Okay, here's a question on a little detail: In screwing a machine screw into a threaded piece of metal, what lock washer is most effective in assuring that the screw won't loosen: split ring or star? And if it's a star, would you recommend the ones with the star part going in or out or does it matter?
lock washers
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Split ring is for attaching parts, the external star is for attaching cable ends, such as ground cable to engine block and for attaching wire connectors to a fuse panel or electronic parts to a bracket. An internal would be for attaching a plastic cover to a box or similar. Your choice mainly depends on the metal to metal contact or lack thereof. You wouldn't want the star part to dig into plastic or soft material so you would use the internal star. You can use spray silicone before assembly to prevent moisture intrusion and is also good for cleaning grease off painted surfaces. Silicone doesn't attract dirt like other sprays.
What is the bolt holding? Is it compressing any fiberglass or plastic? OR is it just a bolt on an engine, like an alternator mounting bolt?
There's been other discussions about this recently. My thoughts on this is to use nylon lock nuts when holding anything to fiberglass, because the fiberglass compresses just a little and allows it to start loosening.
In an all metal application, I use split rings and the proper torque. When people say they have bolts shaking loose, I wonder if they were torqued properly.
OMG we have spell check!
There's been other discussions about this recently. My thoughts on this is to use nylon lock nuts when holding anything to fiberglass, because the fiberglass compresses just a little and allows it to start loosening.
In an all metal application, I use split rings and the proper torque. When people say they have bolts shaking loose, I wonder if they were torqued properly.
OMG we have spell check!
John: Depending on the exact application, Loctite is an excellent solution. There are different strengths too (Blue is probably the product of choice).
When I worked for Mallory Electric we would attach the distributor cams to a round shaft with Loctite and bake them in an oven. They NEVER came apart. Get the right product for the application and you should be good to go.
When I worked for Mallory Electric we would attach the distributor cams to a round shaft with Loctite and bake them in an oven. They NEVER came apart. Get the right product for the application and you should be good to go.
I put a halyard restrainer up at the top of my mast. I thought about loctite, but if I ever have to remove it, I'm not sure I'd want to have to use heat up there. I had to drill and tap the holes for the machine screws and I used split ring washers under the screw heads. From what people have written above, it sounds like that was the right washer. Thanks. (And, yes, I used Lanocote on the screws.)
John: The blue loctite can be removed with screw driver or wrench. No heat required.
Besides, there is nothing wrong with lock washer. Loctite just gives you another option.
Besides, there is nothing wrong with lock washer. Loctite just gives you another option.
John-from what I have seen on my boat, you would have been better off using the lowest strength loctite. The SS bolts that I took out of aluminum after being there 30 years were so incredibly corroded in place that most of them had to be cut out or just broke off. The loctite may keep the two different metals from contact and possible stop the corrosion caused by the two dissimilar metals.
I had my boom powder coated and I have been drilling, threading and shooting SS bolts into it. I am getting ready to install some lazy jacks. When I do I am going back and using loctite on all the SS just to try to keep the corrosion to a minimum.
Never Seez
There is a material called "Never Seez" you can use to help with the corrosion problems. You can get it in a tube or a little can. I believe it is made by Bostic.
There is another material called "Silver Goop" and one called "Blue Goop" (I am not making this up) that is used in aerospace applications to prevent corrosion. A whole line up of XXXXX Goop products is available. Swagelok is the manufacturer of this miracle stuff.
I recently read a report from the UK ministry of defense and another from NASA that split lockwashers are essentially useless since once they are flattened out they are just like a regular washer and don't provide any anti torque properties. Intuitively this is not obvious as you'd think there is a constant spring load on the sharp edges of the split since the washer is not being plasitcally deformed (only elastic deformation). But who am I to argue with NASA??
There is a material called "Never Seez" you can use to help with the corrosion problems. You can get it in a tube or a little can. I believe it is made by Bostic.
There is another material called "Silver Goop" and one called "Blue Goop" (I am not making this up) that is used in aerospace applications to prevent corrosion. A whole line up of XXXXX Goop products is available. Swagelok is the manufacturer of this miracle stuff.
I recently read a report from the UK ministry of defense and another from NASA that split lockwashers are essentially useless since once they are flattened out they are just like a regular washer and don't provide any anti torque properties. Intuitively this is not obvious as you'd think there is a constant spring load on the sharp edges of the split since the washer is not being plasitcally deformed (only elastic deformation). But who am I to argue with NASA??
I think a split washer may make some difference if you are not torquing the bolts enough. When you torque a bolt you ARE elastically deforming it.There is a material called "Never Seez" you can use to help with the corrosion problems. You can get it in a tube or a little can. I believe it is made by Bostic.
There is another material called "Silver Goop" and one called "Blue Goop" (I am not making this up) that is used in aerospace applications to prevent corrosion. A whole line up of XXXXX Goop products is available. Swagelok is the manufacturer of this miracle stuff.
I recently read a report from the UK ministry of defense and another from NASA that split lockwashers are essentially useless since once they are flattened out they are just like a regular washer and don't provide any anti torque properties. Intuitively this is not obvious as you'd think there is a constant spring load on the sharp edges of the split since the washer is not being plasitcally deformed (only elastic deformation). But who am I to argue with NASA??
Out of all the crazy contraptions I have built, the motorcycles, small engines mini bikes, go karts, weight equipment etc, the only bolts I have ever seen come loose were the ones that I hand tightened.
On my diesel in my boat, it has no lock washers on the connecting arm or the head bolts.
The only thing I have used lockwire on was a 25 mm cannon on a Bradley fighting vehicle. But that is some seriously repetative impact, and you don't want the receiver falling off into the turret floor while you are shooting at someone. lol
What are you guys having bolts come loose on?
Agreeing to argue
Not sure what we are arguing about? The split washer is elastically deformed, since when you remove the bolt the washer springs back to its' original shape. Thus it has a force component acting to drive the sharp corners of the split into the mating parts even when fully flattened out. So I am not sure why NASA is saying this is irrelevant?
When you torque a bolt you are elastically deforming it (stretching it) and this is what gives it the ability to resist loosening since the friction on the threads from the spring load is quite large as the torque increases. A thread acts like an inclined plane and for those that have split wood it is easy to see the force generated from an inclined plane from a hammer blow. We used to measure the elongation of bolts for propeller hub installations to make sure they were properly torqued. There is a gage called an extensometer for this purpose.
So I guess even if they do nothing I'll continue to use lock washers where appropriate, if they don't want to use them to go to the mars to save a few pounds I can understand why. As long as no one tells me they degrade the installation I can't go wrong, maybe.
Not sure what we are arguing about? The split washer is elastically deformed, since when you remove the bolt the washer springs back to its' original shape. Thus it has a force component acting to drive the sharp corners of the split into the mating parts even when fully flattened out. So I am not sure why NASA is saying this is irrelevant?
When you torque a bolt you are elastically deforming it (stretching it) and this is what gives it the ability to resist loosening since the friction on the threads from the spring load is quite large as the torque increases. A thread acts like an inclined plane and for those that have split wood it is easy to see the force generated from an inclined plane from a hammer blow. We used to measure the elongation of bolts for propeller hub installations to make sure they were properly torqued. There is a gage called an extensometer for this purpose.
So I guess even if they do nothing I'll continue to use lock washers where appropriate, if they don't want to use them to go to the mars to save a few pounds I can understand why. As long as no one tells me they degrade the installation I can't go wrong, maybe.
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