Circle Arbor

The side gate to our garden was disintegrating. I asked my wife what she wanted to replace it with, and she did some browsing online. She found a lot of great options for gates and arbors but the one she really liked was this one. It did look complicated to make but I had to admit the circular gap created by the arch and the gate looked pretty cool. Luckily, a friend of mine had recently purchased a CNC router, so the curved elements did not pose an insurmountable problem. Having said that, this project is not straightforward and I recommend taking it on only if you are a reasonably experienced woodworker or DIYer.

All lumber should be cedar or pressure-treated. You will need a variety of power tools; I made use of a table saw, miter saw, cordless drill and even a CNC router.

• 4 10' 4×4 posts
• 4 8' 10×2 planks
• 4 8' 4×2 boards
• 5 6' 6×1 tongue-and-groove boards
• Waterproof construction adhesive
• 3" deck screws
• 2" spiral nails
• 2 pairs of hinges
• 2 cupped magnet sets
• Paint
• 8 bags of fast-setting concrete mix
• Latch

The Ralph Lauren garden gate designer had done much of the work for me, but I planned to simplify the design a little. The sign above the gate is obviously unnecessary, I didn't need the fancy detail at the end of the arches or the lights, and the gap under the gate needed to be smaller to keep the dog in. There was no information on the dimensions or construction details, so I made those up as I went along. I used the canvas in Fusion 360 to get the basic shape, then scaled it to the size I wanted and tidied everything up. The depth of the arbor would be half the width of the doorway. There was no way I was going to be able to make the arches out of a single pieces of wood, as the arch was 480 mm (~19") high, so I used lap joints for the arches and for the door. Lap joints are really strong, and waterproof construction adhesive and Miller dowels were used to pin things together.

I installed 3 12' long 4×4 posts in the middle of the existing fence (I would have used 10' posts, but the store was out). The fence was in decent condition, so I reused one of the existing posts. The soil where I am is very poor quality, lots of clay and stones and small boulders, so I ended up going down ~650 mm (26") before calling the hole digging a day. Each post was installed using 2 bags of Post Haste concrete mix with some brick fragments thrown in. Gaps between posts were 1140 mm (~45") and 500 mm (~20"). The short post I extended with a 4×4 offcut, some dowels and waterproof construction adhesive.

I designed these in Fusion360 (see Step 1), and broke each arch into 4 pieces that could be cut out of a piece of 2×10 pressure treated lumber (dxf file attached). I planed the lumber to improve the surface finish and to get it reasonably flat, taking about 1 mm (1/32") off each side. I cut the 8' length of lumber into 3 pieces using angled cuts so I could get 3 half-arches out of each piece. Each piece was fixed to the table using 3 screws and the outlines cut to a depth of 30 mm and the edge of the lap joint cut to a depth of 18 mm. That took 20 minutes per piece; you could of course cut deeper and completely cut out the lap joint, but we decided to release the pieces from the wood using a bandsaw and finish the cuts using a flush-cutting bit on the router table. This was really fast. The laps were cut on the table saw (also very fast, though take the time to make sure your saw is set up perfectly to cut halfway through the piece). Cut 8 pairs of pieces in total. No mirroring requiring; that is built-in to the design, just flip one pair of pieces and it will assemble perfectly with the other pair.

Dry fit the pieces and predrill the holes for the Miller dowels. Liberally add waterproof construction adhesive to all faces that meet. Tap in the Miller dowels, leave to dry. Repeat for 4 arches. Scrape off excess glue.

Leave the glue to set up overnight. Clean up surfaces with a sharp chisel, then sand thoroughly using coarse sandpaper. Pressure treated lumber comes with lots of puncture marks here, so I filled those. If you've done it well, the joins should be barely visible. We painted ours before putting them up.

Similar workflow here to the arches (dxf files attached). We just made the curved cuts on the ends of each piece into lengths of 2×4, and made all the straight cuts on the table saw. I used the router table to cut stopped dadoes into the inside of each piece to hold the panel material (18 mm thick tongue & groove cedar planks). Same assembly procedure as before, made a bit trickier because of the panels.

Your gate will be a little too wide if like me you did not account sufficiently for the hinges. That's OK! Just trim them down with a table saw or circular saw or hand planer to the right width. Add the hinges and hang. I recessed the hinges with a router to make the gap between post and gate a little less wide, but this is optional. You can use any style of hinge you like. I used some self-closing ones made of a heavy-duty polymer. Don't cheap out here! You want the gate to feel rock solid, so a bit of over-engineering won't go amiss.

The gate did swell slightly over the winter, so I had to trim it again, repaint the exposed edge and reposition the latch to account for this. You could avoid this if you cut the gate with a wider gap (say 1/4", 6 mm) between the two doors. I had left about half that initially.

The gate has 11 crosspieces. In the original they are square, there are more of them and they are unevenly spaced. I made ours octagonal in cross section (38 mm, 1.5" across). They protrude 80 mm at either end and are spaced 183 mm apart (use a flexible tape to mark positions). They were secured with deck screws. Adding these made the whole arbor really rock-solid. Again, these were painted before mounting.

I filled in the sides of the arbor with some simple cedar lattice held in place with 18 mm (~3/4") trim.

I wanted a way to unobtrusively hold the gates open, and opted for magnets. I recessed one on the back face of each gate and the back posts. These have been really great. The gate is held closed with a simple hasp.

You've built an arbor, now grow something over it! We had a clematis that was strangling a climbing rose next to the arbor, so we pruned back the rose (roses are very hardy and can survive harsh pruning - I thought they were delicate until I saw a neighbor who had beautiful roses "pruning" his with a hedge-trimmer) and draped the clematis over the arbor.

Always a good idea to have a path through a gate, because it is hard to keep a lawn alive with lots of foot traffic. We added a rustic garden path, see this instructable for tips on how to do this (simple if your path is flat and straight, a little trickier for curves and slopes).