Y-shaped top stops look best on the coarse teeth of Delrin zip fasteners. YKK produces these color lacquered top stops for its Vislon injection molded zip fasteners. However, you can also attach these YKK top stops to any other zip fastener with coarse plastic teeth.
We will show you step by step below how to attach such an elongated top stop to the upper end of a Delrin zip fastener.
First, remove some of the molded plastic teeth by means of end cutting pliers, also known as forehead cutter. Ideally, during cutting processs you should leave the filler cord undamaged at the edge of the zip fastener you make free from teeth, because the top stop sits more reliably on an intact filler cord than on a thin ribbon edge without filler cord.
Place a top stop between the jaws of suitable pliers. The jaws of the pliers should be at least as wide as the top stop, so that the jaw contour does not imprint on its surface. If the inner surfaces of the jaws are not smooth, e.g. are
grooved like in water pump pliers we use, then protect the surface of the top stop with a piece of cardboard or leather.
Hold the pliers with the top stop in one hand. Use your other hand to slide the zip fastener tape through the pliers into the top stop. Align the elongated top stop with the edge of the tape so that it does not sit askew on the tape later.
Firmly compress the top stop with the pliers. To make sure that the large top stops for Delrin 9 and Vislon 10VF zip fasteners are really tight, you may need to use both hands to apply pressure to the pliers. When such high pressure is used, the surface of the top stop remains intact only with the above-mentioned protective liner of cardboard or leather.
One top stop on only one side of the zip fastener chain is functionally sufficient. Of course, you can also attach a top stop on the other side of the zip fastener chain. It is more secure this way, should one of the two parts loosen. Besides, some people find it optically more pleasing.
YKK top stops used here are so narrow that they can dip into the slider when you close the zip fastener completely. It is aesthetically appealing on the one hand. On the other hand, you should not use these top stops on separable zip fasteners, for example in jackets. Because if you unhook the zip fastener at the insertion pin & retainer box, the slider on the single zip fastener chain can slide not only to the top stop, but also over the top stop, because it is so narrow. Therefore, for open end Delrin zip fasteners we recommend either stirrup-shaped or universal U-shaped top stops.