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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


December 2004
Flush BracketG3645 - Culham Bridge
Cut Bench MarkWallingford, St Mary's Church
September 2004
Cut Bench MarkThame, Baptist Church
Cut Bench MarkThame, St. Mary's Church
Flush Bracket2008 - Thame, Thame Park
Flush Bracket2006 - Thame Railway Station
Flush Bracket2001 - Thame, St. Mary's Church
Flush Bracket1986 - Thame, Upper High Street
Flush Bracket1999 - Long Crendon
Flush Bracket1998 - Long Crendon, Church End
Flush Bracket2012 - Stoke Talmage
Cut Bench Mark with BoltReading, St Mary's Church
Cut Bench MarkReading, 33 London Street
Cut Bench MarkReading, High Bridge
Projecting BracketReading Town Hall
Projecting BracketReading, Greyfriars Church
Flush Bracket1030 - Bix
Flush Bracket1026 - Henley Bridge
Flush Bracket1025 - Henley-on-Thames
Flush Bracket1023 - Remenham Hill, Five Horse Shoes PH
Flush Bracket1031 - Nuffield
Flush Bracket22 - Shillingford Bridge
Flush Bracket2033 - Allnutt's Barn
Flush Bracket2032 - Ewelme
August 2004
Flush Bracket25 - Clifton Hampden, Clifton Lock
Flush Bracket24 - Clifton Hampden Bridge
Triangulation PillarS2521 - St Catherines Hill
Triangulation PillarS2479 - Mount Joy
Cut Bench MarkChale, St Catherine's Oratory
Triangulation PillarS2517 - Wroxall Down
Destroyed4 - Pangbourne, Whitchurch Bridge
Destroyed3 - Mapledurham Lock
Destroyed7 - Cleeve Mill
Cut Bench MarkPangbourne, Sot's Hole
Cut Bench MarkPangbourne, Whitchurch Bridge
Flush Bracket9 - North Stoke, Church
Flush Bracket8 - Moulsford, Beetle and Wedge Inn
Flush Bracket75 - Appletree Eyot
Flush Bracket5 - Sot's Hole
Flush Bracket27 - Culham Lock Bridge
Cut Bench MarkFordham, St Peter's Church
July 2004
Projecting BracketCulham Bridge
Projecting BracketMoulsford Viaduct
Triangulation PillarS7542 - Castle Rising
Flush Bracket10 - Newnham Murren
Triangulation PillarS8068 - High Bridge Farm
Triangulation PillarS5907 - Crafts Hill
Triangulation PillarS8635 - Oakington
Cut Bench MarkCambridge, Sidney Street
Cut Bench MarkCambridge, Round Church
Cut Bench MarkCambridge, Christ's College
Cut Bench Mark with BoltCambridge, Great Bridge
Cut Bench MarkWoburn, Staunton House
Cut Bench MarkCambridge, St John's College
Flush Bracket11 - Wallingford Bridge
Triangulation PillarS4909 - Nuffield
Flush Bracket1029 - Nettlebed
Triangulation PillarS9369 - Monk Field
Triangulation PillarS5882 - Rogues Lane
Triangulation PillarS5798 - Kings Bush
June 2004
Triangulation PillarS1984 - Chalk Farm
Triangulation PillarS4365 - Gog Magog
Cut Bench MarkCholsey, St Mary's Church
Triangulation PillarS5729 - Grims Ditch
Fundamental BenchmarkWallingford FBM
Triangulation PillarS5730 - Pit Plantation
Triangulation PillarS5725 - Farnborough
Triangulation PillarS5074 - Coton
Triangulation Pillar11155 - Littlebury Hedge
Triangulation PillarS3700 - Hurst Hill
Triangulation PillarS5540 - Brightwell Barrow
January 2004
Triangulation PillarS6207 - Monument Hill


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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