The support brace is a large open triangle that connects the cart’s base and rear panel. The top of the brace also contacts the underside of the top cap, but the connection there is cosmetic.

For this part of the project, I didn’t use my SketchUp drawings. Instead, I clamped the base (un-skirted at this point) to the rear panel, making sure the two were perpendicular. Then I clamped the oversized (lengthwise) stock that would become the triangle’s front (hypotenuse) side in place.

I used my handy protractor tool to capture the tilt angle.

I measured the angle with my equally handy digital angle gauge.

I set my table’s saw’s blade to match, using the protractor as verification.

Then I cut the bottom of the brace’s front side and the front of its bottom side. I couldn’t use my crosscut sled, because I didn’t have a 12.9-degree insert and wasn’t about to make one for two cuts. I used a miter gauge with a scrap as a fence and tear-out reducer.

After cutting the brace’s rear and base sides to length, I marked the angle of the long taper at the top of the rear side.

I didn’t care what that angle was. I just used the mark to position the rear side on my MatchFit sled, which I use to cut tapers. It’s hard for me to see pencil marks on walnut, I used tape to mark the cut line.

Another test fit confirmed that everything was okay. The brace’s front side was slightly long, but that was fine. I’d just trim it after glue-up.

For the glue-up, I used a normal dowel joint for the bottom/rear side joint. For the angled joints, I just held the joints together with my hands until the glue set.

After the glue tried, I trimmed the top of the triangle and added two support dowels to the upper joint and one angled dowel to the bottom joint.

I was finally ready to apply the finish to the parts and assemble the rack.