Ny-Lock Nuts

[Pete]

I recieved the marsden nuts today that I plan on using on the rods and mains. What makes these a locking nut and what grade are they? I don't want to find out after there is a rod sticking through the block!

There is a small inner recess in the flat that bears on the part.
When tightened the flat distorts the body like a cone and pulls the
serrations in against the thread...When not tight there is no pressure on the threads. This is why you can spin them on and off by hand and can reuse them.
Most Marsden nuts are at least grade 8.
Fastener quality is not a good place to skimp.

Question: Ever wonder why the hot shot engine builders seldom use torque wrenches?
Answer: They use the bolt stretch method which uses a dial indicator to measure the stretch of the fastener. A plain high strength nut (no locking device) will never come loose tightened this way. Checked with a torque wrench they will usually be about 10% over the NORMAL torque wrench setting.