When I noticed our cats really seemed to like the left over felt from my Kindle and laptop sleeve projects I decided to use it in a cat tree to replace the tiger striped abomination under our living room window.
Step 1: Inspiration
The felt is F-13 from Sutherland Felt. It's great stuff.
Step 2: The Pillar
I started by creating a paper pattern and gluing it directly to the plywood close to the edges to conserve wood.
The inside corners were cut with a jigsaw leaving only straight cuts that were handled with the circular saw and a cutting guide. This initial piece serves as a pattern for the other two. Subsequent layers start out as rough cut pieces large enough to screw/glue the original onto with an overhang around all the edges. A flush trim router bit was then used to remove the excess wood.
Step 3: Platform Layout
I wanted to make sure they were both directly over each other when assembled.
First I found the platform centers. To help with layout I aligned the platforms to the edge of the workbench. The pillar was positioned making certain the top and bottom edge of the pillar lined up with centerlines of the platforms. Then I just struck a line and used the pillar itself to layout the box where contact would occur.
Step 4: Attaching Platforms to the Pillar
Pilot holes were drilled inside the boxes drawn in the previous step, and countersunk on the opposite side.
To get matching pilot holes in the pillar start by clamping it in the vise. Put the corresponding platform on the pillar end and line it up so the end is inside it's layout box. Drill back through the pilot holes in the platform into the end of the pillar.
Start the screws into the platform and drive them till they're protruding through the other side about 1/16". The ends of the screws will fit into the pilot holes in the end of the pillar ensuring good alignment.
Step 5: Attaching the Felt
The felt for the bottom platform will require a hole for the pillar. Begin by cutting out the piece using the platform itself as a pattern and a utility knife with a nice sharp long blade. Use the layout box to mark lines for the hole keeping the edges of the felt lined up with edges of the plywood.
3M 77 spray glue was used to affix the felt. Spray both surfaces. Take your time. The felt and glue are somewhat forgiving, but take your time to get good alignment. Overhanging felt can be trimmed up afterwards as well.
Step 6: Time to Wrap It Up
The rope is attached using screws on the side I knew would be facing the wall. At any rate they're not very noticeable.
I needed about 75' of sisal rope, so two skeins or whatever you call them. This was by far the most annoying part of the build. You need keep a tight wrap and the sisal does not like 90 degree corners so you have to babysit it the entire time.
Step 7: Cast Out the Abomination
The cats dig it.