Attach beam between two trees

[f91jsw]

This image shows the usual setup on adventure courses.

The platforms are clamped with pressure-treated beams and threaded rod. The wires are wrapped around pressure-treated blocks that distribute pressure against the trunk.

 

[altren]

I thought I'd revive this thread as I'm about to set up swings between two pine trees on the property, about 2.9m apart (but considering two pines that are 3.5m apart to fit three swings instead of two).

Here's what I'm considering, based on what's already been written:

95x95 pressure-treated timber
Attached to the pines with angle lashing using 6 mm natural fiber rope (as Totte_S suggested) https://www.k-rauta.se/produkt/rep-posamo-sisal-flatat-6mmx15m-naturfiber/4011645040135
Brackets for swing https://www.k-rauta.se/produkt/bygel-jabo-till-gungstallning/7393290033685

My considerations:
- It states that a 95x95 timber is mainly for posts since it's not strength-classified (e.g., C24), but maybe it's still suitable for the loads a swing beam is subjected to?
- Do you think a distance as long as 3.5 meters would work (would probably be a 4.8m timber)?
- Do you have any general opinions on what types of swings are good/less good? I'm thinking of https://www.k-rauta.se/produkt/gungsits-horby-bruk-plast-lime/7318890040413 and https://www.k-rauta.se/produkt/barngunga-horby-bruk-exklusiv-svart/7318890040215

I'll make sure to post pictures when it's done .

 

[KnockOnWood]

I think the following, based on what has already been written:
95x95 pressure-treated beam

I would have rather chosen a 45 x 120, and 45 x 95 is also sufficient.
And you can nail those up, or secure them with four large wood screws if you want something more solid.
The swings you show are fine if you want plastic things.
Good to have a safe swing for small children, so they can't fall out.

 

[altren]

Yes, I was also considering a 45x120 since the impact is mainly vertical, but I couldn't find a good mounting option for it - trapeze hooks were reportedly no longer approved for swings. Or are there versions that fit a 45x120?

I would prefer not to nail or screw into the tree, so I'll probably go with rope or tension straps.

 

[altren]

This is the result. Went with 45x120, works great. The lashing also seems to hold well (meaning no screws in the tree).

 

[ArneTW]

Keep an eye on the rope so it doesn't deteriorate from age/sun/water...

If the swing is to remain for a few years..

/ATW

 

[altren]

Keep an eye on the rope so it doesn't degrade from age/sun/water...

If the swing is going to stay for a few years..

/ATW

Yes, I plan to periodically pull down on the beam with full force and check the rope. Hopefully, it will hold up for a couple of years at least. I did the angle lashing according to the instruction earlier in the thread.

 

[juanxxx]

Altren, how did it go with the swing? I was thinking of doing something similar.

Which rope did you end up using and approximately how much was required for each lashing?

 

[altren]

So far, everything looks good. The plank has slipped down a few centimeters, which is likely due to the rope stretching a bit, but it still holds firmly. It seems to have survived the winter well.

In terms of strength, we've had two slightly larger children, approximately 30 kg each, swing as high as they can on each swing, and even though the plank flexes a bit, I've never felt worried that the construction wouldn't hold.

I bought two packages of the following rope, one for each lashing: https://www.k-rauta.se/produkt/rep-posamo-sisal-flatat-6mmx15m-naturfiber/4011645040135. It probably would have worked with a few meters of shorter rope, but it doesn't hurt to wrap a couple of extra rounds, I think.