Thursday 29 April 2021

The Lewis pin


Sorry in advance for the blurred photo. I really need to get a new phone.

Don't you love things which are as efficient as they are simple? This is a Lewis pin in action.

You drill a one inch hole into the top of the piece of stone, plug in a two piece Lewis pin and simply lift the heavy block from the top. The pin depends on the weight of the stone to become more efficient. The one inch diameter pin is split into two down the middle, and as the block is lifted the the two pieces are pulled in opposite directions by the rings on the ends, joined together at the top by a single ring through which you put the hook of the lifting gear. 

Using this bit of kit gives me so much pleasure.



30 comments:

  1. That is a very clever design. I went looking for the age of this design, and discovered that St Peter often appears in art with a set of these 'keys' at his waist.

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    1. Yes. That is a three pin Lewis. Slightly different method of cutting a wedge shape hole and feeding the pins in one by one.

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  2. ... but not as much pleasure as Lewis who first thought it up, made the first one and was the first to see it in operation.

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  3. I don’t know if I understood it correctly, but is it like those paper tube thingies that you can stick your fingers in, and the more you pull the more difficult it is to get your fingers back out?

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    1. I have added a photo of the pin withdrawn to give you a better idea.

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    2. Much bigger that I thought, but I guess it needs to be.

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    3. They come in all sizes, but my one ton one is - I think - the smallest.

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  4. I learn something new almost every single time I visit your blog. I would probably have gone my whole life without ever knowing about a Lewis pin were it not for you. Thank you for always being so interesting!

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  5. It actually looks a little work of art in itself Tom.

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  6. We are all learning so much from you, not sure how it works but does the Lewis pin expand.. Looking at the photo and the first thing that pattern on top of the stone reminds me of is the old church medieval sun dials.

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    1. There's a new photo which should explain how it works. Any marks made with a circle involved may look like old church inscriptions.

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  7. The pin sits only 1" in? I'd never known about this amazing tool! I can't think of any use for it about the casa right now but I do want one.

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    1. It's 1 inch in diameter, but about six inches in. See new photo.

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  8. I expect fitting it in the hole is tricky.

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  9. It is remarkable to think that the Lewis Pin that you use is made using a similar design to those used by the Romans.

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    1. They used three pin Lewis's I think. I may explain later.

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  10. The simplicity and great function makes the Lewis Pin (LP) a winner. Why can't more things be as well designed? Only here would I have ever learned about the LP. Fantastic.

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  11. This Lewis pin is tested for one ton. I have seen Lewis pins about three feet long for use on London Bridge which are tested for 25 tons. They work no matter how big or small.

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  12. I cannot say I ever saw this tool in my dad's collection, or my brother's. I do see how it works.

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  13. Freemasons (no, I ain't one)have often called their first sons "Lewis" in memory of the craft and as it compares to this vital tool, holding all in place beneath it.

    The stones of the old Roman bridge at Chesters, on Hadrian's Wall all have oblong slots for their Lewis pins which worked on the same principle as yours.

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    1. Yes. The three-pin Lewis has been around for thousands of years. Interesting about the Freemasons. My father was one but I am not called Lewis, obviously.

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