I had plenty of cardboard lying around, access to a laser cutter, and a new kitten - it was the perfect storm for my next project, a Cat Scratcher Tower. I made this at TechShop!

List of materials required is quite simple.

Cardboard - I used about 5 sheets of 24x18 (the size of the laser cutter bed), and I made two cat scratchers - I could definitely use some more cardboard. It is best to use the thicker variety of cardboard (like TV boxes), as the cross section is more substantial - you will need fewer of these to stack up, and the cross sections look nice too!
Wooden dowels - 2x 4ft dowels - you can get these at your hardware store - I got mine from Home Depot
Some scrap wood for the base and to act as a ballast - I found mine at the scrap bin at TechShop
Wood screws - 6 per Cat Scratcher - I used a total of 12 (plus a few more whose heads I ended up stripping! :-( )
Felt pads - to stick on the bottom to protect your floor

Tools:

Laser cutter
Drill/drill press
Screwdriver
Clamps

PS - I forgot to introduce my model - Lokelani, aka Loke is our new kitten that we rescued from Kauai when she was about 6 weeks old. She's now about 3 months old and is a rambunctious bundle of energy, and incredibly cute! It has passed the Loke test - didn't tip over when she decided to climb it. Thanks Loke!

Step 1: Laser Cut Your Cardboard

My outline was simple - a 4 inch round, with two 3/4 inch holes for the dowels.* You can go crazy with the shapes if you want! That's the beauty of the laser cutter. Cutting cardboard is a snap!!

I used the settings of 30/90/500 (speed/power/frequency) - it worked really well, scoring the cardboard just enough so that it was cut all the way through, but not burning/scorching it.

* Lesson learned about the 3/4 inch holes - Since I wanted to slide them through the dowels, I should have made them slightly larger than 3/4 inches - the fit was quite tight, but doable. But don't make it too much bigger, otherwise the cardboard is going to shift around.

Step 2: Prepare the Base

The base needs to be a bit strong and weighted down, as you don't want your cat scratcher to tip over when the kitty wants to sharpen its claws!

I found a bunch of scrap wood at the TechShop scrap bin, that served my purpose splendidly!

I used a base plywood board (I found two of them, identical in size, which is what made me make two of the cat scratchers)
Some rounded wooded pieces (to act as the "trunk" of my Cat Scratcher tree!)

First I marked where I would like the cardboard pieces to sit, on the plywood. I then used a drill press to drill a small hole (3/32 works well with the #8x1-1/4 wood screws that I used.

I then glued the wooded rounds to each other and the plywood base using wood glue, and then clamped them to set, for about an hour.

I then drove the wood screws in from the bottom, to secure the wood rounds to the plywood base.

Step 3: Finishing the Rest of the Structure

I cut two 4 inch rounds on plywood, on the laser cutter. These would form the base on which the dowels would be fixed.

I again used the cardboard cutout outline to mark where the center holes should be. Then, using the 3/32 drill bit, I drilled a couple of holes through the plywood.

I cut each 4 ft long dowel into 2 ft long pieces.

I drilled a 3/32 hole through the center of the dowel for a height of about 1-1/4 inch (to accommodate the wood screw). These were hardwood dowels, so I had to drill in stages, removing material as I went along.

After that I screwed the dowels onto the plywood base.

I then used a 1/2 inch drill bit to drill a couple of indentations into the top of the base piece. These would allow the screws from the bottom of the plywood piece to sit, so that the plywood would be flush with the base piece.

I then used wood glue to glue the plywood/dowel piece to the base piece, and clamp it down. I had to get creative with the clamping, as there wasn't enough room. A leftover piece of dowel came in handy for this. I left it for an hour to cure.

I then drilled a couple of 3/32 holes on the base, and then used wood screws to secure the plywood to the base piece.

Step 4: Insert the Cardboard Pieces and Wrap Up!

Now you can start inserting the cardboard pieces. Take care to line up the cardboard pieces such that the cross section contours match - this makes the finish that much nicer to look at.

Insert as many (or as little) cardboard pieces as you like. As your kitty grows up, so too can the Cat Scratcher Tower!

I didn't go higher than a 2 ft dowel, as the risk of it tipping over increases with height. 2 ft with a sturdy base was just fine.

Last but not the least, add some felt pads to the bottom of the base plywood, to protect your floor. Remember to add felt pads to the wood screws as well!

Your cat/kitten will love your forever!

Cheers,
Sridhar