Bolt Length Attribute (BTHK)

The BTHK (Bolt length) attribute is used as follows:

• Components with blind holes have the tapping depth assigned to their BTHK attributes.

• Jacking bolts have their BTHK set to the sum of the flange/facing thickness and the required opening gap.

• Wafer components with no special bolting needs do not require a Bolt Pointset. If supplied with a Bolt Pointset, a BTHK value of zero indicates that the face-to-face dimension of the wafer component is included in the bolt length calculation.

• Wafer components with special bolting needs require a Bolt Pointset, with BTHK values assigned only to the respective Bolt Points affected. For example, a wafer lug valve with four bolted through holes and four tappings for cap screws on each side requires eight Bolt Points. The four bolted through numbers have their BTHK set to 0. The cap screw numbers have their BTHK set to the tapping depth. See the Example Wafer Lug Valve image in Example Wafer Lug Valve.