Vacuum Fittings

Below are the sizes for the diameters of the various NW, QF, KF and ISO vacuum fittings.  We have included a file you may download that shows, to scale, the various sizes.  This chart also lists the physically measured diameters of the flange so you can use it to review what you have there used a ruler or calipers.  There is typically enough differentiation in the size of the diameters of the flange compared to other sizes of flanges to easily determine one NW size from another by simply by measuring with a ruler, scale or calipers.  Exceptions are some of the oddballs.  The NW10 size, which is not often used, is many times satisfied with standard NW16 parts. 

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