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[email protected] krw@notreal.com is offline
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Default Strength of a 1/2€? screw eye?

On Fri, 21 May 2021 11:28:14 -0400, J. Clarke
wrote:

On Fri, 21 May 2021 13:45:03 +0000, Seattlemusic
wrote:

I have four 1/2” screw eyes going into 2 x12s which are running perpendicular to 5x12 glulams holding up about 250 pounds total (hanging a cluster in a music studio). It seems rock solid but I have heard some say the break strength of ANY screw eye in wood of any type is 75 pounds. So yes technically it can hold it even with those

numbers but not nearly at the safety margin I want. I will be sitting under this cloud/cluster often.

Curious if this is sufficient or if I should open up the ceiling and get up higher with a through hole or something that won’t have a risk of wood + bolt failure.


Here's a calculator that might be helpful
https://www.engineeringtoolbox.com/wood-screws-allowable-withdrawal-load-d_1815.html

When I put in my hoists, I didn't trust screw eyes so added 2x8 beams
across the room, sitting on the walls to take the weight. My jousts
are "engineered" so can't take any suspended weight at all. The 2x6s
allow me to put a 2x across them and use an eye-bolt and washer.

Whatever you do, make sure the fastener is rated for *lifting*. Most
aren't.