Tensioning eye bolt/nut

[bsr]

Hi, I want to fix a swing to an angled tree branch. If I attach both ropes to the branch the swing twists. I understand I need to put something rigid in, so that the pivot point for both swing ropes is at the same height.

I thought the easiest way to do this was to fix through the branch using M10 threaded rod, penny washers and nyloc nuts on top, the rod extending below the bottom of the branch, with an eye nut or coupling nut and eye bolt at the bottom.

Any thoughts on this? I know you shouldn't use threaded rod in shear but M10 has a shear strength of 23kN so way above 1 person swinging. Total cantilever distance from the upper branch 30cm.

How do I ensure the bottom eye bolt/nut is properly fixed? I was thinking of eye nuts, but there's nothing to tension them against. How about eye bolts and coupling nuts, all fixed with loctite?

See picture. Thanks.

 

[Stivino]

What about using two nuts and lock them together? Or, one plain nut and a nyloc nut together?

 

[foxhole]

Knot the rope at same height below branch .

 

[bsr]

Foxhole, can you give a bit more detail? Just tying a knot in the rope isn't going to achieve anything, and knotting the two ropes together means I'll have a single pivot - I need two pivots to keep the swinging in a single plane.

 

[Burnerman]

It could be an idea to use four holes in the seat timber (two per side) and pass the ends of each rope through to triangulate?
John

 

[freddiemercurystwin]

Am I missing something obvious, why can't you just do this?

 

[Tigercubrider]

To be honest, drilling two whacking great holes in the branch worries me more.
You might be better getting some strops from Amazon and looping them over the branch a couple of times.

A couple of loops of string would let you evaluate the lengths.

 

[freddiemercurystwin]

Depends how big the branch is/type of tree etc!

 

[Tigercubrider]

I'm assuming that the sketch is reasonably to scale
It doesn't look more than 4-6 inches with two holes straight through 18" apart

 

[freddiemercurystwin]

You should never assume. You know what happens when you assume. You make an ass out of you and me.

 

[bsr]

The branch is 250mm diameter and there is about 300mm height difference.

FMT That is what I want to do. I can't get eye bolts long enough, longest I can find is, 200mm, hence looking at threaded rod and eye nuts.

 

[Stivino]

You could use cargo slings wrapped round the branch and looped through itself.

 

[freddiemercurystwin]

The branch is 250mm diameter and there is about 300mm height difference.

FMT That is what I want to do. I can't get eye bolts long enough, longest I can find is, 200mm, hence looking at threaded rod and eye nuts.

Ahh OK, you could join your threaded rod to your eyebolt with a threaded rod connector, I think I'd step up to M12 and grade 8.8 or above which might mean ordering from a more specialist supplier rather than toolstation or similar.

That said have you looked at swing equipment suppliers I can't imagine this has never been done before.

 

[lostinthelight]

When a lad we only ever used 1 rope with a dirty great mass of knots on the end and swung out over a 250 cliff drop into the river Wye,often with more than one person hanging on . Did one with 1 rope for the older grand kids but has the sophistication of a tyre for a seat/hang on

 

[lostinthelight]

Am I missing something obvious, why can't you just do this?

View attachment 189135

I would have thought the longer threaded side would be subject to some bending moment as well tension so would need to be thick enough to withstand it