It is adjustable and quick to make.
Step 1: Tools needed
12 Short Bolts
2 Short Metal Strips (In this case I just straightened 2 weak 'L' brackets)
4 Long Metal Strips
2 Large 'L' Brackets
4 Small 'L' Brackets
Tip: You could add washers for a tighter fit
Step 2: Assembling The First Side-Bracket
Face the small 'L' bracket away from the large 'L' bracket and attach with the nut and bolt through the very top hole. Face the bolt head away from the large 'L' bracket as seen in the second picture.
Make two of these - these will be your supporting frame for the body of the holder.
Step 3: Assembling the Main Body
Using the first picture as a reference, going from top to bottom:
Connect the short metal strip to the 2 large metal strips with the nuts and bolts nice and tight.
Connect the small metal 'L' brackets to the long metal strips from the first hole on the 'L' brackets with nuts and bolts.
Connect the second small metal strip to the end hole of the small 'L' bracket.
Remember, nice and tight!
Step 4: Attaching the Side-Brackets to the Main Body
Attach the side-brackets from the end hole of the small 'L' brackets to the third hole on the long metal strips (see first picture), repeat on the other side.