These bolt kits consist of 8 hex head, silver plated M8 x 1.25 bolts, 20 mm long, and 8 stainless steel flat washers. They are properly sized for connecting ISO-F 80 hole through flanges and fittings to the threaded holes in ISO 80 gate valves. Gate valves have standardized flange, thread, and thread depth specifications. These bolt kits are correct for connecting any gate valve of this flange type and size to an unthreaded flange of the same size, no matter the manufacturer. A centering ring with O-ring seal is required and sold separately.

The length of the bolts in this kit are specially measured so they tighten ISO-F to ISO-F flanges fully but don’t bottom out in the blind threaded holes of the gate valve’s flange. The bolts are silver plated to prevent galling or seizing of the bolts and to make them easier to loosen, especially if they have been heated to bakeout temperatures.

If the gate valve is to be connected/adapted to an ISO-K type flange, such as might be found on a turbo pump, single claw clamps with longer bolts and centering rings are required.

These bolts are for tapped threaded hole flanges and follow ISO-LF standards for flange sizes of NW-80. ISO flanged vacuum fittings are commonly used to build process vacuum plumbing and systems for industrial applications. The fittings are quick to assemble using double claw clamps and a centering ring (please see top right figure - click to enlarge). The Viton® centering ring contains a rubber/elastomeric o-ring. The ISO standard sizes for large flanges are NW-63, NW-80, NW-100, NW-160, NW-200, NW-250, NW-320, NW-400, NW-500, NW-630. These vacuum fittings are made of corrosive resistant stainless steel.