Joined: Feb 2012
Posts: 19,353
Likes: 5,471
From: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
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lock washers work by DIGGING INTO the contact surface... they can and do ruin aluminum parts they get smashed into" maddog34
Not completely correct. Lock washers also provide a spring like aspect to the fastener to handle the slight loosening that stresses and vibration produce in the installed bolt.
"Lock washers are special types of washers that prevent fastened parts such as nuts and bolts from loosening due to vibration and rotational forces12345. They provide a spring force or friction between the fastener and the assembled part, thereby maintaining tension and keeping the fastener tight." some quote from a online search so must be correct
Andy
I should have offered an answer for the OP's question- I do like to add flat washers (not locking ones) to my accessory fasteners when possible. Especially when the accessory is Al (and this is when maddog34 is correct) the flat washer reduces the wear on the accessory bolt hole's surface and makes tightening the bolt a bit easier to do. I have seen far too many split and star lock washers that are deformed, pried open or broken on the M5 and M5 bolts that most bikes use for these functions. What i dislike about thread locker is that so many people want to just forget about doing the periodic maintenance that keeps a well assembled bike working trouble free, and they believe thread lockers are the best "head in the sand" solution. Andy
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AndrewRStewart
Last edited by Andrew R Stewart; 05-17-25 at 07:47 AM.