A few years ago we put up a basic big-box wooden swingset for the young’un. He’s now 5 and has been asking for some monkey bars. We really don’t have the room, but then it occured to me that I might be able to get away with rings with mininmal effort + space. However, I have no idea what kind of beam I need for this. What’s everyone’s opinion in this? The grey lines are the existing swingset. 4×4 main supports with a doubled 2×6 span across the top that holds the swings. My thinking is that I’d use a 12′ 2×6 (if available and transportable in my car ;o) and attach the center to the existing frame with some metal connectors and the ends to 4×4 posts set in concrete. I’d then add a couple 2×4 angle braces between the new and old structure.
Alternatively, I might get two 2x6x8′ and join them together along 4′ (so it’d be a 12 bean with it doubled up in the middle for 4′.)
Anyways, any way to figure out if that’s enough for this type of load (a 43 lb 5 year old swinging back and forth).
Edited 4/24/2007 11:39 pm ET by darrel
Replies
Sounds like you've got a good plan. I respect you for getting involved in building safe equipment for your children and others who come to play there.
Considering that the existing support is very solid, I'd make the first aim to attach the new 2X6 to it very well. I'd suggest a double joist hanger and some stainless steel wood screws. Another method would be to drill out several of the holes in the joist hanger and use some 1/4" hex bolts to make the connection. I like your 2X4 braces. They should do a nice job of keeping that new beam from getting yanked around by the monkeys.
A single 2X6 beam is plenty strong if supported by 4X4s in concrete. You could hex bolt the 2X6 through the 4X4s to make a strong connection.
Hardware: It's advisable to add larger fender washers as well as lock washers when bolting up anything wooden which will be subject to unusual loads. They spread the load and allow for plenty of torque with the wrenches.
I suggested 1/4" hex bolts because I believe they're more than adequate but you might feel better with the next larger size. As with all advice from external sources, take it as something that needs your own inner stamp of approval and/or personal verification in practice before it's fully accepted.
Best Wishes, Peter
Edited 4/25/2007 5:11 am ET by Hudson Valley Carpenter
I would consider a double 2x6 with shallw grooves cut in the meeting faces of each board to slip the hanger bolts through. Add a large fender washer on top to sopread the load and keep the nut from pulling through.
a 43 lb 5 year old swinging back and forth
Don't forget two other loads: he will get heavier as he grows up, and at some point (where's my video camera?) dad will be on the the rings showing how to do back flips.
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Can't say how many hundred swingsets I built in my teens...you'll want to double up that new 2x6 and fasten them well together with screws top and bottom at 12" o.c. The torsional loads from a kid swing back and forth can be pretty high, and the doubled member will twist much less than the single. Either way you go, don't worry about things falling down. You have a good plan underway.
"The torsional loads"Ah! EXCELLENT point! Thanks for the advice everyone! With some luck I'll have it up this weekend and will post a picture...
I'll revise my advice to agree with Fast Eddie's method for hanging the monkey hardware. Sounds like Eddie may have some Tarzan in his geneology.
Edited 4/25/2007 9:53 am ET by Hudson Valley Carpenter
Nope. But it's easier to cut a shallow kerf on the face of two boards than it is to drill a hole through one."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
I'd do a 4x6 for the beam, and bevel the top so water drains off. With doubled 2x's, the rainwater stays a long time in the gap between the boards. The 4x6 is also perfectly mated to the 4x4 end posts, and there is standard hardware available to easily connect them together.
It is easier to drill the holes for the rings while the beam is still on the ground. And have fun, however you do your project!
Bill
This is great timing for me. I've been tasked to build a swing set for a 14-year old girl who has worn out her old one.12-foot span of 4x6 doug fir on 60-degree 4x4 a-frames 8 feet high, bolted to 8" poured piers 12" deep (no frost here) should handle the transverse loads of swinging, I think, but what sort of shear bracing do I need in-line with the main beam?BruceT
Bruce,Typically what I've seen done is to apply 4 knee braces running between the top beam and the A-frame members. These can be made from wood or from steel tubing with squashed ends to bolt through. The tubing is easier to do, and reliably strong both in tension and compression. Braces about 3' long ought to do the trick. Fastened at 45 degrees, they will connect to the beam and 4x4's about 25" from the intersection of the 3 elements at each end of the swingset. Much longer and adults hit their heads on the braces. Much shorter loses too much strength.Bill