Awning Window Help

I have awning windows on my home that are about 20 years old, plus or minus a few and I need some parts. I looked for a name of the windows and all I can find is a sticker that says Thomas Clad. I have about 5 windows where the crank is stripped thus not allowing the windows to open. The parts that are stripped on all the windows are the little round lock screw (that is what I think it is called) that is screws down around the crank piece that is protruding (this is where the handle attaches). I have looked everywhere locally and cannot find the parts. Do you carry these an if so, how much is each one. I cannot get the ones I have screwed back into the mechanism as they seem to be stripped. I appreciate any information you can reply to me with.