This is a support I designed to hold your Dremel rotatory tool in an upward vertical direction and used it in this position. Is made out of two pieces, a flat base in the rear and the tool holder, there are two versions of this holder, one uses the standard cap that comes with your typical Dremel tool, and the other uses the cap that comes with the Detailer's Grip Attachment 577 (The one in the pictures, if you don't own it, I can't recommend it enough, its super useful). You only need one!
The base can be nailed or screwed to a table, but I recommend use a cramp and don't drill your workstation. The two pieces can be held with a screw, or glue together. You can also print both pieces as one, but that will need a lot of support.
I have plans to add a little work table to hold pieces in complete horizontal, that what the pill-shaped holes are for, or design a longer and bigger custom cap, but so far it works like it supposes to. Hope you find it useful.