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 multi-issue movement. It aims to empower UK citizens by providing easy ways for them to take action on the issues they care about, e.g., climate change, human rights and poverty. It claims "it’s 38 Degrees members who set priorities and we decide on what we campaign on together". They publish the results of their membership polls on their website. While 38 Degrees refers to 'members', there is no formal membership and these are simply people on its email mailing list. Each week 50,000 members, chosen at random, are asked to vote for their top priorities; only ones where there is