Prop Bolts
Moderators: John Dean, Moderator
The definitive text on all things nuts-and-bolts is usually regarded as, “An introduction to the design and behaviour of bolted joints” by John H Bickford.
At just shy of 1000 pages it’s not exactly light reading. Even in this book, the author regularly states that industry best-practice often remains the best guide and that exact science is not always available.
There is lots of surprising stuff, for example, how poor even calibrated torque wrenches are at setting bolt tensions. In the context of aircraft industry practice, the one really big surprise is the author’s view that locking-wire is really only any use to stop nuts and bolts falling out once they have become loose.
At just shy of 1000 pages it’s not exactly light reading. Even in this book, the author regularly states that industry best-practice often remains the best guide and that exact science is not always available.
There is lots of surprising stuff, for example, how poor even calibrated torque wrenches are at setting bolt tensions. In the context of aircraft industry practice, the one really big surprise is the author’s view that locking-wire is really only any use to stop nuts and bolts falling out once they have become loose.
I have to say I am not surprised by this.PB wrote:the one really big surprise is the author’s view that locking-wire is really only any use to stop nuts and bolts falling out once they have become loose.
I've never had any bolt ever come undone in service on any car or motorcycle I've ever owned. Often the cursing from the garage is because of bolts / screws that should come undone that don't!
I'll still be wirelocking my prop bolts though.
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.
If the good Lord had intended man to fly, He would have given him more money.
- Jonathan Wilkins
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- Joined: Wed Feb 06, 2008 9:55 pm
- Location: Ashford Kent
- Contact:
Hi guys, sorry for not replying to all your very useful advice. Actually just reading through your comments especially those of "PB" i feel much more in the picture and am realising that owning an aeroplane is quite an exciting learning curve.
As for the bolts........Robin Aircraft at Dijon have come to the rescue, having exactly the correct dimention 8.8 metric bolts which should be with me in a couple of days, thanks to our Robin experts here at Headcorn.
As for the bolts........Robin Aircraft at Dijon have come to the rescue, having exactly the correct dimention 8.8 metric bolts which should be with me in a couple of days, thanks to our Robin experts here at Headcorn.
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- Posts: 93
- Joined: Sat Jan 12, 2008 4:24 pm
- Location: Staffordshire
FWB Products Ltd of Whieldon Road, Stoke-on-Trent, ST4 4JE, have in stock almost any fixing you can think off, and they're cheap.
(Yesterday, I bought 8 Allen headed H-T bolts of 12.9DIN for £2.15!)
FWB's contact details: Tel : +44 (0)1782 744333 | Fax : +44 (0)1782 744577 | [email protected]
See also: http://home.jtan.com/~joe/KIAT/kiat_2.htm
(Yesterday, I bought 8 Allen headed H-T bolts of 12.9DIN for £2.15!)
FWB's contact details: Tel : +44 (0)1782 744333 | Fax : +44 (0)1782 744577 | [email protected]
See also: http://home.jtan.com/~joe/KIAT/kiat_2.htm
- Jonathan Wilkins
- Posts: 62
- Joined: Wed Feb 06, 2008 9:55 pm
- Location: Ashford Kent
- Contact:
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- Posts: 8
- Joined: Sun Jan 13, 2008 7:20 pm
Hello
For further reference and interesting background.
http://www.arp-bolts.com/Tech/Tech.html
Charlie
For further reference and interesting background.
http://www.arp-bolts.com/Tech/Tech.html
Charlie
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- Posts: 36
- Joined: Wed Jun 04, 2008 10:42 pm
- Location: hertfordshire
Just as an aside.You guys probably know this any way.As an apprentice I was tought that 1.5 threads should be showing through any nut,insert or fastening device in the aviation industry.1.5 thread general good practice.In the states they use 1 thread as stated in AC43.13-1B.
Have seen a fair few props fitted with the incorrect AN bolts.When a standard AN bolt is fitted the thread is about 1/8 inch below the end of the threaded insert on the prop boss(Lycoming engines).The correct length prop bolts have a longer thread and therefore protrud through the insert the correct amount.
Also have seen a few bolts with the only thing keeping them in postion is the wire locking.A couple of sump plugs to.Which was worrying.
Have seen a fair few props fitted with the incorrect AN bolts.When a standard AN bolt is fitted the thread is about 1/8 inch below the end of the threaded insert on the prop boss(Lycoming engines).The correct length prop bolts have a longer thread and therefore protrud through the insert the correct amount.
Also have seen a few bolts with the only thing keeping them in postion is the wire locking.A couple of sump plugs to.Which was worrying.