Most DSLR Rigs use handle grips very similar to bike handle grips. In fact if you threw a bit of cash down, you can get Bike grips better than rig handles. Now how do you go about making your own custom set? Well first you need to get them down to fit the 15mm standard, so the video above by Vimeo member Jarrod is one way to accomplish this with a nice pro look. This technique requires a pair of 15mm rods and a pair of 90 degree clamps, so by no means dirt cheap, but you can end up with something worth much more than what's found in current retail. One way of saving a few bucks is to locate a single rod and cut it in half. [Thanks Jarrod]
You can find a variety of inexpensive 15mm Rig Rods and Clamps new and used at the auction site (click here).
15mm Rods and 90 Degree Rig Clamps