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3:58 AM
What does the number 13 mean in 1/2"-13 Lifting Eye Nuts?
https://www.amazon.ca/dp/B0CPL14M6T?ref=ppx_yo2ov_dt_b_product_details&th=1
4:11 AM
13 TPI - the thread goes around the shank 13 times in one linear inch.
@User1974 So to drive the fastener one inch of travel, it will have to turn 13 times.
1/2" 13 is a common imperial thread, so it will fit a lot of 1/2" threaded posts.
If its really (REALLY) old then the thread might be 1/2" 12 but that's 50-100+ years ago.
You might also see 1/2"-20 which an imperial fine thread.
 
8 hours later…
12:36 PM
@Criggie Thanks!

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