QUOTE(bdstone914 @ Aug 14 2020, 10:34 AM)
I am interested why you say lock washers are worthless. You are not a jackass. I respect your knowledge as an engineer.
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Very kind words
but I'm OK with being a jackass sometimes.
Best explained by NASA fastener design manual.
Click to view attachmenthttps://snebulos.mit.edu/projects/reference...ASA-RP-1228.pdfWithin automotive they are not used on modern cars for the follwing reasons:
1) They add huge variability to fastener torque and clamp load within the joint. Any critical joint is now secured by a DC nut-runner that usually monitors torque and angle within a narrowly defined set of upper and lower spec limits. Lockwashers just screw all that up. If the nutrunner doesn't achieve proper torque and angle the part or assembly is rejected into a repair area for root cause identification and/or rework. Repairs cost $ and degrade first time though process capability (i.e. thoughput).
2) They don't add any locking effect (per NASA) as confirmed in a multitude of automotive applications where they have been studied since I first came into the industry decades ago.
3) As a separate part, they are prone to being left out / forgotten. If a washer is required, captive washers are now the norm for error proofing reasons.
4) They sometimes fail (i.e. crack) and then vibrate out from under the fastener head - now you have a loose joint without any clamp load.
5) OEM's don't like to give away parts for "free" that perform no function
Paypal sent. Thanks for making these Bruce, I wasn't looking forward to making my own.
These are a great deal at $35 vs. my time to layout from scratch, cut, drill, etc.