Tightening bolts - any tips?

[KDOG]

Should I use a torque wrench? Or just tighten till there are tight but not too tight? I am worried about the rotor head cheek plate bolts, anything special about them?

[Aussie_Paul]

Use a torque wrench until you "know/feel" what is correct, This takes some time, There are more problems with people over tightening blots than under tightening!!!!!

A torque wrench is best.

Aussie Paul.:)

[KDOG]

What should the settings be?

[Vance]

Kevin, In my opinion you should always use a torque wrench. Over torque a fastener even once and it is damaged and will fail to perform it's task. Sometimes you can see the damage and sometimes you can't, it is still useless. If you undertorque a bolt and it still does it's job then it is heaver than it needs to be. I calibrate my torque wrench whith a weight on a regular basis. I personaly am not able tighten a fastner by feel any closer than plus or minus ten percent of my target. I also get a special feeling of doing it corectly when I corectly apply a torque wrench to each fastner. I find pleasure in this. I know many people who rarley use a torque wrench and they haven't killed anyone so you have to decide for yourself what your style will be.

There is more to corect torque than a torque wrench. A fastner is a strong spring and getting the corect tension on it is what is important. Thank You, Vance

[Vance]

Kevin, any good fastner suplier can give you a chart for maximum torque for a particular size and grade of fastner. Often a designer will specify a lesser torque to not crush or distort the things you are fastening together. Think, pay attention and allow yourself enough time to enjoy doing it corectly. After a thing has shaken for a while or gone threw heat cycles the fastners should be re-torqued. Thank You, Vance

[scottessex]

here is a nifty link to an FAA site about bolts, and it has torque specs.
http://www.faa.gov/avr/afs/300/pdf/2v-ch7_3.pdf

[Chuck Irby]

One more thing that I believe is good practice is to hold the bolt head and only turn the nut. I always use a flat washer at each end, and make sure the bolt is the proper length.

[scottessex]

You are right Chuck, a washer at each end is good practice, as is torqueing the nut and not the bolt.

[Dean_Dolph]

Scott, the link you provided is indeed a good one and shows a section out of the first book on my recommended list http://www.rotaryforum.com/forum/showthread.php?postid=29535#poststop

The book is a FAA Advisory Circular book and can be found here http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99C827DB9BAAC81B86256B4500596C4E?OpenDocument in PDF format.

This is a very useful book but downloading the stuff takes forever (very big book/chapters!) even with broadband so I bit the bullet and spent $20 +shipping so I can just grab it when needed. The link you show is out of Chapter 7 and pages 7-49 thru 7-74 of this chapter are particularly interesting. This section is hardware identification tables that show just about all of the hardware available with identification numbers and a description. If it isn't in here, we don't need it!

[scottessex]

I've still got all my A&P text books, Yes they are about worn out!
Good info to have.