BA Screw thread gauges: even numbers

prusaprinters

These are handles designed to take British Association (BA) Screw Threads: even sizes. so that they can be used as crude Go gauge to check what internal thread size nuts and other inserts have been cut to.  To construct the gauge you will need the following:Printed handles of the appropriate size for the gauge you wish to makeMachine Screws of the appropriate BA size with a length of at least 1 inch (2.5 cm)Then it is simply a case of cutting the end off the machine screw and then inserting the the headless threaded bar into the handle.  I would suggest the cut end goes into the end of the handle so as make insertion into nuts a lot easier.  Use a dab of glue to hold them in place.  British Association screw threads are a set of small screw threads the largest being 0BA at 6 mm diameter. They were, and to some extent still are, used for morse code keys, miniature instruments and modelling.They are unusual in that they were probably the most "scientific" design of screw, starting with 0BA at 6.0 mm diameter and 1.0 mm pitch and progressing in a geometric sequence where each larger number was 0.9 times the pitch of the last size.