Braces for the Z axis of the Wanhao D9, using M10 threaded rods. There are other braces on this site, but using imperial rods! Which I cannot get in the UK, and besides, ewww. Also they didnt seem solid enough to me. These are printed as single pieces, designed for the 300 version - I dont know if they will fit the 400/500, you'll need to check! Probably wont be any issue though.
The base is printed with an M10 thread designed in, you will almost certainly need to use an M10 tap to clean it up. A cheap way to make your own tap is to take a spare section of rod, and use a dremel or whatever to cut multiple slots into it. Then try threading it in. Might take a while though, a real tap attached to an electric screwdriver will be much easier!! You'll likely have spare rod, I cut both of mine down from 1m pieces bought at local hardware store (needs about 69Cm each, recommend you measure anyway). Pretty cheap. 5x M5x15mm screws to clamp it down on each side, along with suitable nut bits underneath. I had spares hanging around from previous project, but if you dont have anything then just do a search for t-slot nuts. Also two M10 nuts per side to hold the rod, obviously.
Base section print orientation is obvious, but the upper part should be printed on its side. As per thingiview, but the other way up - look at the holes, you'll see little roofs added to them to aid printing with overhang issues. These should face up. Designed such that the top brace shouldnt "need" support, although one area did get a bit messy (see final pic, just below the top nut). If you can add support just to this section, might help, or support up to a certain level layer maybe, but not a big deal.
Also see the ribbon cable, wrapped around the threaded rod. Seemed best way to do it to me! Finally, suggest using a set square to get right angles when doing everything up. Its a bit of a pain, as there are no easy surface to just press it up against, but still a good idea. If you dont have one, a sheet of A4 paper would probably work to give you a right angle. In fact this might be easier....
Other D9 upgrades I've done: