Inside Micrometer
Valve guide bore can be measured using a bore gauge. The bore gauge is inserted into the valve guide, and the measurement is taken by expanding the gauge until it makes contact with the inner walls of the guide. The bore diameter can then be read directly from the gauge.
Generally speaking, gate valves in larger sizes are full bore unless you order a reduced port. You would always use a full bore gate valve for hot tapping purposes. or you would use a full bore gate vale for runinig a pig in pipeline.
In Full bore ball valve, The bore dia will be same as internal dia of the pipe.In reduced bore, the bore dia is reduced than the ID of pipe.
For Ball valve only,as it gives more full bore flow,unlike wedge block,slow operating in Gate valve.
NB is nothing but Nominal Bore.
NB stands for "Nominal Bore" and refers to the nominal size of the valve in a piping system, typically measured in inches. It represents the internal diameter of the valve or pipe. It is an important parameter used to select the right valve for a specific application.
They would not generally release that information to the public.
valves are available in three types first is full bore equal to 100 percent opening normal bore/port equal to 80 percent opening reduced bore equal to 60 percent opening
This is a tool used to align the cleaning rod with the bore so that it doesn't rub against the sides of the bore when you pull the cleaning rod in and out. This prevents damaging the bore during cleaning.
Inside micrometer
Use full bore for applications where pressure drop should be minimum (such as in the suction pipe of a pump with required NPSH very close to available NPSH), or for pipes which could be cleaned with a pig (so that the pig doesn't get stuck on the valve). In other applications a reduced bore should be OK.
If there was no damage to the cylinder bore then you will not need to bore it oversize.If there was no damage to the cylinder bore then you will not need to bore it oversize.