Re: [DML] New DeLorean Parts (TAB's specifically)

["tmpintnl" <tobyp@xxxx>]

Marc - I appreciate your confusion in this matter. When I said that I 
checked the torque at every tech session, this was before I developed 
the new bolts. I still do a quick check in the area, but it's to 
verify that the installation is secure, not necessarily to retighten 
the bolts. For people who still have the OEM bolts installed, I 
believe that joint loosens from two primary causes - bolt stretch, and 
the wear that results to the washers and sleeves as the joint moves. 
A joint with proper clamp-up should never have rotational forces on 
the bolts or nuts that would overcome the installation torque. That 
means that, if the bolt is up to the task, the nut should never come 
loose. We use a self-locking nut just to be on the safe side. My 
concept of a torque check is to set the torque wrench at 50 ft-lbs, 
hold one end with a wrench, and check to see if the torque wrench 
clicks without rotation of the bolt or nut. My numbers suggest that 
the bolts can be stressed to near yield by torqueing to the high side 
of the range, and also by bending loads imparted by driving. The 
bolts that you referred to as being replaced after each use are 
actually designed to be torqued up to the elastic limit to maximize 
the preload on the bolt. The bolt has been taken to it's limit, and 
should therefore be replaced rather than being reused. The TAB's 
should never be loaded up to the elastic limit in a joint with severe 
bending loads, and a corrosive environment. My bolts never experience 
stresses even close to the elastic limit of the inconel 718. The OEM 
bolts are "moaning and groaning", while the TOBY-TAB's aren't even 
breaking a sweat. I hope that all of this rambling makes some sense 
to you.

>please do not take this as an attack on you or your project.

No problem. If I can't properly explain my design and analysis, then 
it's my problem for not efficiently and effectively communicating with 
the DeLorean community.

Toby Peterson VIN 2248
Winged1


--- In dmcnews@xxxx, "Marc A. Levy" <malevy@xxxx> wrote:
> Toby,
> 
> Your statement below confused me.
> 
> First you say you torque your bolts 2-3 times a year, and then you 
explain how the bolt stretches. Is it possible you stressed your bolt 
while re-torque so often?