Appropriate sizing of thimbles.

[smiling.shramana]

I am using 1/2" line for anchoring my old sailboat. I ordered 1/2" heavy duty thimbles for splicing an eye in the line assuming a 1/2" thimble goes with 1/2" line. The thimbles swallow the line. On spliced examples I've seen previously, the line sits a quarter of an inch or so above the lip of the thimble. On my new thimbles, the depth of the groove (where the line fits) is 1/2" so the line is flush with the lip of the thimble. Is this right? Is it because the thimble is a heavy duty one? What is the proper way to size a thimble to a line?
Thank you all for your help!!
Mike

[Matthew Sebring]

I've seen a gazillion different thimbles all sized to the same line or cable. I think the size is more a function of the manufacturer rather than anything else. As long as the thimble serves the job it's intended for (typically chafe protection) and is set up so that it wont accidentally pop out then you're set.

[smiling.shramana]

Matthew, Thanks for your reply. To simplify things. If a thimble is marked 1/2", would it be valid to assume that it was intended for 1/2" line?
Mike

[Matthew Sebring]

Yes, that would be a good indication. There's always a possibility that it could have been mis-made and mis-stamped but that's unlikely. The best indication is how well the line sets in the groove.

[smiling.shramana]

Thanks again for your input. I ordered both galvanized and stainless shackles (to match those that came on respective lines.) The parts ordered are rated heavy duty and came from a commercial fishing supplier, as opposed to a big box store. They are massive compared to the ones currently installed. They are all marked 1/2". These newer shackles would certainly protect the outer radius of the eye due to the line being more deeply set into the thimble.
Mike

[Ian McColgin]

Matt is right that you should look to how the line lies. If the U has a half inch inside diameter then all that's happened is the sides were run up past the more normal 1/2" (for this size) depth. It would give a bit more protection to the line and quite a bit more strength against flattening to the thimble.

G'luck

[smiling.shramana]

I spoke with someone from the supplier where I purchased the thimbles. He told me that it is common for manufacturers to use a smaller sized thimble (cheaper) which leaves more line exposed on the outside of the eye radius. The thimbles I purchased are heavy duty ones and are of the appropriate size. They are also US made and less costly than the ones from the big box store shipped from China.