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Rockler Router Table Box Joint Jig
Modern simplicity for an old joint
Text, photos and Video by Tom Hintz
Posted – 2-3-2013
The only word of caution with the Rockler Router Table Box Joint Jig is that the near edge of your table's miter track (3/4”-wide) must be between 4-1/2" and 6-1/4" from the center of the bit for this jig to fit. The good news is that the vast majority of router tables and tabletops fit this dimension so for most this is not an issue.
Box joints have been around as long as woodworking itself. The problem is that well-fitting box joints have been difficult to make the whole time. Tiny errors in homemade jigs resulted in joints that were frustratingly tight or loose. Some box joint jig designs over the years had a strong Rube Goldberg look with usage instructions equally complex and confusing. The Rockler Router Table Box Joint Jig removes the mystery from making strong, good-looking and repeatable box joints.
The Rockler Router Table Box Joint Jig centers on a fixed 10-3/4" x 12-3/8" x 1/2" base made from MDF with a low-friction melamine coating on the surface. Tough expanding steel miter slot followers lock the base in place. Rockler includes their comfortable multi-point knobs for tightening the miter followers in the slot.
The base has slots machined into it that accept the well thought out sliding ABS plastic fence/sled that comes complete with pre-drilled holes for a scrap backer that helps prevent tearout as the bit exits the wood. The fence slides in two grooves but has limiters built into the “feet” that prevent moving the stock outside the usable range.
A center groove in the sled accepts one of the three indexing keys that match the prescribed bit diameters. The Rockler Router Table Box Joint Jig kit includes ¼”, 3/8” and ½”-keys to give you a wide range of box joint sizes for your projects. The Rockler Router Table Box Joint Jig is designed to work with wood up to ¾”-thick.
You do have to supply a straight bit to match the size key rail you want to use. Rockler recommends an upcut spiral as that gives the cleanest cut in this application. Aside from the bit and material for sacrificial fence face, everything else is included in the Rockler Router Table Box Joint Jig kit.
Sizing Work Pieces
Because the Rockler Router Table Box Joint Jig is open-ended you can make joints as long as you like. However to get a good looking joint we have to pay attention to the width of the stock and how that works out with the size of the joint being cut. To get full pins on both ends of the joint the width has to be divisible by the diameter of the bit being used. For instance, if we are using a ½”-diameter bit a stock width of 4” wide or 4 ½”-wide will work fine but 4 ¼” will leave you short on the final pin. If you hate math as much as I do, there is a better answer.
Once you get the Rockler Router Table Box Joint Jig set up with the bit you want to use, find a piece of scrap that is longer than the widest joint you can imagine making. Cut finger joints over the whole length on the Rockler Router Table Box Joint Jig to make a full-scale gauge. Then when you are planning the width of a project piece you can simply measure the gauge to see exactly what width you can use. Using this “gauge” you can pick a stock width that gives you symmetrical joints – a full pin on the top and bottom or a non-symmetrical – a full pin on top and a full pin on the bottom of the mating piece.
In the Shop
Installing the Rockler Router Table Box Joint Jig really is simple. Assemble the miter slot locks in the base. Install the bit that you will be using and then set the Rockler Router Table Box Joint Jig over the bit and put the miter locks in place. Follow the instructions for setting the key to bit distance. Take your time with this setting as it is very important. Once satisfied turn the knobs down to lock the Rockler Router Table Box Joint Jig in place.
Make a Sacrificial Fence Face
If you are going to use a sacrificial fence face (you should) temporarily remove the aluminum key from the base. Set the sacrificial wood against the fence in position and mark where the key will pass through. With the bit exposed a little more than the height of the key route that material away to make an opening for the key. I used a ½”my rasp to enlarge this opening slightly so there would be no drag on the key. Reinstall the key in to the base, set the sacrificial face over the key and screw it in place using the provided holes in the fence. The first pass you make with the bit at the height for your first joint will cut the opening in the sacrificial fence.
Actually cutting the joints on the Rockler Router Table Box Joint Jig is very straightforward and covered well in the illustrated instructions. I followed those instructions to cut the joint you see in the video and it came out great. If you are new to the box joint I would suggest making a few joints in scrap wood to build a little familiarity. The consistency of the Rockler Router Table Box Joint Jig really does make this an easy joint to make.
I tried tweaking the distance between the key and the bit and it does impact the fit of the joint. Reducing this distance loosens the fit increasing the distance tightens the joint. In either case very small adjustments are needed. Once you lock the base in place you can cut box joints as long as you want with no change. Watch the video below to see how my first set of box joints came out on this jig!
The Rockler Router Table Box Joint Jig is thoughtfully designed and nicely made to help the average woodworker produce good-fitting box joints in a huge array of projects. Joinery is always a focal point of our box projects and the contrast produced by a cleanly cut box joint makes it look all the better.
With a street price of just $79.99 (2-1-2013) the Rockler Router Table Box Joint Jig is a good value that can make your woodworking more fun and better looking for a very long time. Another thing I like about this jig is that despite being capable of making very long joints, it stores easily.
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