Threadlock or Never-Seize

[mikehaugen]

Another method I like are serrated flange nuts, especially on aluminum

 

[Soundguy]

see them on lotsa rodnuts in old ford tractors..

I try to avoid them. :laughing:

But have tore down and rebuilt plenty of small block mopars and chevys.

As well as countless new 4 and 6 cylinders of various makes when I was on a big scrapping spree a few years back.

 

[Loadstar]

Large aluminum mill we work at does not use split washers due to spreading/loosening under high torque. I use blue loctite for vibrating machinery, antiseize marine grade for about everything else. If I am working on a fan typically the shaft bearings get retaining compound, the bearing mounting bolts/setscrews get blue loctite, and everything else is getting antiseize. Usually paint hubs and shafts with antiseize also because the weather, and RPMs can't shake it.

 

[sld]

Lock washers do work when used correctly but the only use I see in the aircraft industry is on ground studs. Nothing structural.

Just about every fastener on an aircraft has to be locking. The majority are from deformed threads in the nut. Proper torque also helps.

At home, I use a lot of Loctite. We will use that on experimental aircraft when safety wiring is not accessible. Never on production aircraft.

I like the nylon inserts on nuts and buy those from Harbor Freight all the time. In reality they are a one shot deal and should be tossed when removed.

 

[jeff9366]

I have been using Nord-Lock anti-vibration lock washers from Sweden the last year. So far, not one nut has loosened.

10 (5 Pair) 1" (25mm) Nord Lock Vibration Proof Lock Washer

Particularly good on the Disc Harrow. My Howse Disc Harrow has typical clamp adjustment and Nord-Locks make adjustment changes faster.

 

[Reverser]

As has been mentioned, threadlock is meant to hold the fastener tight in place. But AFAIK, never-seize is only meant to make the fastener easier to remove. I don't think part of its function is intended to lock the fastener in place. Although I don't know that for sure.

Also, head bolts and many other engine fasteners are fine threaded which are less prone to work loose, than are the ordinary, more coarse threaded fasteners.
And if I remember correctly, head bolts will stretch, which may aid in keeping the bolts tight after being torqued in a set bolt pattern. And since head bolts are stretched when tightened, they're supposed to be scrapped when removed. Although many times they're re-used.

Also, a nut can be removed much easier by hitting the exposed threads of the bolt with a small wire brush, before backing off the nut.

 

[hosspuller]

Just a caution. The published torque specs for bolts is based on oil lubricated threads. Anti-seize lubricates the threads better so one can over stretch the bolt without realizing it.

 

[Member]

YUP
Helical Spring Washers

Lock washers are good for those that sell lock washers.

Is a lock washer an effective torque retention device? - Mechanical engineering other topics FAQ - Eng-Tips

I like that! Thanks!

I use a lot of nylon insert lock nuts for my projects. The Navy seems to think they're good where they say "[...] self-locking inserts, [...] is preferable.". Any thoughts on that?

Edit: There's a book called something like Carroll Smith's Guide To Fasteners that I'd like to have but it's expensive to come by and rarely available used.

 

[Raspy]

I have always wondered if spring washers help.

The big lock washers used to hold the pintle eye on a interstate trailer sure gouge the nut when you take them aloose though. Seems like they provide some resistance to loosening.

Like these:

Excellent point.

A split washer type lock washer is designed to be more than just a spring. It is designed such that when it's "split", the cut becomes a cutting edge that cuts into the nut and the base that the nut is tightened against. Of course, this only works if the washer is made correctly. And if the base metal and the nut are both softer than the lock washer. Sometimes those washers can cut a lot of metal off resisting removal and that is what they are designed to do, resist removal. Star type lock washers can be very effective to as they are usually made of spring steel. But Locktight seems like the ultimate solution unless the fasteners are removed a lot, like I do with trailer balls.

 

[Deere Dude]

As has been mentioned, threadlock is meant to hold the fastener tight in place. But AFAIK, never-seize is only meant to make the fastener easier to remove. I don't think part of its function is intended to lock the fastener in place. Although I don't know that for sure.

Also, head bolts and many other engine fasteners are fine threaded which are less prone to work loose, than are the ordinary, more coarse threaded fasteners.
...
Also, a nut can be removed much easier by hitting the exposed threads of the bolt with a small wire brush, before backing off the nut.

I never thought of wire brushing my corroded bolts, but they were in a tough place to get at anyway. I just replaced my backing plate bolts yesterday and put Lok-Tite on and also a lock washer. Maybe it was overkill. I also put never-seize on the exposed portion of stud that sticks out for easy removal. More than likely that was a waste of time because in all likelihood I will never remove them again and if I do I will replace them anyway.
Great comments by the way. Thanks a lot.

 

[oldballs]

Just a caution. The published torque specs for bolts is based on oil lubricated threads. Anti-seize lubricates the threads better so one can over stretch the bolt without realizing it.

I thought bolt torque specs were based on dry threads, but I'm an amateur. Can someone set me straight.

 

[Diamondpilot]

I thought bolt torque specs were based on dry threads, but I'm an amateur. Can someone set me straight.

I always thought the same.

Dry for everything except aluminum that should have antisieze and critical engine parts that are oiled during assembly.

Chris

 

[mikehaugen]

I've seen charts that have both values... dry and lightly oiled.

 

[Oliver1655]

If using nylon insert locking nuts "nylock", you are to hand tighten them. The friction of using an impact gun or drill will potentially melt the nylon causing it to lose it's holding properties.

If you are needing a lock nut, you can tread a nut about 1/3 the way onto a bolt then tap the remaining portion of the nut with a hammer causing it to slightly deform/becoming slightly oval. You want it to require a wrench to tighten but not so tight you have to use excessive force to tighten it.

Have done this for years & have never had a failure.

 

[puckgrinder85]

We use top lock nuts (just a deformed nut) in everything except stainless.

 

[Raspy]

AFAIK, Engine assembly bolts should be torqued while lightly oiled. This would be head studs, rod bolts and the like, but lug nuts are dry. I put grease or anti seize on my lug nuts but have to be careful with the torque or they might snap.

You have to be careful with nuts on stainless too, because they have a tendency to gall if the threads are tight.

Also, don't use aluminum based anti-seize on stainless because aluminum and stainless react. So, anti-seize becomes seize. Use the copper based stuff or just straight grease. Never screw a stainless bolt into aluminum as a permanent fastener unless you use some kind of grease or teflon paste. No-lox electrical grease is great for this. Out in the weather, stainless screws can seize and strip the aluminum threads out when removed. This is the problem with boat hardware and outboard motors.