Exact Width Dado Jig

Blame it on imports, blame it on the metric system, blame it on lumber companies trying to squeeze more out of less…blame it on whatever you want, but there’s no denying that plywood and other sheet goods don’t come close to their “nominal” dimensions these days. What’s worse, the actual dimension is highly variable among brands, sheet type and country of origin. That means you can’t just buy undersized router bits and hope they’ll cut a groove that fits. Woodpeckers new Exact Width Dado Jig delivers perfect fitting dadoes by avoiding measuring altogether…it uses the actual material you’re fitting into the dado as the gauge to set up the cut.

After a quick trim pass to match your router to the jig, all you have to do is fit your stock snugly between the edge guides and you’re ready to make a perfect fitting dado. Your router guide bushing follows the jig’s rails while the router bit cuts a dado perfectly matching the thickness of your stock. It’s that simple. No measuring, no test cuts, no scrap. If you’ve ever used a track saw and guide rail, this jig works similarly…except double…the edge guides are on the exact cutting lines of both sides of the dado.

If your project calls for blind joinery, built-in stops at each end of the jig limit the travel of your router. All you need to know is the diameter of your router base and how far back from the edge you want to stop the cut. The easy-to-read engraved scale makes it fast and simple to set up.

The precision scale used to set your stops serves double-duty. It slides out of its track so you can use it to set your router bit. The scale compensates for the thickness of the jig…no math involved, just set the depth of cut you want.   

All four corners have wide, stainless steel clamping pads to secure the jig to your work. One corner is fixed at 90° to keep your dado perpendicular to your workpiece…no separate square needed for setup. The guide rails are machined from the same solid phenolic used in our top-of-the-line router tables. The sacrificial edge guides will last for multiple dado projects and only need to be replaced if you change to a different combination router bit and guide bushing. You can rout dadoes as narrow as 3/8" and up to 1-1/2" wide. 

In its original OneTIME Tool release, the Exact Width Dado Jig had a maximum capacity of 24-1/2". That size is still available, but now we’ve added the 32-1/2” model.  If your case work routinely calls for vertical grooves in cabinet sides (for adjustable shelf track in upper cabinets, for instance) or you do larger furniture projects, the 32-1/2" model is just the ticket. Both sizes can close down to cut a dado just 5” long.

There are replaceable, zero clearance blocks at each end of the jig to eliminate splintering and tear-out. These blocks are simple to make yourself, or you can order replacements from us. The jig comes with a precision-machined 1/2" diameter Porter-Cable style template guide bushing and a matching spacer (you’ll need it to make that first trim cut). If your router doesn’t use the PC style guide bushing, any 1/2" guide bushing and 3/8” router bit combination will work. All hardware, the adjustable stops, the offset scale and offset indicators are made from stainless steel. In short, this is a bulletproof, lifetime tool that will keep your dadoes fitting perfectly for years, no matter what the plywood manufacturers do in the future.

The Exact Width Dado Jig now joins Woodpeckers line of always available permanent products. Like all Woodpeckers tools, they are precisely machined and carefully inspected in their Strongsville, Ohio manufacturing facility (just south of Cleveland).