Just wondering if the handle off my ball end post war tech and fat handle off my prewar tech will fit Gillettes open comb razors?
I put an Old Type (Thick Cap) head on a Fat Handle from a Tech and it fits nicely. I like it better than the ball end handle. Better than both of those is the Old Type Single Ring handle. Still searching for my favorite: Old Type Bulldog Handle.
If it's a three piece razor with a short stud, yes.
Old Type Bulldog and Single Ring handles are not interchangeable with other razor types since they're integral with the comb, but I guess you know that.