Chassis mounting harware ?

[patrick620]

Has anyone ever had a nut loosen up on them after securely tightened? I was wondering if I should use a TINY bit of thread lock. Nothing that would interfere with continuity and could be easily broken loose in the future if need be. Thanks.

[Thermioniclife]

A little blue thread lock is fine. I use nylock nuts when possible.

[Deke609]

Yeah, I think some kind of locking mechanism is a good idea. I've noticed that nuts/bolts connecting hardware to a chassis can loosen in surprisingly little time (months) if no star/lock-washer, locking nut or other "no-loosen" (e.g., threadlocker) method is used.  I suspect it's the repeated heating/cooling cycles.  I now use star washers that I buy in bags of 100 from McMaster Carr.  Cheap and effective.

cheers, Derek

[mcandmar]

Use metric hardware with proper threads

[Paul Birkeland]

Having serviced a ton of these kits over the years, I've had people ship me kits that were 30+ years old and all the hardware was still tight, but at the same time I've gotten freshly build but not working kits where all the hardware was loose.  I believe it's very unlikely to have hardware loosen on its own if it was well tightened to begin with.  Having said that, when I do factory builds for folks, I use nylon locking nuts on everything. 

[patrick620]

Metric hardware with proper threads? I would have to go buy a whole new set of tools, lol  Anyway... As a retired avionics tech that started with assembly and harness building, soldering 100 wire connectors, inspection, training, etc. I have seen plenty of nuts come loose even with lock washers. Mostly due to not being tightened properly to begin with. I am going to opt for letting the hardware "settle" and the check everything and then us a dab of Locktite before I start to wire it up.

Paul, If on factory builds or rebuilds you only use nylon locking nuts why are they not initially used as standard hardware in the kits?

[Doc B.]

Locktite is a PITA if you have to take something apart for a mod. Use the least strong formula - purple (222). BTW Locktite will wreak havoc on some RCA jack insulating washers. You can end up with a jack that spins, that you can't get apart because of the Locktite.

The issue really only seems to come to light when amps are shipped. It's important to go through the entire amp and snug up all the nuts and screws before packing it.

[patrick620]

Good advice, Doc. It is just second nature for me to recheck and recheck again for tightness before I move on. Much easier without wires in the way. I will never forget the ass chewin we got at Cessna from Dupont, a major customer. They spent a million bucks to find a loose screw w/ split ring lock washer that was never properly tightened on a push button circuit breaker board. Shipping/flying create vibration. Hot/cold. I have a bane for loose mechanical connections and cold solder joints.

[Doc B.]

We do the same on the race bike - "Click the torque wrench twice".