hope'w window operator

I have a home built in the late 1930s with Hope's window operators on steel casement windows. Several are not working and disassembly indicates the arm gear is worn down to to lack of lubrication and window sticking. Is it possible to replace the arms? Is it possible to buy replacement operators? I have looked through your website and do not see a similar operator. Note the mounting screws are in a vertical plane. I will attatch photo of my operator for your review. Thanks in advancel.
scottt

Close in design but wont work. Note distance between mounting holes is 3.5" on your 39-020 part. The distance on the original Hopes part I have is 2 3/8". Since the mounting base is integral with the window frame, that can not be modified. I have found one of mine replaced with a Hopes operator with the number 5896 cast into the bottom. Please look again and see if something might be available to replace these. Thanks in advance.
Scott Main

Hello,
I have several casement window crank operators that are stripped. The handles are fine. The stripped part is the distal (fine) end of the 2-inch screw gear. It's worn down so much that it won't catch the teeth of the arm gear. Is there any know replacement for this 2-inch screw gear? I don't mind taking the things apart. In fact I'd rather do that than replace the operators with new ones. Any thoughts?.