OT: teatime teaser - a what's this riddle :)

[DCL_dave]

Does it lock itself, lift stone weight, and even open the pearly gate?

https://ibb.co/wY75WVv

[stevef]

I seem to remember that the Romans used a similar system to lift stone blocks and it's called a Lewis.
The separate parts are inserted into a pyramid shaped hole and the ring lifted. The parts are not able to exit the smaller hole all at the same time.
Hope that makes sense!
Regards
Steve

[DCL_dave]

You are correct, Steve, well done

This type is called a 3 legged Lewis, or 3 pin Lewis, also nicknamed sT Peter's Keys...it's a lovely old iron thing anyway

[Lakey]

I seem to remember that the Romans used a similar system to lift stone blocks and it's called a Lewis.
The separate parts are inserted into a pyramid shaped hole and the ring lifted. The parts are not able to exit the smaller hole all at the same time.
Hope that makes sense!
Regards
Steve

Very ingenious. Someone was on their "A game" when they invented that gadget.

Lakey

[stevef]

Thank you!
I can claim no real credit; I read an explanation in a book written by a metal detectorist searching in the north east, he used to find large dressed stones in the river with strange shaped holes cut into them.
A nice piece of forge work!

[DCL_dave]

I worked for 2 years in a quarry on Portland when I first left school, and can remember seeing bigger sets that this in our quarry gear but I can't remember us ever actually using them in the time I was there...we picked 'nip holes' in the ends of the stones and used a simple device called 'nips' or a chain dog - big iron dogs on rings with a long chain through them.

[torrens]

Hi Dave,
we were shown 2-pin Lewis use at Weymouth School of Masonry 30 years ago but I don't remember seeing any used anywhere I worked. I suppose it's ancient technology that's been overtaken by big hydraulic stuff.

I have had some exercise with manual block and tackle hoists though..... still handy on site.

[DCL_dave]

Hi Dave,
we were shown 2-pin Lewis use at Weymouth School of Masonry 30 years ago but I don't remember seeing any used anywhere I worked. I suppose it's ancient technology that's been overtaken by big hydraulic stuff.

I have had some exercise with manual block and tackle hoists though..... still handy on site.

Hi ya,


Funnily enough, I was talking to a nice chap earlier on today about the old mason school at the Weymouth college site in Newstead road (now sadly gone) He had travelled down form London to buy some masonry tools I had for sale, turns out he attended there about 20 odd years ago, I attended there about 35 years ago, small world really.


Re. ancient technology, those old boys knew what they were doing.

[w preston]

50 years as a stonemason (retired now) used them many times. different sizes for all size weights. nickname in Yorkshire is dogs.

[DCL_dave]

50 years as a stonemason (retired now) used them many times. different sizes for all size weights. nickname in Yorkshire is dogs.

Hi,

Did you ever use the 3 legged lewis?...or the more modern 2 pin/split pin lewis, or similar but older designed chain lewis? (there does seem to be a few different types of lewis)

I think dogs may be a fairly generic term for any lifting apparatus that bites onto the stone?...As I said before we used a similar type to those shown in this pic:

https://quarriesandbeyond.org/articl...fting_dog.html

[w preston]

w e used 2 and 3 pin straps and the plate that uses atmospheric pressure run by a generator, when lifting above oneself was always listening for the geny to stall and the load would come down?, them Honda generators are one hell of a machine thank god.

[DCL_dave]

w e used 2 and 3 pin straps and the plate that uses atmospheric pressure run by a generator, when lifting above oneself was always listening for the geny to stall and the load would come down?, them Honda generators are one hell of a machine thank god.

Hi ya,

Thanks for the info. I must admit that I have never heard of the atmospheric pressure plate?...did some searching and found a system that uses a vacuum plate (Stone Magnet is one type?...) sounds a bit hairy at any rate!

Have seen the chain dogs slip once or twice when heaving a big stone out of the bed and on to the bank...now that does make you jump a bit

[w preston]

yes vacuum plate we used sponge the stone with water to make a airtight seal then lift with machines or block and tackle Honda generator would power the vacuum 14lb per sq inch. when lifting ashlar stone would use raw bolts for lifting then remove when in position and place dowel in the hole for the next stone.its nice to be retired now?