Router Housing Jigs:
We show details of the essential housing jig that you will need in your collection.
You can use a router with a fence for lengthwise routing operations, but working perpendicular to that requires either a router T-square, which gives guidance along one side or the extra control possible with a slotted housing jig. This simple device confers control when routing making a lot more things possible and more accurately than without it. For this you need a guidebush big enough to accommodate the right size of cutter. Not only can you make housings. It is a good way to trim the ends of boards square. The jig can be made as long or as short as you desire.
You can use a straight cutter for plain housings. Diameters can vary from small to reasonably large but the guidebush will dictate how large, usually no more than 19mm diameter. Dovetail cutters are used to create ‘locked in’ joints.
It is important to get the batten square
A housing jig needs to be exactly at 90° for accurate cuts or the components may not go together very well. Use an accurate square to check before and after glueup.
The slot must be exactly parallel
The slot needs to be a good sliding fit from end to end. Any tightness will make using the jig difficult and any parts loose will result in sloppy inaccurate machining. A tablesaw is a good way to create reliable parallel outer cuts for the slot. Make sure the housing jig is clamped to the workpiece as vibration and movement of the router will otherwise displace it and ruin your efforts.
A narrow slot being cut before the dovetail cutter
A housing jig can double as a board end trimmer. It can make good square cuts instead of needing to use a compound mitre saw. It also eliminates breakout using a router except at the very end of the cut if it isn’t pressed against sacrificial board. When you’re making dovetail housings do the slot first. The stess on a dovetail cutter is reduced by using a small diameter straight cutter to remove some of the waste. When you do use the dovetail cutter, do not release the plunge or the cutter will ruin your work. Instead pull the router back to you, which will clear the chippings, then switch off.
The matching dovetail tenon using a high fence for support
The other part of the joint, the dovetail, is created on a router table taking cuts either side of the board and checking the fit. It needs to be a snug fit, but the board with the housings must be dead flat or it will be hard to tap the joints together. For a discreet appearance the housing can be ‘stopped’ at the front of the cabinet or shelves. The housing jig needs to have a stop at the correct place so the router cannot machine right through the front edge.
A stopped housing showing the tenon end rounded
For stopped housings, a component with a plain tenon end has a step, and a dovetail has a neatly rounded over dovetail end. Finally, make sure you do test cuts to check the joints will all fit well as there are usually a number of housing joints together in a piece of furniture.