RV-9A Wing Construction Log

Wednesday, June 16, 2004

Standard bolt practice

Mel Asberry was kind enough to drop me an email regarding my broken bolt and expressed some concern about it. I was also swapping some emails with builder friend Bill. We posed the question to Mel about the re-use of bolts that had been previously torqued. With his permission I post the following:

"It's ok to reuse bolts as long as they have not been OVER-torqued. Bolts need to be replaced only if there is any suspected problem.

Nylock nuts can be reused if the nut cannot be turned through the nylock by hand. Many people use a rule of thumb of reusing a nylock nut no more than 3 times depending on the application.

For example my prop uses nylock nuts and I will only reuse them once. (critical load)!"

Quote from AC 43.13-1b 7-40
"The importance of correct torque application cannot be overemphasized. Undertorque can result in unnecessary wear of nuts and bolts, as well as the parts they secure. Overtorque can cause failure of a bolt or nut from overstressing the threaded areas. Uneven or additional loads that are applied to the assembly may result in wear or premature failure."

The AC goes on with some suggestions, which I suggest you read. Chapter 7 of AC 43.13b

- posted by Matthew @ 11:05 AM