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I wanted to use a 4x6 for a beam for two swings, with eye bolts with washers through the whole beam vertically. However I do not have access to 4x6. I can buy two 2x6, but how would bolts work? Since bolts would be in between of two 2x6 I am thinking the holding capacity is not as high as through a 4x6 because of the gap between two boards.

Any thoughts on how to hang two swings on two sandwiched 2x6?

isherwood
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anm767
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  • Dry the lumber then glue it, for best performance. I would use 2-part epoxy with additives. However, drying lumber is very, very slow. – Harper - Reinstate Monica Feb 10 '22 at 06:47
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    Could also use chain to go around the 2x6s, and bolt the swing to the chain. – crip659 Feb 10 '22 at 14:05
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    "I do not have access to 4x6" Have you tried going to a lumber yard instead of the local big-box chain store? If they don't have one in stock, they'll cut one for you, probably while you wait. Might cost a bit more, but they can provide it kiln-dried if desired (it will be more stable that way), and can advise you about the strength of different species _and_ ways to protect it from the weather to get the best life out of it. What you may pay extra for the lumber is _more_ than made up for by the knowledge they'll share with you. – FreeMan Feb 10 '22 at 14:47
  • I did contact local lumber yards, they could not supply 4x6. It is not a common size here, or maybe it is too much a hassle for them, who knows. – anm767 Feb 10 '22 at 22:14

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Yes, you can, if you fasten them together well. The whole is greater than the sum of the parts, as they say, because stiffness and twist resistance are a matter of the cross-sectional aspect ratio. This would also result in a lamination, which is actually an improvement over a single timber because of the variation in grain and knots.

Use pairs of 2½" corrosion-resistant screws every 12-16", or use staggered, galvanized or stainless bolts at the same intervals.

isherwood
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  • I would agree 2 are stronger than one, knots in different locations and less twisting. Laminate and use a bolt that a washer can be on top this will provide full strength compared to screwing in a eye. – Ed Beal Feb 10 '22 at 21:06