▁reduce ▁the ▁stress ▁on ▁so fter ▁materials ▁at ▁a ▁point ▁of ▁connection . ▁ ▁Some ▁linear ▁actu ators ▁use ▁a ▁kn uck le ▁thread ▁to ▁reduce ▁the ▁wear ▁of ▁the ▁steel ▁leads cre w ▁against ▁a ▁pl astic ▁sl iding ▁nut . ▁ ▁Fire f ight ing ▁resp ir ator ▁standard ▁EN ▁ 1 4 8 - 1 ▁" Res p ir atory ▁protect ive ▁devices ▁- ▁Thread s ▁for ▁face pie ces " ▁lists ▁a ▁kn uck le ▁thread ▁to ▁connect ▁metal ▁and ▁rub ber ▁parts . ▁ ▁The ▁rounded ▁cr est ▁and ▁root ▁of ▁kn uck le ▁threads ▁res emb les ▁the ▁Ed ison ▁sc rew ▁used ▁on ▁light ▁bul bs , ▁although ▁bul bs ▁have ▁a ▁much ▁shall ower ▁thread ▁angle ▁than ▁most ▁kn uck le ▁threads . ▁ ▁The ▁root ▁profile ▁of ▁kn uck le ▁threads ▁res emb les ▁a ▁ball ▁sc rew ▁thread , ▁although ▁the ▁fl ank ▁and ▁cr est ▁of ▁ball ▁sc rew ▁threads ▁is ▁often ▁trunc ated . ▁ ▁References ▁ ▁External ▁links ▁▁ ▁Kn uck le ▁thread ▁ ▁Category : Thread ing ▁( man ufact uring ) <0x0A> </s> ▁The ▁F ay ette ville - Man lius ▁Central ▁School ▁District ▁( F - M ) ▁is ▁a ▁K - 1 2 ▁public ▁school ▁district ▁located ▁in ▁the ▁Town ▁of ▁Man lius ▁in ▁Central ▁New ▁York , ▁en rolling ▁approximately ▁ 4 , 8 0 0 ▁students . ▁F - M ▁serves ▁a ▁large ▁portion ▁of ▁the ▁Town ▁of ▁Man lius , ▁including ▁the ▁villages