Tuning Pegs - Wrench for Rectangular Shape

[EliorMagen]

Hello!

I'm working on restoring an heirloom zither; it's about 140 years old, and the tuning pegs for the accompaniment strings are all rectangular, about 5mm by 3mm. I am having absolutely no luck finding a tuning wrench that's anything other than square. Does anyone happen to have recommendations?

Thank you,

Rory

[Rudy Mueller]

Please refer to the posts on rectangular keys below in this section. The one remaining rectangular key I have is 7x5 mm. Regrets. You may have to manufacture one yourself.

rudi