Routing Tenons

That's all you need to get the job done. With the bit installed in the router and the guide at hand, you're ready to go.

IN THE BALLPARK. You'll start by making a preliminary adjustment of the bit height and fence position.

Then each adjustment is refined with test cuts to produce a dead-on accurate tenon.

A combination square will help you with both adjustments. The bit height is set a little low and the fence is placed a tad close. 1 never try to hit these settings on my first attempt. So be conservative. The idea is to leave some room to sneak up on the final settings.

ZERO IN. Once the initial settings are complete, the next step is to zero in on the final bit height with test cuts, as shown in Figures 1 and 2. Using the guide, make a cut across the tip of both faces of the workpiece. Be sure to press down firmly as you make the cuts. As a rule, I always make a second "insurance pass" on each side once the bulk of the waste has been removed by the initial pass.

Check the fit of the "stub" to the mortise and then tweak the bit height accordingly. Since you're removing material from both sides of the tenon, the height adjustment is doubled. So I always make very small adjustments.

WORK BACK. Once the bit height is fixed and the thickness of the tenon is established, you can start removing the waste back toward the shoulder line. The best way to get the job done is with multiple, light cuts. Nibble away the waste on one cheek until the end of the tenon contacts the fence. Then flip the workpiece over and repeat the process on the opposite cheek.

Keep the workpiece flat on the table and maintain steady downward pressure as you make the cuts. The workpiece should be held firmly against the guide to avoid chipout. This is how you'll get perfectly smooth tenon cheeks.

ADJUST THE FENCE. I like to cut all my tenons to rough length at this point, and then fine-tune the fence setting. This guarantees that the final shoulder cut on all the pieces will be very light and easy.

My initial fence adjustment usually leaves me only about Vi6M or less of waste to remove at the shoulder. And as with the bit height, to hit the final shoulder line, you want to make very fine adjustments of the fence between cuts.

STEADY FEED. It's tempting to slow the feed to avoid the possibility of chipout at the trailing edge. But a slow feed rate can lead to burning at the shoulder. Keep the work-piece moving steadily and trust the backup fence to control chipout.

It's a good practice to make two passes at the final shoulder line — one to remove the remaining waste and a second to be certain the shoulders on both faces of the tenon are cut to full depth.

SHORT SHOULDERS. For a tenon with four shoulders (edge shoulders), you can follow the same procedure. As when routing the cheeks,

Fence set close '

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