Hopefully this falls under "carpentry" haha but if not I apologize. So I built this tower for my new kitten but it has a bit more wobble than I'd like it too!
This is the general plan I based it on:

And here it is assembled!
I want to add some supports but figured I'd brainstorm it first. I was thinking about adding two 2x4s along the bottom of the posts to add some rigidity, but I'm also wondering if I need to add a diagonal support perhaps a ramp between two levels, any advice or tips would be appreciated!

Thanks in Advance

 

Welcome to the forums.

How did you assemble everything?

 

Thank you! So the the posts are all 2x4s, each level is a solid piece of 1/2" (I believe) plywood, and each level is nailed to the 2x4 post

 

I would have used screws and maybe some glue instead of the nails but seems too late for that now. Would it help to tie the two bottom boards together or is the wobble higher up?

 

Haha yes it may be a touch late for that, I was mostly just using what I had on hand, so far I only have about $20 into this thing although I'm sure i could turn it on its side and get to the bottom and screw the base together instead of the nails I'm currently using. The wobble does seem higher sort of on the main L shaped level, it seems to me to be more pronounced side to side wiggle on the side of the whole thing that is against the wall if that makes sense!

 

Add diagonal bracing to the bottom section closest to the wall. Attach the bracing to the posts on the back side against the wall for better appearance.

 

I agree, diagonal bracing should help a lot, wood or even steel L brackets.

 

Most home centers and building suppliers sell various steel brackets. Screwing some into the corners underneath. You can also make something similar out of wood though the steel ones are probably easier to work with.



This style will help support each level and because of the solid web of steel as a diagonal it can provide a lot of strength to resist racking. They are relatively small and might not be too objectionable. If you don't like that galvanized steel industrial look you can use decorative shelf brackets.





The key is to use screws to attach any support brackets. Racking and wiggling will slowly pull nails out over time but screws will hold solid.

 

My father would have spent twenty minutes lecturing me if I had used nails. Too late now but I'm sure you will remember next time. My father kept a large assortment of pan head sheet metal screws but being more modern I always have boxes of deck screws in 1¼", 1-5/8", 2", and 3" on hand. Another great advantage of screws are mistakes are much easier to correct. Hope you don't mind the old man advice.

 

Looking at the pics, you could probably get a fair bit of rigidity just putting a base of 3/8 or 1/2 inch plywood under the two base segments, screwed in from underneath since your uprights are much taller than the "baseline" design before they're tied together front to back. In addition to that, you could triangulate the sides at a couple pints without obstructing the works too badly, the locations sketched in with green should give you a pretty solid setup in combination with a plate connecting the bases, if there's any lateral wobble, adding a brace on the back of the legs where the blue line is sketched in should tighten that up.