Questions and Answers for Westbrass 1-1/2 in. NPSM Twist & Close Bathtub Drain Plug, Coarse Thread, Polished Nickel

A:  None of them! 1/2" Copper pipe measures 5/8" OD. 1-1/2" Sch 40 PVC measures 1.90". The Engineer in me knows that 1-1/2" NPSM measures 1-7/8"-11.5 Meaning the inside thread of the female receiving tube is 1-7/8" diameter and it has 11.5 threads per inch. The other commonly used drain thread size is 1-1/4" NPSM (also called 1-3/8" NPSM). It measure 1-5/8" -16 which is an OD of 1-5/8" with 16 threads per inch.

A:  Why does 1/2 in. Copper pipe measure 5/8 in. OD? Why is 1-1/2 in. Sch. 40 PVC measure 1.90 in. OD? Plumbers are not carpenters nor are they engineers. Even though the plumbers in the world call that size 1-1/2" NPSM coarse thread, the engineers in the world call that size 1-7/8"-11.5 UNC-2A. They are just two different ways of talking about the same thing from two different points of view.

A:  The overflow plate is purchased separately. We have several different styles to work with this drain depending on your drain needs. Please see D328-11, D329-11 or D980R-11.

A:  If your tub stopper measures 1-7/8" - 16 thread, Westbrass does not carry that size.

A:  model 79438cp-Z is made of zinc and is finished in Polished Chrome. The item on Home Depot's site is powder coat white.

A:  It is treaded to screw on to the pipe that comes up throw the tub. You need a drain removal tool to remove and install new one.

A:  This item doesn't use a nut or flange for installing. It goes into a brass or PVC bottom "shoe". It screws into that shoe and a thin bead of silicone sealant (like caulking) under the rim against the tub seals the unit to tub.

A:  Silicone does work perfectly...until you want to change it out again... good luck getting it off

A:  Plumbers putty has a petroleum base and the chemicals in it can leak and corrode the decorative finishes on products. A thin bead of silicone caulking works perfectly!