To: "SEAOC Newsletter" <seaint(--nospam--at)seaint.org>
Subject: Re: Loose Bolts with DTI Washers
From: Christopher Wright <chrisw(--nospam--at)skypoint.com>
Date: Sat, 3 Feb 01 13:38:31 -0600
> Are they +/- 10 percent or perhaps +/- 20 percent?
The NASA Fastener Design Manual says ±25% for a torque wrench; ±15% for turn of the nut; ±10% for load indicating washers and ±3-5% for fastener elongation measurement. The problem with a torque wrench in that the torque is mostly frictional torque and the coefficient of friction is never known very well.
In my end of the biz, split washers are considered about half as effective as a lick and a promise. Strictly cosmetic.
Christopher Wright P.E. |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com | this distance" (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)