Thread Gages are suited for deep holes.
Press Release Summary:
Able to be used at depths that exceed hole diameter, Multi-Ball(TM) products inspect screw threads for size, location, concentricity, or runout. Thread micrometer measures size, taper, and out-of-roundness of threaded holes for most sizes up to 1 in. dia. Location gage determines location/orientation of threaded hole axis using expanding pattern of balls that come into contact with thread flanks and automatically adjusts to hole size.
Original Press Release:
MULTI-BALL(TM) Thread Gages for Deep Holes
INDIANAPOLIS, IN - March 31, 2004
Deep screw threads can be easily inspected for size, location, concentricity, or runout with the use of Multi-Ball thread micrometers and location gages. Multi-Ball products can be used at depths that far exceed the hole diameter.
The Multi-Ball micrometer is used to measure the size, taper, and out-of-roundness of threaded holes. The simple design is small and lightweight weighing just 4 - 14oz. for most sizes up to 1 inch diameter. It requires no extra accessories and is always ready for immediate use. As a result, there are no additional costs related to set-up, assembly, calibration, training, and maintenance.
The Multi-Ball location gage is used to determine the location or orientation of a threaded hole axis. Typically used at coordinate measuring machines, it aligns its axis with the internal thread axis by expanding a pattern of balls into contact with the thread flanks and automatically adjusts to varying hole sizes. This method eliminates the errors that can be induced by other gages when they shoulder against the workpiece or when they deform the thread with tapered engagement.
Both Multi-Ball products can be adapted to many types of unique or difficult applications. Often standardized components can be used to produce custom gages, which reduces expense and lead-time.
Special thread pitch/diameter/length combinations, left-hand threads, multiple start threads, and deep holes are just a few examples of these specialty instruments.