Why Does MB Sturgis Sturgi-Stay T-Fitting Have Male and Female Threads

Published 01/17/2019

Question:

I purchased the MB Sturgis Sturgi-Stay T-Fitting for Type 1 Valve - 1/4inch FIF and Disposable Cylinder Port Item # 103612-MBS from you. I noticed on the Type 1 male outlet side of the fitting there are also female threads INSIDE the fitting. Can these threads be used to make a more permanant connection to the regulator hose instead of the external Tape 1 male threads? An if so, what is the thread type and size of the inside threads?

asked by: Ken B

Helpful Expert Reply:

The two threads you pointed out on the MB Sturgis Sturgi-Stay T-Fitting for Type 1 Valve # 103612-MBS are on the outside a Type 1, ACME fitting and on the inside a POL fitting.

A POL fitting is commonly found on the ASME tank used on motorized RVs to connect the propane tank valve to the RV regulator. Before the introduction of Type 1 fittings, POL fittings were the standard fitting for all propane tanks. Now, both types of fittings are featured on DOT cylinders. The POL fittings are the threads on the inside of the DOT cylinder's connector. Also note that POL fittings feature left-hand threads.

A Type 1, also known as an ACME fitting, is the fitting used on modern DOT propane tanks. These fittings are used today because they are less prone to leaks and do not require tools for installation like POL fittings. The Type 1 fitting uses the threads on the outside of the tank valve to connect the pigtail hose to the propane cylinder.

I attached a page that has all of the POL pigtails we offer for you to check out as well.

expert reply by: Jameson C