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Merge remote-tracking branch 'origin' into revarbat_dev

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Garth Minette 2022-06-07 13:28:31 -07:00
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screws.scad
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@ -4,7 +4,7 @@
// Included is a function for calculating the standard dimensions of screws including the
// tolerance values that are required to make screws mate properly when they are formed
// precisely, so if you can fabricate objects accurately then your screws will mate
// with standard hardware without the need to introduce extra gaps for clearance. Those
// with standard hardware without the need to introduce extra gaps for clearance.
// Includes:
// include <BOSL2/std.scad>
// include <BOSL2/screws.scad>
@ -94,10 +94,15 @@ include <screw_drive.scad>
// in cases where no default exists you can specify it.
// Subsection: Tolerance
// Without tolerance requirements, screws would not fit together. The screw standards specify a
// nominal size, but the tolerance determines the actual size based on that nominal size. Screws
// modeled by this method will have dimensions consistent with the standards they are based on, so that
// they would interface properly if fabricated by an accurate method. Different tolerance designations
// are used for nuts and screws, and also for UTS and ISO.
// nominal size, but the tolerance determines a range of allowed sizes based on that nominal size.
// So for example, an M10 screw with the default tolerance has an outside (major) diameter between 9.74 mm and 9.97 mm.
// The librasry will use the center point in the allowed range and create a screw with a diameter of 9.86 mm.
// A M10 nut at the default tolerance has a major diameter (which is the inside diameter) between 10 mm and 10.4 mm.
// Shrinking the major diameter of a screw makes the screw loose. Shrinking the major diameter of a nut, on the other hand,
// makes the hole smaller and hence makes the nut tighter. For this reason, we need a difference tolerance
// for a screw than for a nut. Screw tolerances Screws modeled by this method will have dimensions consistent with the
// standards they are based on, so that they would interface properly if fabricated by an accurate method. The ISO and UTS
// systems use different tolerance designations.
// .
// For UTS screw threads the tolerance is one of "1A", "2A" or "3A", in
// order of increasing tightness. The default tolerance is "2A", which