Suspending a winch d-ring from ceiling

[Cpo1]

I recently attached a trailer tying ring (3 1/2" x 3 1/2" d-ring with loop pressed into the hardware mounting plate) from a roof truss in a storage unit. The ring is rated for 1000+ pounds. My purpose was a boat motor lifting system. It worked great with an attached block and tackle and was effortless. Since I attached the ring system vertically to a roof truss stud, the ring holding rating capacity may be lower since the weight is now suspended by two 3/8" lag bolts that are attached with a backup plate and compression on the 2 x 4. Can someone give me a reference for calculating the holding power of such a system? Thank you.

 

[CWatters]

Best I can manage is a reference that allows you to calculate the strength of the bolts..
https://www.boltdepot.com/fastener-information/materials-and-grades/bolt-grade-chart.aspx

I think the bolts are good for >1000 lbs but don't take my word for it.

I can't help with info on the roof truss and others will need more info, perhaps including the truss type, dimensions, existing loading, snow and wind loads?

 

[JBA]

See the below site for some information related to your issue

http://www.homepower.com/example-lag-screw-calculation

 

[berkeman]

I recently attached a trailer tying ring (3 1/2" x 3 1/2" d-ring with loop pressed into the hardware mounting plate) from a roof truss in a storage unit. The ring is rated for 1000+ pounds. My purpose was a boat motor lifting system. It worked great with an attached block and tackle and was effortless. Since I attached the ring system vertically to a roof truss stud, the ring holding rating capacity may be lower since the weight is now suspended by two 3/8" lag bolts that are attached with a backup plate and compression on the 2 x 4. Can someone give me a reference for calculating the holding power of such a system? Thank you.

Welcome to the PF.

Does the owner of the storage unit know you are doing this? You should consider just renting or buying a motor lift instead -- that would be much less risky. Thread is closed.

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