Something I've been pondering for a while and wanted to see if I could get answers on this. On our cars and almost everything else, we want our bolts/nuts to stay in place
I can think of the following methods that are used to keep things in place:
1. Proper torque
2. Spring lock washers, or alternatively the "star" type washers
3. Castle nuts and cotter pins
4. Thread lock compound like the various flavors of Loctite
5. Lock tabs
6. Nylock nuts
Obviously some of these are situation dependent as to which holds best, but I'm wondering what is ideal:
A lot of critical engine bolts I'm familiar, rod caps in particular, but also head bolts/studs and others, seem to rely on only torque to hold them in place. This seems quite a reliable method, and I doubt that there's a fastener that's under more stress in a vehicle than the rod bolts.
Lock tabs seem sort of passé, but I do encounter them on older British stuff. I generally don't replace them, and instead go with something else depending on the application. I've been told that they really don't accomplish anything and will bend and deform to allow rotation if the fastener really wants to rotate.
Similarly, I've also been told that lock washers, which are still ubiquitous in a lot of applications, don't really accomplish anything either. Whether dealing with the traditional spring type or the star type, I can see that they won't accomplish a lot unless they can "dig in" to the mating surfaces, and I don't really see one doing that on the underside of a grade 8 bolt. Still, though, I keep them and always replace them with new when I remove an old one.
Loctite I know can be used in combination with the above, although I understand also that it can mess with proper torque(since as my little brain understands it, when a fastener is torqued you want it tight enough that fastener is under the correct amount of tension, but we can't easily measure that so torque is an easily measured stand-in value).
The places where I've used castle nuts it seems like ultimately you're really relying on the torque to hold it in place. Split pins are relatively weak, and if a nut in a high stress situation wanted to let go I'm wondering how the split pin would even be able to hold it. The split pin almost seems belt-and-suspenders.
When I've done suspension work, castle nuts are ubiquitous in many places. I've bought newer replacements where the part wasn't even drilled for a split pin, and Nylock nuts were supplied. The tie rod ends I have sitting in the garage now are that way. As I understand it, tapered joints such as you often find in suspension applications are designed to hold really without any fastener(as anyone who's ever worked on suspension knows, they don't come lose easily) and the bolt is just insurance. Nylock seems perfect for this since it just needs to avoid vibrating loose.
Do I have this summarized correctly? Are there situations where things like locktabs or lock washers would be considered appropriate?
I can think of the following methods that are used to keep things in place:
1. Proper torque
2. Spring lock washers, or alternatively the "star" type washers
3. Castle nuts and cotter pins
4. Thread lock compound like the various flavors of Loctite
5. Lock tabs
6. Nylock nuts
Obviously some of these are situation dependent as to which holds best, but I'm wondering what is ideal:
A lot of critical engine bolts I'm familiar, rod caps in particular, but also head bolts/studs and others, seem to rely on only torque to hold them in place. This seems quite a reliable method, and I doubt that there's a fastener that's under more stress in a vehicle than the rod bolts.
Lock tabs seem sort of passé, but I do encounter them on older British stuff. I generally don't replace them, and instead go with something else depending on the application. I've been told that they really don't accomplish anything and will bend and deform to allow rotation if the fastener really wants to rotate.
Similarly, I've also been told that lock washers, which are still ubiquitous in a lot of applications, don't really accomplish anything either. Whether dealing with the traditional spring type or the star type, I can see that they won't accomplish a lot unless they can "dig in" to the mating surfaces, and I don't really see one doing that on the underside of a grade 8 bolt. Still, though, I keep them and always replace them with new when I remove an old one.
Loctite I know can be used in combination with the above, although I understand also that it can mess with proper torque(since as my little brain understands it, when a fastener is torqued you want it tight enough that fastener is under the correct amount of tension, but we can't easily measure that so torque is an easily measured stand-in value).
The places where I've used castle nuts it seems like ultimately you're really relying on the torque to hold it in place. Split pins are relatively weak, and if a nut in a high stress situation wanted to let go I'm wondering how the split pin would even be able to hold it. The split pin almost seems belt-and-suspenders.
When I've done suspension work, castle nuts are ubiquitous in many places. I've bought newer replacements where the part wasn't even drilled for a split pin, and Nylock nuts were supplied. The tie rod ends I have sitting in the garage now are that way. As I understand it, tapered joints such as you often find in suspension applications are designed to hold really without any fastener(as anyone who's ever worked on suspension knows, they don't come lose easily) and the bolt is just insurance. Nylock seems perfect for this since it just needs to avoid vibrating loose.
Do I have this summarized correctly? Are there situations where things like locktabs or lock washers would be considered appropriate?
