Fastener locking (again???)
Fastener locking (again???)
(OP)
I am competing the drawings on a panning base with a harmonic drive gearset. The device operates intermittently, so I do not have cooling problems and I can lubricate the thing with grease.
I intend to attach fasteners without threadlocker. I am not sure how well threadlocker operates around grease, and I have some delicate electronics components that will be dissolved by regular threadlockers. I have worked out my screw torques based on unlubricated threads. I want the screws all locked down as tight as possible.
One of the reasons I normally like to specify Loctite 242 and its equivalents is that these are lubricants, at least until they harden. I assume that the thread's behaviour under torque is more consistent than it would be unlubricated.
What would happen if I specified that the screw be greased before assembly? Grease is being used for the assembly anyway, so there is no problem with logistics. Obviously, a greased screw on its own, is more likely to come loose. On the other hand, the greased screw ought to be installed with a more consistent torque, and the high initial torque should prevent loosening.
Any thought?
JHG
I intend to attach fasteners without threadlocker. I am not sure how well threadlocker operates around grease, and I have some delicate electronics components that will be dissolved by regular threadlockers. I have worked out my screw torques based on unlubricated threads. I want the screws all locked down as tight as possible.
One of the reasons I normally like to specify Loctite 242 and its equivalents is that these are lubricants, at least until they harden. I assume that the thread's behaviour under torque is more consistent than it would be unlubricated.
What would happen if I specified that the screw be greased before assembly? Grease is being used for the assembly anyway, so there is no problem with logistics. Obviously, a greased screw on its own, is more likely to come loose. On the other hand, the greased screw ought to be installed with a more consistent torque, and the high initial torque should prevent loosening.
Any thought?
JHG





RE: Fastener locking (again???)
Have you considered either a Nylon patch or pellet in the fastener, or a pre-applied (dry) thread locking agent?
RE: Fastener locking (again???)
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Fastener locking (again???)
Can you use lock washers?
Tofflemire
RE: Fastener locking (again???)
All the literature I have been reading, including the messages in this forum, states that lockwashers make things come loose.
My parts are structurally rigid, and there is not a lot of room. If the parts are clamped solidly, there is no way anything can move.
My assembly strategy is to use as much tighening torque as possible.
JHG