Someone must have put the world's most pathetic curse on me; to always live in a home without a place to hang a bath towel. The problem is that landlords will often ding you for making any modifications. This thing can be removed and leave no trace except inside the door jam, practically unnoticeable and easily repaired. It's also useful if there is no other space to install a towel rack.

The towel bar is attached to a new door hinge fastened to the door jam in the gap left by the actual door hinges. As such it is free to swing 90 degrees. If your door swings much beyond a right angle, the part holding the rod would have to be redesigned Also, being anchored at only one end, you can't put a lot of weight on it. But it easily handles the weight of a wet bath sheet.

The first thing you should check is that the gap in the door will accommodate one blade of your hinge. I included a picture of the hinge from home depot that I used. The screw holes in the base may not be positioned correctly for another random hinge. The bar is 1" pvc pipe cut to the desired length -- I suggest just short enough to clear the door knob.

Try to select a filament with a good resistance to creep. I used the best filament I had on had that looked pretty good and shouldn't sag easily. To get as strong a part as is reasonable print with 5 walls, 1mm top and bottom, and fairly high infill. Configure outer walls to print first. Printing so many walls also helps give a good anchor for the screws that self-tap into the base.

There is a little tab on the hinge that will need to be ground off or hammered flat. Before drilling any pilot holes in the jam, be careful that the hinge is oriented properly to line up with the holes in the part and is free to swing over the full range that you will be using. If door doesn't have a big enough gap, you can recess the hinge like the actual door hinges; though that obviously would leave a mark.

It would be possible to arrange for the bar to follow the door when it closes but I want it to be able to remain at 90 degrees and I don't feel up to designing a method to have both features.

I am not proud of the aesthetics of this thing. I hope someone takes the idea and creates a better-looking design. I am, however, very pleased with the device itself. I hope someone finds this useful.