I wanted a simple camera mount to attach to the back plate of the printer so the camera would be near the level of the printer bed so I designed a simple L-shaped bracket using Fusion 360.  

I designed a recess for a hex nut and did two versions - one with the hex nut above and one below the mounting face.  The hex recesses are a slight interference fit. I heated a nut and then pulled it into the recess with a bolt to make a semi-permanent installation.

I used hex head 12-18x1/2" self drilling  screws to attach the mount to the frame because I had them on hand.  The holes in the mount are sized so the screws don't actually self drill but do self tap.  Sheet metal screws would also work.

I have included the Fusion 360 files so that you can make changes to hole sizes, leave out the hex nut recess, lengthen it to raise the camera location, or anything else you wish.

How you attach the camera to the mount depends on your camera base.  I happened to have a ball and socket mount and used a ¼" bolt from the bottom through the nut and clearance hole into the base of the socket.  My camera attaches to that.