Volume 8 No 3 Jun 1957.pdf - Lakes Gliding Club

WRONGCORRECTNothreadin shearor bearingFig.2Simmonds nuts or Pinnacle nuts. These areself-locking nuts and they really are selflocking.They have none of the snags,of theabove methods and should be used wheneverpossible. One small point: make surethat the bolt thread does go right throughtbe Dut, otherwise the self-locking elementmay not be able to do its job. These nutsmay be used over and over again, but rejectany which do not seem to be reasonablytight on the thread. As a rough guide, ifyoucan screw the nut right on with your fingersit should be scrapped. Same manufacturersprefer to use slotted nuts and split pins incontrol circuits, etc., where there is a cha~of the bolt rotating, and you should alwaysuse the same method as the manufacturer.One method of locking which is sometimesseen should not be used an gliders.This is the practice of screwing down asecondnut tight onto the first one. It is anunreliable method and usually damages thebolt threads.W.hen. replacing bolts with new ones,make sure that the new bolt is the correctlength. Bolts should not be fitted with their-150-threads in shear or in bearing.. Fig. 2should make this clear.For this reason a washer should always befitted, and you should check that thestraight portion of the bolt does actuallyreach right through the fitting but notthrough the washer.Wing pins should be good fits in theirholes and should be kept greased. Theusual way of locking these is to fit safetypins, though ifa machine is only very rarelyderigged, it is a good plan to use split pinsand washers. These do not rattle so much,and are not so liable to catch on clothing,etc. This can be a danger with safety pins inexposed places, and it is quite easy to pullopen ~ safety pin unnoticed from this cause.Finally, a few general points, Never lIsea sIJlit pin more than once. Always use tilecorrect size ofsplit pin or safety pin. AlwaysuSe non-corrodible split pins. Do' replacelocking wire with new-if you have to unlocka turnbuckle. Do watch for corrosion, badfabric, slack fittings, hinges, faults in woodworkfinish, etc., and deal with thesematters at once.