We have a large cat climbing tower which had a loose post, causing the whole tower to wobble when a cat climbed on it. The cylindrical support posts and horizontal cat shelving are held in place by nuts and bolts; the nuts are secured in plastic inserts on each end of the posts.

One of the post inserts was broken, so it was time to design and fabricate a new part!

Click images for larger view

Post inserts are supposed to look like this; plastic with a steel nut in the centre.

 

One insert was broken and most of the plastic material was missing. The nut and surrounding plastic were still attached to the bolt, but no longer effective in binding the post to the above horizontal cat shelf.

 

Designing a replacement insert in Lightwave 3D – this is the outer part.

 

Base bottom (shown upside down), base top and nut recess (shown upright),
base inserted into outer (shown upside down).

 

3D printed outer with washer, inner with nut. To ensure that the nut doesn’t turn freely when the bolt is tightened, the inner has four lugs which fit into four corresponding slots in the outer.

 

Assembly of 3D printed parts. The inner was Superglued into place to ensure that it didn’t fall out inside the post when turned upside down and hammered into place.

 

Alignment and insertion of parts into the post cylinder. Designed as a jam-fit and with slightly tapered sides, the insert was hammered into place with the bolt removed, using a rubber mallet. Held firm by Superglue, the inner and its nut remained in place, rather than dropping out into the hollow post.

 

CAT-Scanned and approved! Yellow circle shows location of repair.