Abstract: A gate for irrigation pipes adapted to be moved between open and closed positions over an opening in the pipe. The gate includes a carrier plate having a sealing boot around its periphery which will engage with the interior of the pipe. A slide member engages the exterior of the pipe and is connected to the carrier plate by a plastic screw. The screw includes long pitch square threads so that the slide member and carrier plate may be quickly drawn together for installation or adjustment. The screw head is received in a circular recess in the slide member. As the screw is tightened a pair of small buttons on the underside of the screw head interact in ratcheting fashion with ridges formed in the recessed area of the slide member to prevent the screw from loosening in service. The recessed area is formed at an angle such that the screw head engagement tends to place more pressure on one end of the gate, which is further from the screw. The screw head includes a pair of spaced opposed walls which define a slot.