Advice on size of wood

[mullermn]

Hi,

I'm planning to make some swings for the kids, but I'm having trouble deciding what dimension wood I should use to ensure that they're strong enough - and obviously whatever I settle on has to be available from a yard where I can get hold of it, and available in lengths long enough to make the project.

The largely arbitrarily-arrived-at design I've got in mind would entail a 3m span for the top bar (not entirely unsupported, as I plan to have diagonal supports at the hips) at a height of 3m off the ground (so legs about 3.4m long).

So far the best option I've come up with is 100m, square profile treated softwood posts from these guys: 3.6m x 100mm x 100mm treated softwood post . They're local to me and sell that specification of timber in 3.6m lengths, which would give me all the lengths I need.

Any advice gratefully received.. as I always find with woodworking projects, if somebody handed me a pile of all the right bits and said 'build it' I'd be fine, but add in the infinite diversity of materials that are available and I get lost in a maze of alternatives...

Cheers

 

[Droogs]

I remember a thread about the same thng a couple of years ago. have a look in the much improved search facility

 

[Yojevol]

Having lived through 3 generations of swing users, me, my daughters and most recently, my grandchildren, I don't think there is anything amiss with your proposal. I assume the supports will be A-frames. Make sure the diagonals are big enough to stop the whole structure from racking.
The proposed timber is treated, which is good, but the most likely onset of rot will be at ground level. However this is unlikely to be a problem as kids grow up so quickly these days they'll be into new interests in a blink of the eye.
Enjoy it while it lasts.
Brian