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Torque Settings

Torque Settings

Torque Settings

Can anyone point me in the right direction to determine torque settings for aircraft bolts?  In particular, I am looking for torque settings for NAS6205 bolts.



RE: Torque Settings

I am not familiar with the specific fastener, and I can't seem to find my references that tell me about that fastener.  But, typcially the torque is based on the proof load of the fastener, around 80 to 90% of proof to be more specific.  The proof load depends on the material and grade of fastener.  There are several resources that give the tensile strength of particular grades of fasteners.  My favorite happens to be MIL-HDBK-5.

Otherwise, try some other convenient links:

A brief description on aircraft hardware when constructing on aircraft (kind of for the kit builder).



Hope this helps.  If not, I may be able to dig a little deeper and actually find the spec on NAS6205.


RE: Torque Settings

One thing you need to be aware of regarding the torque setting for any bolt is the application it is being used on: if a seal or gasket is being used, whether the bolt is being torqued with a nut or into an insert (and what the parent material is when an insert is used), etc.  All of these factors must be taken into account in determining the final torque on the bolt.

Most major aerospace companies have their own recommended torquing specifications giving details of general torques for specific applications and bolt diameters.  You could try contacting any local aerospace engineering companies in your area with details of your particular application.

Unfortunately, I'm not aware of any of these spec.s being freely available over the internet at present.


RE: Torque Settings

FAA Advisory Circular 43.13-1B provides a table of torque values for various bolt/nut combinations.

RE: Torque Settings

Torgue values depend on the things mentioned above, as well as the friction at the fastener/base material interface.  Certain materials (all of the Ti alloys come to mind) exhibit galling tendencies and require different lubrication during touqueing procedures that others.  For good, repeatable results, lubrication must be used for ALL torqueing operations.  Also, sometimes it is preferable to use a stud-nut joint instead of a bolt/screw-nut joint due to extreme difficulty in obtaining consistent values with certain types of fasteners and/or materials.  Often the best way to verify torque values is to measure stretch (although sometimes this is very difficult to do).  Repeated torqueing and relaxing of the fastener (4 or 5 cycles is enough) will go a long way toward repeatability and consistency.

See any high quality connecting rod manufacturese data on torqueing procedures for more info...

RE: Torque Settings

can anyone pls explain to me what do u mean by "torque to yield"? why shld anyone want to torque to the yield pt of the material??

RE: Torque Settings

The Former Douglas Aircraft Company (Now Boeing Long Beach) has an excellent handbook buried in the microfilm tapes that come with most of their Aircraft. This handbook is intended for the manufacturing/shop floor and gives many torque settings for different bolts in the installation environment where they will be used. This book is LARGE, so make sure you microfilm reader/printer has about a ream of paper in it. I consider this book one of the best overall assembly installation guides around. It is rarely used or read; too bad really.

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