Helix angle the helix angle. The efficiency can be plotted versus the helix angle for a constant friction, as shown in the adjacent diagram. The maximum efficiency is a helix angle between 40 and 45 degrees, however a reasonable efficiency is achieved above 15°. Due to difficulties in forming the thread, helix angle greater than 30° are rarely used. Moreover, above 30° the friction angle becomes smaller than the helix angle and the nut is no longer self-locking and the mechanical advantage disappears. In helical and worm gears, the helix angle denotes the standard pitch circle unless otherwise specified. Application of the
38 Degrees above a flat-line membership structure. 38 Degrees also claims its campaigns are selected by its members under its "Campaigns by You". David Babbs is Executive Director. He signs off some emails, appears in the media and frequently speaks at local 38 Degrees events. He has also represented 38 Degrees in front of parliamentary select committees. Babbs describes his motivation for campaigning as coming from "a gut feeling that things could be better, politically, socially, and environmentally and that the reason they’re not is largely due to the conscious actions of powerful people rather than due to bad luck or any