For such an item, it’s unlikely that Durst made the gears. They were likely ordered from a gear supplier.
It’s imperative that you keep the broken gear for measurement so that a proper replacement can be located and ordered. A machinery service company should have the proper tools to quickly measure it to determine the correct specifications for a replacement.
Since the Durst enlargers were designed and made in Italy, the gears used were almost certainly of the
Metric Module Spur Gear design. You might not find a plastic gear (though it’s possible), but there’s no compelling reason that the gear can’t be replaced with a brass or bronze gear. The Module System denotes the size of each gear (tooth size and diameter). You’d also need the thickness, shaft size, bore diameter, and gear-to-shaft attachment type.
Here is a U.S. supplier. You should be able to locate one in your area. If you consult a machinery service company, it should be able to measure the gear and order a suitable replacement.
https://www.mcmaster.com/products/spur-gears/system-of-measurement~metric/
If you’re successful, it would be useful to post the full specifications for the replacement gear so that others can do the same.
