Doors and Windows - Crank on casement window

Purchased a partially remodled home. The basement windows were framed and concrete poured to level the framing with the window. Trouble is that the concrete is just below the crank preventing it from rotating completely. It stops at about the 5:00 oclock postition. I ordered a 5/16 long spline Window Crank Handle Extension (Prime Line 22252), but the splines aren't deep enough and it does not have a set screw (which I could tap and add). Does anyone know of a fix for my problem?

chisel and grind it out ?

maybe try a tee handle?

XS's answer about Tee Handles is a great option; it should do the trick. There are also "shortie handles" (that's what I call them) which are crank handles about an inch shorter than normal for those situations like the one you find yourself in. And as you already found out there are extensions, my least favorite choice.

There are various sizes of spindles, so one must make sure they get the correct one. Blaine Window hardware has dozens of different types at
http://www.blainewindow.com/catalog/itemlist.cfm?catid=16&compid=1&pcatid=15

They could probably assist you via email or phone to get the correct one. Or you could just browse their website for ideas.

Thanks for the Blainewindow site, but nothing for 9/16 splines. Will try the "T" idea.