Read the second number. This is either the number of threads per unit of the distance between threads ; also known as the thread pitch. Unified screws give the threads per inch. Feb 03, 2016 Were good old BSP not this NPT crap! Its also the only thread form in modern use with a 55 degree thread over here. Seeing as most of the rest of the world uses metric, its patronizing at least to be told by a silly wanker of a american, that at best just represents some 300 million of the worlds 7 billion population what the norms are. THREAD CALLOUT ON SHAFT (self.SolidWorks) submitted 3 years ago by indianadarren Does anyone know how to get the thread callout on a drawing sheet when the thread is external, that is, it has been applied to a shaft?

Mar 11, 2007 I agree with what you just put Ctopher, if in doubt put a section and dimension it there. However, I still stand by my interpretation of the OP and while I'd probably use the depth symbol rather than say 'deep' I would use pretty much the same callout if I needed to better control the length of thread than just saying 'min full thread '. Understanding Tapping Screws - Fastener Mart Self drilling screws , also called Teks, have a tip that resembles a drill, and often have spaced threads , like sheet metal screws . In a single time-saving operation, these screws drill, tap and fasten. Do not use self drilling screws in blind holes (holes that do not pass through the material). Screw Thread Design Screw Thread Fundamentals A screw thread is defined as a ridge of uniform section in the form of a helix on either the external or internal surface of a cylinder. Internal threads refer to those on nuts and tapped holes, while external threads are those on bolts, studs, or screws .