A Tapering Jig for the Table Saw - Part I

The Shaker Hanging Shelf project will involve two tapered pieces, so I need to construct a tapering jig for my table saw before proceeding. The design I will be using is quite basic, employing the saw's miter gauge slot for guidance and simple hold-downs running in aluminum T-track to secure the work to the jig at the desired angle. The dimensions of the jig are 12" X 36", though it could easily be scaled up or down as needed.

Ripping With the Guard

I begin by ripping a piece of 3/4" plywood to width to form the base of the jig. Note that I am using the blade guard/splitter on the saw here rather than the usual riving knife. Because this is a rip cut, I can rely on the fence for guidance and so have no need to see the line of cut clearly. The anti-kickback pawls also add a degree of protection to the process. The guard turns out to be very convenient and makes a noticeable improvement in dust collection.

Planing the Strip

I am using a scrap of maple to make the strip that will ride in the miter gauge slot. I use the planer to trim the strip to the precise width and thickness required.

Measuring

Next, I need to make a dado in the underside of the jig to accommodate the strip that will ride in the miter gauge slot. I will be using the router table for this, but first I need to establish the exact distance between the slot and the saw blade. I do this using a steel rule and the maple strip I just prepared. The distance is exactly 4". The photo at right also shows the close fit between the maple strip and the miter slot in the saw table.

More Measuring

The Dado

I have installed a 3/4" diameter straight bit in the router table. I set the distance between the bit and the router table fence at 4 1/8" to allow me to trim the base of the jig to fit flush with the saw blade, as I will show later. Note that it makes no difference that the fence is not square to the router table, as the dado will still be parallel to the edge. I use a small machinist's square for the measurement, taking care to rotate the router but so its high point is directly opposite the fence. I use a brass gauge bar to set the depth of cut to 3/16". I also make a test cut on a piece of scrap before dadoing the actual base of the tapering jig. The dado turns out to be a perfect fit for the maple guide strip.

Trimming the Guide Strip

Trimming to Final Width

With the guide strip temporarily installed in the dado, I can do some final trimming. I first trim the maple strip to length using the crosscut sled, then rip the jig to its final width. Note that the maple strip runs in the saw's miter gauge slot to guide the cut, so the rip fence is not needed. The next step will be to cut three dados in the top of the jig to accommodate the aluminum T-tracks. I will show how that is done in my next posting.

More to come soon...