I recently dealt with the same thing after not being able to find good replacement handles.
What usually happens is the steel post that mounts on the glass side eats up the inside of the handle which is made from potmetal.
I removed the steel post from the glass first.
I then took a section of 1/4" ID brass tubing--available at Ace Hardware, cut off a 1/4" length, then cut a lengthwise section out as shown below.
I then closed the tubing until it was the same diameter as the inside of the handle, cutting the open end of the 'C' until it fit.
Once the piece was inside the handle it acted like a bushing. I drove the metal post into the handle with a dead blow hammer until the roll pin met with the groove on the post and drove it in. I had to squirt some penetrating oil in there and work the handle a bit to loosen it up, then put everything back together.
The trick is to have the open ends of the 'C' aligned with the roll pin, so in the end there was an 1/8" gap at the ends. You'll understand what I mean once you see things for yourself.
I hope this helps you!
Jim