ROUTER MORTICING JIG
My router morticing jig is a fixtured acrylic panel. The work is toggled to the fence and excavated through a 3" x 6" window in the panel. A plunge router with a double edge guide is required. The adjustable stops on the panel limit the north/south travel of the router and therefore define the mortice length. The width (east/west dimension) of the mortice is determined by the cutter diameter and edge guide settings. You can rout a one diameter (wide) mortice or widths up to 2-7/8" with the same cutter. The maximum excavation without moving the work is 2-7/8" x 6" long. The jig uses no bearings or collar guides; it is not a templet morticing jig. With this jig you can tune the mortice width to match your tenon thickness.
Its Spartan design has many benefits. For example, the 7 pound jig can be clamped to the bench with one clamp, ready for work, in seconds. It can be stored on a rafter just as quickly. Whilst the jig is fixed to the bench, the work is clamped to the jig. If the sample is large, the jig can be clamped to it. In either case, two handy integral 500 pound DeStaCo clamps hold the work with one pull. The clamps and spacers (accessories) will accommodate stock to more than 3" thick or wide.
The panel is 12mm transparent acrylic. The fence, (fastened in 6 places with 1/4-20 FH caps screws and flange nuts), has been strategically located to render the panel particularly resistant to deflection in any direction. You will play hell bending this package. Moreover, the stuff wears very well, requires no maintenance, and is dimensionally stable. You can see through it to facilitate setup. It is just the right size for its function and there is always more than enough surface for any plunge router. There is nothing in the way for the router to slam in to. The chip is trapped in the mortice well and is easily collectible. A down right pleasure to use and very accurate too. I machine the panel to + or - .0015" in parallelism, a requirement for the precision location of your mortice.
A round subbase (accessory available) is recommended for best results. The straight section of truncated castings and subbases (squared off like the DW 621/625 & Bosch 1613's) may not be at right angles to the edge guide rods. In that event, mortices greater than 1 cutter diameter may not have square ends. ( Note: a 5-3/4" diameter subbase such as the plate on the PC 690/693 plunger will not dip into the window.)
The W.Oak/Aluminum end stops are precision machined. The 12 point lock levers that clamp them are studded and threaded into the acrylic. Adjustment is instant. They slide parallel for more than 4". Their combined travel (8"+) is farther than the window is long. The stops are handed and they are square to .001"/length. They can be used for close layout and metrology when not in the morticing function.
There are 3 things that make this morticer work. They are critical but subtle. The panel is precisely milled to parallel; without that the edge guides will jam as you walk the router down the jig. Moreover, a panel out of parallel will render a tapered mortice. The second criticality is the edge guides themselves, 2 required. The 2 guides trap the router on the platform and restrict the pathway of the router to only parallel cuts. This design feature substantially shortens the user learning curve, facilitates handling the router, and adds a generous measure of safety. The router bit can't crash into the access window and no matter how you steer the thing you wind up with square/rectangular, parallel and straight walled mortices. Simple edge guides are available (from me). A pair of your OEM edge guides will also work, provided you can get at least 12"-14" of space between them. You could also make a pair of simple blocks just like mine and save some money.
The third essential is the toggles (2 supplied) and clamp pad/spacers. The spacers increase the distance under the toggle plungers. The jig, as supplied, will accommodate stock from zero to 1.5" thick; each spacer (an accessory) increases that x 15/32". The jig has essentially no stock width restrictions but the practical limit to thickness is about 4". Stock to 3.2" can be morticed on its edge or face with the toggle clamps & spacers in play. Wider/thicker stock can be morticed but it may have to be C-clamped to the jig. Again, getting more room under the clamp plunger requires spacers. Each added spacer requires a longer screw. The spacer kit consists of two 12mm (~15/32") thick acrylic spacers and 8 Allen head cap screws. Use one pair or up to 4.
To use the jig, first locate the mortice on the work; roughly pencil in its location. Stock should be sized so both clamps are in play. Set the toggles and clamp the work in the jig so your mortice map is anywhere in the panel window. Set the edge guides for zero slop (for single cutter width mortices) and lock them. Now loosen the guide bars on the router and slide the router to your cut line. Lock the rods. Slide the router so the cutter is at the north end of the mortice. Slide the north stop to the subbase and lock, ditto to the south end. Rout to depth, plunging at about 3/16"/pass. Measure and adjust (after the first pass) as necessary. Note that once the edge guide & stops are set, the mortices made at these setting are the same independent of sample size! As such, you can test and calibrate on any ol' piece of scrap and the mortice width & length are insensitive to minor or major errors in work piece section!
Email firstname.lastname@example.org for ordering instructions or questions.
Panel: 12MM cast Acrylic
Fence: 1.12" W. Oak, fully machined with 8 tee-nuts for toggles.
Toggles: DeStaCo U225 500# cap. 250# nominal load.
Weight (fully fixtured) ~ 7.0 pounds
Capacity: Mortices from 0 x 0 - 2-7/8" x 6" x practical length of cutter.
Stock Capacity: Thickness to ~3+" with toggles in play. Length: No length limitation.
Width: Arbitrary. Will mortice within 1/16" of one edge of any width stock or anywhere on stock up to 3" x 3" in section and 1" from any end. For reference, you can mortice a 2" wide centered mortice in 3.5" square stock. Inquire as necessary.
(For more on morticing see the Morticing with a Router link)
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Last modified: Mon Oct 6 07:21:07 PDT 2014