Stove burner valve extension

[58limited]

Does anyone know where to find these? I am missing one knob for my Wizard stove and found four replacements but the original knob has a 1" extension and the new knobs are flush. I need to extend the valve stem so I can use the new knobs. The end of the stem is 'D' shaped. The knobs that fit this stove are an unusual size (2 1/4" diameter) and there are very few like them available either with or without extensions. The only extension I've found is for Wolf brand stoves. It is .350" in diameter and my knob stem is .3135" diameter (5/16").

 

If I can't find any of the correct size, I'll buy the Wolf ones and make them work somehow.

http://www.ebay.com/itm/350129412730?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649