Abstract: A handle shaft assembly includes a tube spacer, a handle shaft, a stuff box, and an operational handle. The stuff box may be configured for insertion into a through-hole within a bottom loading coupler body and include first and second stuff box ends defining a cylindrical cavity. A first sealing member may be positioned on the first stuff box end, and a second sealing member positioned on the second stuff box end. The tube spacer may be configured to be positioned within a blind counterbore of the bottom loading coupler body. The handle shaft may include a first end positioned within the tube spacer configured to be positioned with a blind bore of the bottom loading coupler body, a linkage section configured to be coupled to a drive linkage of a poppet valve assembly, and a second end extending through the cylindrical cavity of the stuff box. The operational handle is mechanically coupled to the second end of the handle shaft.