25 to 39mm step up?

[The_Cheat]

Hi guys,

I have a lensboard from an old model of Durst enlarger, which have a hole that could only take in 25mm thread enlarger lens. Unfortunately, I also have a Rodenstock lens that have a thread size of 39mm. Anyone know of any unorthodox 25 to 39mm step up ring? Or do anyone know where I could possibly drill the lensboard to fit a 39mm thread size?

Thanks