For easy adaptation, try to find a reversing T mount adapter that fits your lens.

This ring by Vivitar was part of their bellows system, has 52mm male threads for the lens front and a male T thread (M42X1) on the other side. They were made in several sizes to fit most lens filter threads.
Since I didn't have the right one using a 49mm thread, I just used a 49 to 52mm step up ring.

Standard Maxxum T adapter on the right