# Incra Ultra How-To (Box Joints + Other Stuff)



## Nickbee (Nov 1, 2007)

This is not a review of the Incra Ultra. It’s awesome, there’s nothing to review. If you like precision and repeatability go get one. To call it a jig in an injustice. Sure it comes with templates that make dovetails and other decorative joints easy, but it’s much more versatile than that as you’ll see in this post. 

For this post I’ll take you step by step in making a decorative box with simple box joints, a rabbeted box top and “router whittled” handle that attaches with a loose tenon. This is also my 1st attempt at bottom inserted in a stopped dado. I’ll also go over some “hard learned lessons” from using this thing over the last few months. Let’s get started.

Here’s the raw material. A ½” x 3.5” x 2’ piece of poplar from Lowes. These pieces are cut VERY precise and if you hunt you can find some good grain patterns. I cut 4 pieces 3.5” long (this is going to be a cube) and mark the inside tops of the box. I’ll keep everything in order so the grain flows from side to side on the final box:










I’m going to make the box joint cuts ½” x ½” to stick with the cube theme. For that I break out a ½“ upcut bit:










To set the bit height I use two pieces of stock. For box cuts you want the height a hair (1/64” - 1/32”) over the stock thickness. You’ll see why later: 










Next I set the initial fence setting. For this I use a piece of brass square stock:










I use the micro adjust feature to make the bit flush with the fence. Each line on the dial represents 1/1000”:










Once that’s set I lock the fence and move the ruler to read -½” on the scale indicator. 










Then I set the fence to 0:










This gives me the location of the 1st cut (½” bit sticking ½” out from the fence face). 










Next I set up the 90 Deg jig that comes with the Incra Ultra package:










HARD LEARNED LESSON #1
Adjust the nylon screws on this jig as tight as possible with still being able to slide the jig. On my 1st box joint attempt these screws were too loose. This resulted in play and very loose fitting joints:










HARD LEARNED LESSON #2
Always test your set up on scrap. When making a joint for the 1st time go all the way through and complete one corner. You’ll practice the speed of feed and make sure everything fits well. Here’s the 1st cut in the test piece:










HARD LEARNED LESSON #3
After making the cut all the way through the material STOP and shut off the router. Wait for the bit to stop spinning then back the piece away. This will prevent the bit from making multiple cutting passes. Even with a tight set up this will introduce some play in your joints. 

Now it’s a matter of moving the fence over in 1” increments and repeating the cut:



















BTW the ultra comes with many templates that allow for easy cutting. The fence setting of each cut are marked with red and blue lines (a and b cuts). But for simple joints I find the ruler is just as easy to use.

When cutting out material at the end of a board it’s best to take a few passes at it:


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## Nickbee (Nov 1, 2007)

And that’s side a done for the test piece. 

For the mating side b I make the 1st cut with the fence setting at ½”:



















Just like before I move the fence 1” at a time and repeat the cuts:



















And here’s the test joint put together. The fit is tight and right. Also you’ll see how the pins stick out by that hair that we over adjusted the bit height by. This is done on purpose so we can sand everything flush later:










HARD LEARNED LEASSON #4
It’s much easier to sand the pins to meet the sides than to sand the sides to meet the pins.

Now it’s time to cut the real thing. Note the backer scrap. This prevents tear out on the work piece. You could cut more than one piece at once but I find things are more accurate this way. Besides, this is fun and I’m not in a rush:










HARD LEARNED LESSON #5
Always index your fence setting from one side of the box (top or bottom). You’ll see how I’m butting the marked side (in this case the top) against the fence. This means that even if all your joints are not centered perfectly they will still line up ok. Just a bit of insurance…

The 1st a cut is done:










Here are all the a cuts lined up. This is where the repeatability of the Incra shines!










HARD LEARDED LESSON #6
Look at your bit / piece after adjusting the fence. And make sure it looks right. There is nothing more frustrating than realizing you are making the wrong cut half way into the cut. But I must say it does make for some very colorful language:










Here are all 4 sides cut:










Now you’ll see I made each piece identical. This is a preference thing. With a trade off. In this configuration each side will appear the same but not systematical. By making the pieces symmetrical all 4 sides will not look the same. In retrospect I think this box would have looked better with symmetrical joints. I think this style lends itself better to more cuts or rectangular fingers. But I approach woodworking like cooking. Even if you screw up folding an omelet it still tastes good! 

Next it’s time to situate a bottom. I typically just cut a rabbet and glue a bottom. For this project I want to try trapping the bottom in a stopped dado for a cleaner look. I want my bottom to be slightly thicker than ¼” so I can take multiple passes with my ¼” straight bit and get a perfect snug fit. To accomplish this I start removing some material using the same ½” straight bit:










You’ll see I’m leaving an 1/8” leg on each side:










After making a few more passes raising the bit a little at a time I’m at .280”:










Next I rip off the legs and cut the bottom to size:










Now I switch my bit over to a ¼” upcut to fashion the stopped dado for the bottom:


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## Nickbee (Nov 1, 2007)

It’s called a stopped dado because the cut is stopped before reaching the end of the joint finger. The incra stop that comes with the ultra works well for this:










After making the initial ¼” dado I move the fence a little at a time and cut again until the fit is snug. The micro adjust knob works great for this: 










Now we are ready to start gluing. Before I do I finish sand the inside of the box with 220 paper and mask the corners to keep squeeze out clean up to a minimum. 










The clamps and squares come out and hold everything in place while the glue (Titebond III) dries.




























While the box is drying I hatch a plan for a lid handle. I picked up some great Poplar 1x2 at Lowes that had some great natural purple staining:










The 1st step to thickness plane the stock to about 3/8” thick. Similar to the bottom I use the ¼” straight bit and take small passes to get the end of the stock to the right thickens:










Because I have 2 feet of stock to hold I don’t need the “legs” while cutting. 

After a few passes I’m perfect at 3/8” thickness:



















Next I mark out the rough shape of the handle so I can figure out where to put the mortise for the loose tenon. 










This is my 1st attempt at a router table mortise (or any mortise for that matter). I forgot where I heard the tip of “rocking” the piece back and forth while making the plunge, but it works beautifully:



















Having the rest of the stock to hold on to helps also. 

Next I take small 1/16” passes off the other side of the handle until the size looks right looks right. 










After cutting off the whittled stock on my table saw I cut some angles on my disc sander:


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## Nickbee (Nov 1, 2007)

I’m careful to keep the mortise centered as I sand away:



















Next I plane some stock (on the router table of course) to ¼” and round over the sides to create the floating tenon:










Who needs a Domino!? Just kidding, I wish I had one!

Now that we have a handle we need a top for it. 1st I cut a square to size and route rabbets so it sits in the box:










Then I route a matching mortise to accept the handle.










Next I switch to a 45 deg chamfer bit:










After taking a few light passes the lid is ready to go. Here’s the box all sanded and ready for finishing.










I keep the finish simple and easy with just a few coats of natural Danish Oil. This plays well with the wood’s grain and the natural purple color of the handle:



















Here’s a shot of the bottom. The dado makes for a clean look:










Overall I’m happy on how the box came out and I got to try a few new things! And I know there are easier ways out there to accomplish these tasks. But being that serious woodworking is a new hobby for me I’m limited to the machines I have available. So as you can see I’m relying heavily on my router set up. But it is fun!


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## cigar364 (Jan 21, 2008)

Got same Ultra only TS version mounted on my Powermatic 2000 w/ forrest Woodworker II thin knerf and if you use those templates you aviod ANY fluxes in indexing those repeat cuts like stackedup mistakes that lead to 1/64 or more off when reaching last cut.


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## aclose (Nov 11, 2007)

nice job NickBee, and thanks for posting tutorial style. i'm looking forward to some warmer weather so i can get out to my garage shop and try some box jointing :smile: i haven't decided whether i'm going to try to make a jig or buy one yet...


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