I've in the middle of building a play/swingset for my kids, and now I'm
second guessing the safety of my design. Since I don't have a huge
amount of space I modified a typical design I've seen around the
internet. First, I secured four 4x4's in the ground w/ cement to make
a 5'x5' "fort/platform" 5' off the ground. I have a 6"x6"x12' that I
plan to use for the swing beam off one side of the fort (I think a 6x6
should be okay for a 12' span from what I've read, if not correct me
here too please). I plan on bolting a 4x6 across 2 of the 4x4's to
support the swing beam. This next part is where I'm starting to worry
that I made a bad choice. Since I didn't want to take up a large
amount of space w/ the traditional A-frame, I put a 6"x6"x12' four feet
into the ground, secured w/ about 300lbs of cement. This gives me my
8' swing beam, which is what I wanted. So my question is, will the
6"x6"x12' that I will use instead of the traditional A-frame be strong
enough at the base to support the swinging? If not I guess I could add
some 4x4 supports, but that brings up the next question of how high and
what angle would I need to put them?


Thanks in advance for your input.

wrote:
So my question is, will the
6"x6"x12' that I will use instead of the traditional A-frame be strong
enough at the base to support the swinging? If not I guess I could add
some 4x4 supports, but that brings up the next question of how high and
what angle would I need to put them?

Sounds like a very solid design - I've seen (and played on, a while
ago) many that are far less sturdy than that, some that have/had been
up for many years. For example, the "play structure" that my father
built many years ago was a 6-7 foot high platform on 4x4 legs with a
2x4 frame for the plywood platform. It survived many years of abuse
from many neighborhood kids, and was only removed when we outgrew it.
I agree that the swinging motion on the single upright post might be
the weakest part, but in my non-expert opinion, a 6x6 sunk deep in the
ground with a bunch of cement should be fine, unless you regularly have
multiple large adults swinging "in phase" with each other. Smaller
kids, who will probably be swinging out of phase some of the time,
shouldn't be enough to stress a 6x6 too much. If it were me, I'd leave
it as is, keep an eye on it, and if it starts to show signs of wiggling
in the ground or cracking, then brace it up with 4x4's.
(Take this with a few grains of salt, of course...)
Good luck,
Andy

Wow, If a 2 X 2 is all that is needed to do the job, then a 4 X 4 is
better so lets use an 8 X 8.

I have lifted my car off of the ground with less than that. I have
lifted the front end of my car from a 2 X 12 which spanned 12 feet, with
a chain hoist. But then maybe I just take a lot of chances when I went
under it to work on it.

My house, which is a wood frame, sits on a sill which is an 8 X 10 and
spans 10 feet between foundation supports. That house is heavy enough
that when jacking up a section of it, that it broke my 5 ton jack, and I
had to go to a 20 ton jack. You see, that wood beam was supporting and
holding at least 5 tons or more of weight pushing down on it without
failing. Now do you really think that your swing and children will
really weigh even a half a ton of weight???

I am sure that there will be many out there that will disagree with me,
and that is Ok with me. But I personally think that you are into
overkill. With what you are building, I would not hesitate to put my
children on it, and all the rest of the kids in the neighborhood at the
same time.

But I tell you what, why don't you throw a rope over it and lift
yourself up and swing on that rope. you will know just as soon as you do
so if you can trust it to having your children on it.

Zap

wrote:
I've in the middle of building a play/swingset for my kids, and now I'm
second guessing the safety of my design. Since I don't have a huge
amount of space I modified a typical design I've seen around the
internet. First, I secured four 4x4's in the ground w/ cement to make
a 5'x5' "fort/platform" 5' off the ground. I have a 6"x6"x12' that I
plan to use for the swing beam off one side of the fort (I think a 6x6
should be okay for a 12' span from what I've read, if not correct me
here too please). I plan on bolting a 4x6 across 2 of the 4x4's to
support the swing beam. This next part is where I'm starting to worry
that I made a bad choice. Since I didn't want to take up a large
amount of space w/ the traditional A-frame, I put a 6"x6"x12' four feet
into the ground, secured w/ about 300lbs of cement. This gives me my
8' swing beam, which is what I wanted. So my question is, will the
6"x6"x12' that I will use instead of the traditional A-frame be strong
enough at the base to support the swinging? If not I guess I could add
some 4x4 supports, but that brings up the next question of how high and
what angle would I need to put them?


Thanks in advance for your input.

wrote:
I've in the middle of building a play/swingset for my kids, and now I'm
second guessing the safety of my design. Since I don't have a huge
amount of space I modified a typical design I've seen around the
internet. First, I secured four 4x4's in the ground w/ cement to make
a 5'x5' "fort/platform" 5' off the ground. I have a 6"x6"x12' that I
plan to use for the swing beam off one side of the fort (I think a 6x6
should be okay for a 12' span from what I've read, if not correct me
here too please). I plan on bolting a 4x6 across 2 of the 4x4's to
support the swing beam. This next part is where I'm starting to worry
that I made a bad choice. Since I didn't want to take up a large
amount of space w/ the traditional A-frame, I put a 6"x6"x12' four feet
into the ground, secured w/ about 300lbs of cement. This gives me my
8' swing beam, which is what I wanted. So my question is, will the
6"x6"x12' that I will use instead of the traditional A-frame be strong
enough at the base to support the swinging?

How obese are your children? You could swing a yearling elephant from
the rig you've described.

wrote:
I have a 6"x6"x12' that I
plan to use for the swing beam off one side of the fort (I think a 6x6
should be okay for a 12' span from what I've read, if not correct me
here too please). I plan on bolting a 4x6 across 2 of the 4x4's to
support the swing beam. This next part is where I'm starting to worry
that I made a bad choice. Since I didn't want to take up a large
amount of space w/ the traditional A-frame, I put a 6"x6"x12' four feet
into the ground, secured w/ about 300lbs of cement. This gives me my
8' swing beam, which is what I wanted. So my question is, will the
6"x6"x12' that I will use instead of the traditional A-frame be strong
enough at the base to support the swinging?

Thanks in advance for your input.

I'll not be as slanderous as others in answering your question. I too
wish to protect my children from the things I "think" I build
correctly.

I built my boys a swing/fort a couple of years back. I used a 4X6 for
the beam and a 4X6 for the post. I've had several kids (and adults)
play on this structure and never once felt one was going to get hurt
(at least not from the structure failing). You could save some money by
returning the 6X6's and use 4X6's without losing sleep at night. But,
if you've already purchased the material and dont want to make the trip
back to the store, use them and don't worry, they are plenty strong.

JD

300 lbs of cement? four feet into the ground, hell why not just use
telephone poles? While your at it get a well drilling rig and really sink
them in the ground! My son's swing set is red cedar 3" timbers and 1X4's and
all that sits ON THE GROUND with a couple of stakes hammered in. The only
thing that is cemented is the pole for the slide and I only used a 1/2 bag
of cement for that. What you've got is the frame work for a nuclear blast
proof set!

My set cost 700.00 and took me a day and used about 15x6 ft of land!

I think what we've got here is a troll..

Searcher

I think the only real concern would be the lateral forces on the dsingle
upright leg when big folks are swinging in synch.. I'd get a couple of
adults (one for each swing you have), and get them all swinging together (in
phase). Have someone stand by the side, and see how much the leg deflects.

Make your decision based on that.

empiracle evidence is always best....

-_JD


wrote in message
oups.com...
I've in the middle of building a play/swingset for my kids, and now I'm
second guessing the safety of my design. Since I don't have a huge
amount of space I modified a typical design I've seen around the
internet. First, I secured four 4x4's in the ground w/ cement to make
a 5'x5' "fort/platform" 5' off the ground. I have a 6"x6"x12' that I
plan to use for the swing beam off one side of the fort (I think a 6x6
should be okay for a 12' span from what I've read, if not correct me
here too please). I plan on bolting a 4x6 across 2 of the 4x4's to
support the swing beam. This next part is where I'm starting to worry
that I made a bad choice. Since I didn't want to take up a large
amount of space w/ the traditional A-frame, I put a 6"x6"x12' four feet
into the ground, secured w/ about 300lbs of cement. This gives me my
8' swing beam, which is what I wanted. So my question is, will the
6"x6"x12' that I will use instead of the traditional A-frame be strong
enough at the base to support the swinging? If not I guess I could add
some 4x4 supports, but that brings up the next question of how high and
what angle would I need to put them?


Thanks in advance for your input.

Well I must say, my wife and I did laugh at some of the responses, but
honestly I'm not just trolling the boards or looking to lob a softball
for someone to practice their funnies.

There's going to be 3 swings, and at times, could have an adult or two
along w/ a child. JD summed up my concerns best

"the lateral forces on the dsingle upright leg when big folks are
swinging."


With big folks being 140-200lb adults swinging, I just was unsure of
how much force would be generated on the single upright leg.




jd wrote:
I think the only real concern would be the lateral forces on the dsingle
upright leg when big folks are swinging in synch.. I'd get a couple of
adults (one for each swing you have), and get them all swinging together (in
phase). Have someone stand by the side, and see how much the leg deflects.

Make your decision based on that.

empiracle evidence is always best....

-_JD

wrote in message
oups.com...
Well I must say, my wife and I did laugh at some of the responses, but
honestly I'm not just trolling the boards or looking to lob a softball
for someone to practice their funnies.

There's going to be 3 swings, and at times, could have an adult or two
along w/ a child. JD summed up my concerns best

"the lateral forces on the dsingle upright leg when big folks are
swinging."


With big folks being 140-200lb adults swinging, I just was unsure of
how much force would be generated on the single upright leg.


Acceleration would be one G, so you can use the weight and standard angular
momentum calculations for the radius of the swing. Not that it makes a lot
of difference unless you're going to compute the length and leverage of the
elastic upright.

wrote:
Well I must say, my wife and I did laugh at some of the responses, but
honestly I'm not just trolling the boards or looking to lob a softball
for someone to practice their funnies.

There's going to be 3 swings, and at times, could have an adult or two
along w/ a child. JD summed up my concerns best

"the lateral forces on the dsingle upright leg when big folks are
swinging."


With big folks being 140-200lb adults swinging, I just was unsure of
how much force would be generated on the single upright leg.




jd wrote:
I think the only real concern would be the lateral forces on the dsingle
upright leg when big folks are swinging in synch.. I'd get a couple of
adults (one for each swing you have), and get them all swinging together (in
phase). Have someone stand by the side, and see how much the leg deflects.

Make your decision based on that.

empiracle evidence is always best....

-_JD




It seems some people are misunderstanding your concern. You will have
ZERO issues with downward weight. You ropes or chains will break before
the beam or post would You concern is the lateral (side to side) force.
Will it start moving back and forth when someone is swinging. It could
be a 12x12 post and still come crashing down if enough side force is
applied.

At my campground there is a baby/toddler swing set made of two 4x4
posts, set in concrete to an unknown depth. with a 4x4 cross member on
top. The swings, although designed for little kids, do attract some big
kids too. It is holding up OK and not moving. I think you will be fine.

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wrote in
oups.com:

Yep you are correct, the only thing I am concerned with is the single
upright 6x6 post that's being used in lieu of the traditional A-frame.
I don't know how to do the calculations, but if you have 200-400
hundred pounds of people swinging in phase on a 5 1/2 foot chain, it's
going to be a lot more than just that few hundred pounds of force at
the base of that upright post. I don't have much experience w/
building things like this and wasn't sure if the post could easily
shake loose or crack the concrete from the swinging. It's reassuring
to hear the 4x4 swing at your campground hasn't moved even when bigger
kids have played on it, thanks for the info.








It seems some people are misunderstanding your concern. You will have
ZERO issues with downward weight. You ropes or chains will break
before the beam or post would You concern is the lateral (side to
side) force. Will it start moving back and forth when someone is
swinging. It could be a 12x12 post and still come crashing down if
enough side force is applied.

At my campground there is a baby/toddler swing set made of two 4x4
posts, set in concrete to an unknown depth. with a 4x4 cross member
on top. The swings, although designed for little kids, do attract
some big kids too. It is holding up OK and not moving. I think you
will be fine.

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http://www.x-privat.org/join.php


I have a yard swing out back made from landscape timbers and it has been
with us for 20+ years now. In its time it has seen well over 400 pounds
of various and sundry sized urchins abusing it and hasn't given out on us
yet.