plate – attaches to base of jig by 2 holes at top that have 5/16 brass threaded inserts installed. Back side of jig has holes for bolts to attach this plate. Dados indexes the slider plate (next photo).
6. Slider plate with hardboard guide that runs in the grooved of the fixed plate. Note: this plate does not need the dado that runs 90 degrees from the hardboard guide.

FEATURES:
Uses a plunge router loaded with spiral upcut bits. A guide rail slides in a groove on the backside of the jig. I use PC 690 with a plunge base, PC Edge Guide, and 1/4”, 3/8” and 1/2” carbide upcut router bits.
With this jig the full length of the bit can be used for deeper mortising capability than some other jigs allow. INCRA T-Trak plus permits the lateral stops to be precisely indexed for perfect length mortises.
The larger size of this jig makes for easy mortising setup for small and large work pieces alike. On hindsight a smaller version might be just fine.
Large vertical base plate and vertical slider plate (18” square each) remove for easier storage.
Jig top plate is made from a scrap of Corian solid surface material. It’s dimensionally stable and the router base plate slides very easily on it (and it looks cool to me). A piece of 3/4” plywood would work just as well as a top surface.
The Jig’s base clamping “wings” extend 2 1/2” on each end to permit easy clamping to a workbench. Note: a bench vice and dogs could be used to secure the jig as well.
This Jig is not overly complex to build with normal shop tools (although there are plans for far easier jigs you can build out there).

BENEFITS:
The jig base is easily clamped to a work bench.
Repeatable cuts in successive work pieces is a breeze following a few procedural guidelines.
Lateral stops (to limit router travel side to side) very easily set.
A hold down clamp’s is adjusted to permit assorted work piece thicknesses to be easily clamped tight near their centers. It is mounted on 3/4” thick piece of plywood and slides up (or down) to adjust where the clamping pressure is put on the work piece.
Ability to cut mortises on the edge of a board as well as on the ends.
Capability to easily cut mortises on a mitered 45 end (to be developed later).
No additional base plate is needed to be attached to the router (only an edge guide).
Can be set on a shelf or hung up when not being used (both face plates remove for storage).
Amazingly fast, accurate, clean, and repeatable mortises.

Cut procedures to follow; but my “hunt and peck” keyboard style leaves me weary for now.
No plans drawn up yet, but you would need to adjust for your router base and edge guide anyway.
Hope you like it.