songbird1959
New Member
Does anyone know the bolt torque setting for a chain plate. Size = 3 x 10mm thread bar welded to stainless chainplate.
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Chain plate bolt tensioning
- Thread starter songbird1959
- Start date
D
Deleted member 36384
Guest
If the stud is to pass through a wooden or GRP deck I would not worry about torque value. Make the backing plate very wide and tighten up firmly with a ring spanner or socket and wrench. Tighten all nuts in small steps sequentially, nipping up each one in stages of tension. After a sail, check them and nip up again if required. On my own boat I have an M20 nut holding an eyelet down for my rigging, I just make the nut up tight with a ring spanner, the rigging has not fallen down yet.
I am making a lot of assumptions here, care to describe what you are doing a bit more?
I am making a lot of assumptions here, care to describe what you are doing a bit more?
songbird1959
New Member
Re sealed a leak behind the chain plate, hence now re tensioning the bolts.
William_H
Well-Known Member
Bolts that are in tension ie pull to make it longer are more critical for tightening tension than those where the bolt is in shear. ie load is trying to slice the bolt in 2or 3.
In tension the bolt is actually stretched so that cyclic loads increse or decrese the stretch this will make the bolt more resistant to fatigue failure compared to a bolt where load stretches the bolt from no stretch to stretch. Typically this is in a cyclinder head bolt. here the material ie the head and block will not crush with tension of the bolt.
Now with your chain plate it is unlikely that your bolts are being stretched by the load. It is also unlikely that the material ie GRP will withstand the crushing force that would ensue if you did stetch the bolt corectly.
So you tighten up the bolt so that it will not come loose, be dislodged or allowed to cock at an angle so moving the load from shear to tension (on the nut). Mostly typical set spanner sets are sized (handle length) so that if you apply the most force you can on the spanner with one hand that will be a typical good tightness.(in a solid substrate) If there is a risk of crushing the substrate then you should go for less tension or a locking type nut (nylock) or similar which will stay in place even if not tight.
A said if hey are not very tight then keep a check on tightness at least after a bit of use. good luck olewill
In tension the bolt is actually stretched so that cyclic loads increse or decrese the stretch this will make the bolt more resistant to fatigue failure compared to a bolt where load stretches the bolt from no stretch to stretch. Typically this is in a cyclinder head bolt. here the material ie the head and block will not crush with tension of the bolt.
Now with your chain plate it is unlikely that your bolts are being stretched by the load. It is also unlikely that the material ie GRP will withstand the crushing force that would ensue if you did stetch the bolt corectly.
So you tighten up the bolt so that it will not come loose, be dislodged or allowed to cock at an angle so moving the load from shear to tension (on the nut). Mostly typical set spanner sets are sized (handle length) so that if you apply the most force you can on the spanner with one hand that will be a typical good tightness.(in a solid substrate) If there is a risk of crushing the substrate then you should go for less tension or a locking type nut (nylock) or similar which will stay in place even if not tight.
A said if hey are not very tight then keep a check on tightness at least after a bit of use. good luck olewill
songbird1959
New Member
Great, Thanks for the posts.
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