This is a hub/spinner for playing dominoes, especially Mexican Train and other variations. It's sized for dominoes we already had, which were approximately 26mm x 51.5mm x 8mm, but in theory it could be scaled to any size. The outer dimensions are 100mm x 100mm, the main plate is 2mm thick, and the ridges stand up an additional 1mm.
Monoprice Maker Select v2
As long as you have good bed adhesion, this should print without a raft; however, if you have young nieces like I do, they WILL want to paint the raft like a flower if you print one (see third picture).
The dominoes set we have came with one of these, but it was lost after being played with by the aforementioned nieces. Armed with only my vague recollection of what it had originally looked like, I decided to design and print a new one. I started with the full size, which had to fit in the tin in which the dominoes are stored. Once I settled on 100mm x 100mm, I trimmed it into an equilateral octagon. I measured the dominoes and left an extra 1mm in each direction for a center hole of 27mm x 52.5mm. From there, I created 27mm recesses 10mm into each side, which left enough material between recesses that I felt the remainder wouldn't be snapped off too easily. Then I decided on a base height of 2mm and a ridge height of 1mm, which results in a total of 3mm ridges. Since our dominoes were 8mm thick, that left 5mm to be able to grab onto when taking the middle domino out, which was plenty.