Mastering Machine Made DovetailsComments (0)
I pride myself on my hand-cut dovetails. Clean, tight, and elegantly spaced, they provide a handsome touch for my most demanding work. However, when I build kitchen cabinets, vanities, or storage units, I turn to my compact, portable, and easy-to-use Porter-Cable dovetail jig. Although this jig can execute finger joints, sliding dovetails, and even through-dovetails (when equipped with suitable templates), I use it exclusively to join drawer parts with half-blind dovetails. (See page 36.) Using the jig is faster and more convenient than hand-cutting dovetails and, for all practical purposes, the joints are just as strong. The disadvantage with this jig is that neither the angle nor the spacing of the tails can be changed, so the resulting joint looks somewhat monotonous. All the same, this limitation is easy to accept, given the practical advantages.
Here, I’ll share some tips on how to use the jig to build a standard drawer with a 3/4"-thick front, 1/2"-thick sides, a 1/2"-thick back, and a 1/4"-thick bottom. Note that I usually dovetail the front to the sides, but use a simple dado joint to connect the sides to the back. Initially cutting the drawer sides a bit long means that if I’m unhappy with the dovetail fit, I can take another shot at the joint before cutting the drawer sides to final length.
Before making sawdust, set yourself up for success
Problems with machine-made dovetails can often be traced back to poor prep work. If you pay attention to the details described here, you’re much more likely to get your drawers right the first time. As for material, I typically use the same species of wood for drawer fronts that predominates in the host project. I usually make drawer sides from clear pine or poplar. For the bottom, hardwood plywood usually serves just fine.
- Size drawers for attractive tail layout (see below).
- Make extra parts for trial setups. Also, let sides run an inch or so long, which allows a retry before cutting sides to final length.
- Plane stock to uniform thickness.
- Carefully square the parts.
- Mark the inside faces of parts for orientation.
- Mount the jig on a board for clamping or screwing to your workbench.
- Use a sharp router bit.
Size drawers for attractive joints
A properly made dovetail joint should terminate at each end with a half-pin, not a half-tail. With a fixed-spacing dovetail jig like mine, this. necessitates designing your drawer heights to suit the jig template. It’s a great help to keep a full-length sample corner on hand for reference.
For further information on using a half-blind dovetail jig, see "Router Dovetailed Done Right."
Mind your pins and tails. A joint that terminates with a half-tail (particularly at the top of the drawer) looks odd. Whenever possible, size your drawers to start and end with a half-pin. If that’s impossible, locate the half-tails at the bottom.
Mark the inside faces of parts to indicate matching corners and bottom grooves.
Ready, set, rout: work with care and confidence
This ingeniously designed jig cuts the mating pin board and tail board at the same time, using an aluminum template to guide a bushing mounted on your router subbase. Porter-Cable provides everything you need, including the bushing, the template, and a 1/2"-dia. 7° dovetail bit. The tool manual explains setup and use of the jig. Read it carefully and incorporate the tips here for great results. Don’t let the operation rattle you; just firmly and carefully guide the router along the template fingers without applying undue force. Make sure to cut trial joints to fine-tune the jig setup before cutting into your project stock.
Jig setup. To prepare the jig for use, abut the inverted pin board against the tail board underneath one end of the template, with a support board under the other end to keep the template level. The top clamp holds down the pin board and support board, while the front clamp secures the tail board firmly in place against the jig. For symmetrical drawer joinery, half of your drawer joints will be made on the left-hand side of the jig, and half on the right.
Get a grip. For accurate cuts, it’s important that the workpieces don’t slip during the routing operation, so make sure to adjust the clamps for maximum pressure on your stock.
Safe engagement. To prevent template damage, make sure to engage the router bushing fully in its starting template slot before hitting the switch. After completing the cut, let the bit stop completely before retracting it from the template.
Trial cut. Having cut trial boards with your preliminary jig set-up, it’s time to remove the pieces and connect them to check the joint fit.
A fine fit is worth the fuss
Don’t be surprised or frustrated if your first few cuts don’t make the grade. Take your time, and get it right. If the end of the drawer front is offset from the drawer side, adjust the template fore or aft until the parts line up. If the joint is too loose or too tight, adjust the bit projection.
Too tight. If fitting the joint requires forcing it and breaking the tails, raise the bit to loosen the joint the appropriate amount.
Too loose. To fix a sloppy joint fit like this, lower the bit, and then take another trial cut. Remember that tiny adjustments make a big difference.
Just right. A well-fit dovetail joint exhibits no gaps, and requires only light tapping to drive it together. The parts also align nicely at the end of the drawer front.
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