Lock washers with nylock type nuts?
Lock washers with nylock type nuts?
(OP)
Is there a general rule in using washers or lock washers with nylock type nuts?
In a structural, vibration enviroment?
Mating material is steel, fastener grade 8.
In a structural, vibration enviroment?
Mating material is steel, fastener grade 8.





RE: Lock washers with nylock type nuts?
Use nylock with flat washer.
RE: Lock washers with nylock type nuts?
Alternatives are:
1: A325 or A490 bolt/nut properly tightened
2: Double nutting to lock
3: Tack welding nut to bolt body
RE: Lock washers with nylock type nuts?
4. Wreck threads AOBE
RE: Lock washers with nylock type nuts?
TL
RE: Lock washers with nylock type nuts?
If it's pretensioned and normally in tension, then there should be little if any increase in axial stress. Mind you I'm speaking of high strength bolts (A325 & A490). Nylock nuts wouldn't apply.
Another alternative:
5. Load indicating washers
RE: Lock washers with nylock type nuts?
Thanks in advance for any help.
Tony Billeaud
Mechanical Engineer
Franks Casing Crew
RE: Lock washers with nylock type nuts?
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Lock washers with nylock type nuts?
It two 7/8" coarse thread bolts and they are torqued to 30 ft-lbs and 100 ft-lbs. That is the max torque that can be applied to the bolts.
Thanks,
Tony Billeaud
Mechanical Engineer
Franks Casing Crew
RE: Lock washers with nylock type nuts?
I would also like to add to the above - is there a rule of thumb for the minimum torque required to be applied to a nut in order to keep the nut from rotating on a bolt?
Thanks,
Tony Billeaud
Mechanical Engineer
Franks Casing Crew
RE: Lock washers with nylock type nuts?
Your torque appears to be about half what it should be. The rule of thumb is based on force, not torque. A fastener torqued so that the preload is about 50% to 100% of the yield stress should be adequate for most joints.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Lock washers with nylock type nuts?
To get the joint to stay together you need to apply a whole lot more torque to it.
The only other thing that I would suggest is trying high strength Locktite on the threads.
With the torque that you currently applying to the bolts you are only getting somewhere in the area of 7,000 pounds of clamp force. With that low force level you can get by with using unheat treated, grade 2 bolts.
RE: Lock washers with nylock type nuts?
To have a good SF we have chosen Gr 5 bolts for this application. The connection will be on a piece of equipment that will be transported on truck and by barge. I am limited to the 30 ft-lbs and 100 ft-lbs listed above and the nuts need to be removed after the transport is complete. Will a lock washer and 2 nuts work for this problem? If so, is locktite still required and will the nuts be removeable if locktite is used?
Thanks in advance for any and all help.
Tony Billeaud
Mechanical Engineer
Franks Casing Crew
RE: Lock washers with nylock type nuts?
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.