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Explanation of Types

Type Description Examples
Flush Bracket These are rectangular metal plates affixed to triangulation pillars, walls, buildings etc. If they are not affixed to a triangulation pillar they are often referred to as Non-Pillar Flush Brackets (NPFB). They are about 6" x 3" in size and the location of most of them is known through Ordnance Survey (OS) records. Each Flush Bracket (FB) has a unique serial number which makes them highly 'collectable' and there are several numbering types.  
  One to four figure number
The earliest FBs you can find and date from 1912-1921. Numbered from 1-3000. A few can be found on triangulation pillars.
Introduced in the 1920s these are found on pillars and as NPFBs. There are two sub-types, S below the number and S left of the number.
First appeared in 1936. Unlike S-series brackets numbers below 1000 do not have leading zeroes. Used extensively in Scotland and never found on triangulation pillars.
Just sixteen brackets used in London in the early 1930s.
  Five figure number
These are effectively S-series brackets above S9999 where they ran out of room for the S (S-below was discontinued as the S interfered with the measuring equipment).
Projecting Bracket An early type of metal bracket used for a short time before the introduction of flush brackets. They are all the same and have no unique attributes. Reading, Greyfriar's Church
OSBM Bolt Used alongside the G-series of flush brackets these are placed where there wasn't a convenient building or wall to provide a vertical surface on which to affix a flush bracket. They are domed metal bolts about 1" (50-60mm) in diameter fixed to horizontal surfaces engraved with OSBM and the benchmark symbol. Caban Coch Dam
Cut Bench Mark By far the most common type. Used and made from the 1800s to around 20 years ago. You won't have to walk (or drive) very far in any village, town or city in Britain before you spot one of these. Chiseled into stone, brick or wood on all sorts of vertical structures. A familiar horizontal levelling line with a three line arrow pointing towards it (usually upwards). Each one is unique depending on the mason who cut it, some are plain, some decorated. Some roughly cut, some exquisitely cut with high accuracy. Some small, some huge. Wallingford, 60 High Street
Cut Bench Mark with Bolt Old and rare these have a metal bolt screwed either alongside the horizontal cut of a cut bench mark or at the point of the cut arrowhead. Usually has what appears as a screwhead horizontal in the head of the bolt. These are highly prized by benchmarkers. Dorchester Abbey
Rivet Usually found on horizontal surfaces these are cut marks with a small metal domed brass rivet at the apex of the cut arrowhead marks. Swyncombe, Icknield Field
Pivot Fairly rare these are used on horizontal surfaces such as soft sandstone, where the insertion of a rivet would break away the stone. They consist of a small hole or depression cut to take a pivot, a steel ball bearing of 5/8" diameter (16mm). In use, the pivot is placed in the depression and the levelling staff held on top of the pivot. Sutton Bridge
Fundamental Bench Mark These are the key to the whole levelling of the UK. Granite blocks with large domed metal caps. Just like an iceberg this is just the tip of a fairly extensive underground structure. Highly accurate height stations still used today as the baseline to levelling. Conwy
Triangulation Pillar Familiar to anyone who walks in the British countryside, these can often (but not always) be found at hilltops. Most have a flush bracket affixed to one side. Huntingland

Triangulation Pillar

Triangulation PillarHinksey Halt Footbridge
Triangulation Pillar2987 - White Horse Hill
Triangulation PillarS1522 - Cutsdean Hill
Triangulation PillarS1627 - Great Ormes Head
Triangulation PillarS1633 - Holyhead
Triangulation PillarS1652 - Barton Stacey
Triangulation PillarS1693 - Fullerton
Triangulation PillarS1834 - Beachy Head
Triangulation PillarS1854 - Clare Hill
Triangulation PillarS1892 - Britwell Hill
Triangulation PillarS1984 - Chalk Farm
Triangulation PillarS2025 - Shirburn Hill
Triangulation PillarS2141 - Massingham
Triangulation PillarS2414 - Waden Hill
Triangulation PillarS2477 - Stoke Hill
Triangulation PillarS2479 - Mount Joy
Triangulation PillarS2517 - Wroxall Down
Triangulation PillarS2521 - St Catherines Hill
Triangulation PillarS2526 - East Garston
Triangulation PillarS2532 - Matcham Park
Triangulation PillarS2590 - Pentridge Hill
Triangulation PillarS2716 - Lyndhurst
Triangulation PillarS3006 - Calton Hill
Triangulation PillarS3121 - Oswestry Station
Triangulation PillarS3147 - Lickey Hill
Triangulation PillarS3545 - Black Pill
Triangulation PillarS3569 - Hips Heugh
Triangulation PillarS3689 - Night Fold Field
Triangulation PillarS3697 - Ross Castle
Triangulation PillarS3700 - Hurst Hill
Triangulation PillarS3738 - Blewburton Hill
Triangulation PillarS3763 - Huntingland
Triangulation PillarS3874 - Fox Hatch
Triangulation PillarS3986 - Wilmington Hill
Triangulation PillarS4365 - Gog Magog
Triangulation PillarS4472 - Hertford Heath
Triangulation PillarS4511 - Waddesdon Hill
Triangulation PillarS4667 - Down Hill
Triangulation PillarS4734 - Fitty Hill
Triangulation PillarS4781 - Dunnet Head
Triangulation PillarS4909 - Nuffield
Triangulation PillarS5074 - Coton
Triangulation PillarS5279 - Beeston Hill
Triangulation PillarS5293 - Battle Hill
Triangulation PillarS5529 - The Begwns
Triangulation PillarS5540 - Brightwell Barrow
Triangulation PillarS5724 - Lowbury Hill
Triangulation PillarS5725 - Farnborough
Triangulation PillarS5727 - Compton
Triangulation PillarS5726 - Lough Down
Triangulation PillarS5729 - Grims Ditch
Triangulation PillarS5730 - Pit Plantation
Triangulation PillarS5731 - White Hill
Triangulation PillarS5796 - Penrallt-Y-Gardde
Triangulation PillarS5798 - Kings Bush
Triangulation PillarS5826 - Fore Down
Triangulation PillarS5828 - Steventon Hill
Triangulation PillarS5882 - Rogues Lane
Triangulation PillarS5907 - Crafts Hill
Triangulation PillarS5952 - Sutton
Triangulation PillarS6076 - Woolsbarrow Camp
Triangulation PillarS6168 - Greenmoor Hill
Triangulation PillarS6185 - Birch Heath
Triangulation PillarS6207 - Monument Hill
Triangulation PillarS6244 - Hill Farm Winchelsea
Triangulation PillarS6280 - Wroughton
Triangulation PillarS6489 - Winshields
Triangulation PillarS6678 - Duncansby Head
Triangulation PillarS6764 - West Farm
Triangulation PillarS6778 - Great Tew
Triangulation PillarS6936 - Greenham
Triangulation PillarS7157 - Broom Farm
Triangulation PillarS7198 - Horton
Triangulation PillarS7216 - Twt Hill
Triangulation PillarS7288 - Herstmonceux
Triangulation PillarS7294 - Hermon
Triangulation PillarS7305 - Parys Mountain
Triangulation PillarS7307 - Pendefig
Triangulation PillarS7324 - Mynydd Bodafon
Triangulation PillarS7328 - Aberffraw
Triangulation PillarS7330 - Bryn Euryn
Triangulation PillarS7542 - Castle Rising
Triangulation PillarS8068 - High Bridge Farm
Triangulation PillarS8142 - Lands End
Triangulation PillarS8635 - Oakington
Triangulation PillarS9325 - Breck
Triangulation PillarS9369 - Monk Field
Triangulation Pillar10639 - Noup Head
Triangulation Pillar10640 - Mull Head
Triangulation Pillar10644 - Whitelet
Triangulation Pillar10646 - Langskaill
Triangulation Pillar10677 - Wideford Hill
Triangulation Pillar10738 - Dunwich Common
Triangulation Pillar10814 - Gayfield
Triangulation Pillar10850 - Glimps Holm
Triangulation Pillar11155 - Littlebury Hedge
Triangulation Pillar11492 - Transit Meridian
Triangulation Pillar11666 - Solar
Triangulation Pillar11798 - Inkpen


All the bench marks I have logged. See my profile on the Bench Mark Database.

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Explanation of Types
Flush BracketFlush Bracket(247)
Projecting BracketProjecting Bracket(6)
OSBM BoltOSBM Bolt(16)
Cut Bench MarkCut Bench Mark(1987)
Cut Bench Mark with BoltCut Bench Mark with Bolt(134)
Fundamental BenchmarkFundamental Benchmark(8)
Triangulation PillarTriangulation Pillar(99)
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