I’m replacing a tub, and a hub joint on the 4″ cast iron vent stack protrudes into the alcove a little too much to allow the tub to fit (the old tub was tall enough to ride over the joint).
Can I grind off about 3/16″ of the hub joint, on the side where it blocks the tub installation, without destroying the structural integrity of the joint? The total pipe thickness is 1/2″, it’s an oakum and lead joint, with about 16′ of stack above this joint (I’ll make sure there is a riser clamp holding the pipe in the attic). I don’t need to modify the pipe diameter, I only need to reduce the diameter of the widest part of the hub joint itself.
Thanks! Gary