NPT or National Pipe Thread, is a U.S. standard for tapered threads on threaded pipes and fittings. NPT goes back to 1864 when William Sellers created a standard for nuts, bolts and screws.
TPI stands for teeth per inch and no, that’s not how they measure a shark’s danger level. Teeth per inch indicate types of saw blades. Higher TPI blades leave a smoother surface but cut slower than lower TPI blades. Check out some essential bandsaw tips for your next project.
ASTM (formerly American Society for Testing and Materials, now ASTM International) is making sure every day items are safe for use—from toys to aircraft by developing standards through its base of volunteers. It has committees on 3D printing and nanotechnology.