I just finished this quick cat scratching post, I have built other more common ones covered with carpet, but our cat Salem is eating the fibers and barfing them up at night, no more carpet for kitty! We found the card board insert at the pet store, it is designed for a floor type toy for cats and thought I could have the best of both worlds, the first plan was to build the entire unit from fiber board so it would be splinter free, but the stuff will not hold screws well on edge. Out of frustration I picked some 1×8 scrap out of my burn pile for the cross section. It worked out well for a one-off project, my hopes are to make an arts & crafts style post of oak with a low pile Oriental rug that will be changeable when it wears out.
Thanks for looking