GEONAVIGATE INDUSTRY CHATTER

The Rock at the Bottom — From the Spudding Bit to Synthetic Diamond

5:50 · Documentary podcast

Audio MP3 · SRT captions · VTT captions

About the visuals

Historical rigs and machinery are identified by source, site and date. Unrelated drilling footage and realistic AI equipment reconstructions have been removed. Functional diagrams are explicitly conceptual; unrecorded equipment details remain unknown. Narration and timing are unchanged.

Captions are a selectable English track, not burned into the picture. The source records identify each image’s date, location and limits. These short editions retain the approved recorded narrative and chapter timing.

Transcript

At the cutting face 0.000–67.174s

Imagine standing beside an old wooden derrick. You hear a cable tighten, a heavy tool rise, and a blow travel down into the ground. Lift. Drop. Turn. Repeat. Now move forward to a modern drilling floor. The well turns out into a long lateral. Screens show torque, weight on bit, differential pressure, and rate of penetration. Somewhere beyond the heel, where nobody can watch directly, a cutting structure is meeting fresh rock. The equipment looks completely different. The basic question has survived: how do you break the next piece of formation, clear it away, and keep the hole usable? A cable-tool rig breaks formation by repeated impact. A heavy steel bit hangs below the drilling tools. The mechanism lifts it and lets it strike the bottom. A small rotation between blows helps produce a round hole. Drilling pauses for cleaning, and worn cutting edges have to be dressed again. Alberta's historical account describes this rhythm of drilling, bailing, and sharpening. There is another limit. Broken rock still occupies the hole. If you keep striking through a bed of debris, energy goes into material you have already broken. Making fragments and removing fragments are separate jobs. A useful history of drill bits has to follow both.

What the old tools actually did 67.193–115.236s

The spudding bit is a documented oilfield tool. A reproduced 1913 Oil Well Supply catalogue distinguishes it from the regular drilling bit and the reamer. The spudding bit opened the larger upper hole; the regular bit deepened it; the reamer restored diameter when needed. Those are different jobs within a drilling system. Rotary drilling moves the problem from repeated blows toward continuous rotation. The drillstring turns the cutting structure, and circulation can move fluid down through the system and return cuttings toward the surface. During the Turner Valley era, cable-tool and rotary rigs overlapped; Alberta's history describes rotary equipment becoming more prevalent during the 1920s. That overlap matters. An invention date is not the date every crew changes equipment. People use what they can obtain, repair, power, transport, and operate in the formations they actually face.

Hughes meets hard rock 115.486–160.530s

Early rotary fishtail bits scraped formation. That worked much better in some conditions than in others. In harder rock, wear and lost diameter could make progress painfully slow. The Hughes two-cone design answered with rotating toothed cutters that chipped and crushed as the bit turned. ASME identifies the 1909 design as a major engineering landmark. The Howard Hughes in this part of the story is Howard Robard Hughes Senior. The patents name the father. The later aviator and filmmaker was his son, Howard Hughes Junior. The company and the money it generated became central to the son's business empire. Imagine turning two toothed rollers against the rock. New edges keep arriving at the contact. The complete bit rotates, while its cutters rotate on their own supports. There are two movements to follow, and both matter.

Coverage at the bottom 160.780–194.559s

The familiar three-cone story has another pair of names. Floyd Scott and Lewis Garfield appear as inventors on the Hughes Tool Company patent filed in April nineteen-thirty-three and issued in December nineteen-thirty-four. Its tooth rows interfit, allowing the cutters to work across the bottom without their teeth colliding. The patent also describes a twisting component of action; a roller cone is not simply a set of perfect wheels rolling without slip. Watch the coverage. A bit must deal with the centre, the surrounding bottom, and the outer diameter. Leaving a ring or a central pedestal of unbroken formation is a different problem from merely owning a sharp tooth.

Diamond was already there 194.578–224.061s

Here is the twist in the chronology. Diamond drilling did not begin after the tricone. Rodolphe Leschot's United States patent for a diamond rock-boring tool was issued in July eighteen-sixty-three. It describes diamonds mounted around a tubular crown, cutting an annular groove and leaving a central core. Water carries away the debris. That is decades before Hughes's two-cone patents. Imagine a narrow ring being removed around a cylinder of rock. The centre remains available as a sample. That goal differs from reducing the entire bottom to cuttings.

A hard edge is not enough 224.311–289.048s

A polycrystalline diamond compact, or PDC cutter, combines a diamond cutting layer with a supporting carbide substrate. On a conventional PDC bit, cutters are mounted in the bit's blades and shear rock as the assembly rotates. Callin Joe Kerr's technical history traces PDC development from the nineteen-seventies. Early field testing exposed practical weaknesses: cutter attachment, impact damage, inadequate cutter exposure, and cleaning problems. The history describes improvements in cutter support and brazing as the technology developed. It is evidence of a difficult engineering progression, rather than instant success when synthetic diamond first appeared. Steel and tungsten-carbide matrix bodies offer different balances of strength, wear resistance, and design freedom. SLB's technical overview explains why steel supports relatively tall blades and open flow paths, while matrix bodies provide wear resistance but require attention to brittleness and geometry. Consider blade shape, the space between blades, and the routes available for fluid and cuttings. A bit that looks solid and impressive on a display stand still has to function at the bottom of a well. The empty spaces are part of its design too.

The angle and the whole tool 289.066–344.979s

Now zoom in from the entire bit to one cutter. Back rake and side rake describe different parts of its orientation. Changing that orientation changes how the cutting face meets the rock. Now add a second cutter. The design question changes again. Does it meet fresh rock, a ridge left by its neighbour, or material that has already fractured? A complete bit is an arrangement of interacting contacts, not a photograph of one ideal cutter repeated around a circle. Hybrid bits bring roller-cone and fixed PDC cutting elements into the same design. Baker Hughes describes its Kymera family as combining crushing with shearing, with intended benefits in difficult and interbedded applications. Manufacturer performance claims need their operating context; the existence of both mechanisms is the essential point here. The story has come full circle. An older mechanism can remain useful inside a newer tool. This is GeoNavigate Industry Chatter. From the spudding bit to synthetic diamond, the tool changes. The formation still gets a vote.

Visual sources and licences

Each adapted CC BY-SA image sequence remains under its source’s respective CC BY-SA licence. Source-specific attribution, links and changes appear below; other material retains its own source status.

The formation still gets a vote

Worn tricone · U.S. Geological Survey · public domain

Source / licence 1

{
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:Drill_bit_tricone_worn.jpg",
  "credit": "Worn tricone · U.S. Geological Survey · public domain",
  "license": "Public domain, USGS",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

The methods overlapped in Turner Valley

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "Original factual chronology or evidence comparison, with no equipment reconstruction.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Diamond edge, carbide support

Original explanatory schematic · conceptual and not to scale

{
  "creator": "GeoNavigate",
  "rights": "Original GeoNavigate explanatory artwork, audited for this revision.",
  "identity": "Generic cutting, coverage, core or trajectory geometry; no complete rig or named tool model is reconstructed."
}

The body carries the cutting elements

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits"
  ],
  "sourceUrl": "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits",
  "identity": "Material comparison for steel and tungsten-carbide matrix bit bodies. No inference is made about the body material of the photographed museum or Geolina163 specimen.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Inter-fitting tooth rows · original 1934 patent

U.S. patent 1,983,316 · filed 1933 / issued 1934

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US1983316A/en",
  "credit": "U.S. patent 1,983,316 · filed 1933 / issued 1934",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

The tool shapes in the 1913 catalogue

Oil Well Supply Co. · catalogue No. 32,1913 · primary plate via Petroleum History Institute

Source / licence 1 Source / licence 2 Source / licence 3

{
  "title": "Oil Well Supply Co., catalogue No. 32,1913: well drilling bits",
  "creator": "Oil Well Supply Co.",
  "date": "1913",
  "sourceUrl": "https://petroleumhistory.org/OilHistory/pages/String/bit.html",
  "catalogueRecord": "https://collections.si.edu/search/results.htm?q=%22Oil+wells--Equipment+and+supplies%22",
  "imageUrl": "https://petroleumhistory.org/OilHistory/images/DrillString/Bits1.jpg",
  "license": "Public-domain 1913 catalogue plate; only the expired original facsimile is reused, not the host’s2004 prose or modern photographs.",
  "identity": "Primary manufacturer plate explicitly labels spudding bit and drilling bits. It does not establish supply to any specific Canadian well.",
  "changes": "Faithful source plate framed beside original explanatory text; no AI restoration or tool-shape redrawing."
}

Scott and Garfield · three cones

U.S. patent 1,983,316 · filed 1933 / issued 1934

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US1983316A/en",
  "credit": "U.S. patent 1,983,316 · filed 1933 / issued 1934",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Centre. Bottom. Gauge.

Original explanatory schematic · conceptual and not to scale

{
  "creator": "GeoNavigate",
  "rights": "Original GeoNavigate explanatory artwork, audited for this revision.",
  "identity": "Generic cutting, coverage, core or trajectory geometry; no complete rig or named tool model is reconstructed."
}

Real PDC blades and the spaces between them

PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0

Source / licence 1 Source / licence 2

{
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:PDC_Meissel_Detail.jpg",
  "credit": "PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0",
  "license": "CC BY-SA 3.0",
  "changes": "Editorial framing and camera movement; source pixels not retouched.",
  "licenseUrl": "https://creativecommons.org/licenses/by-sa/3.0/"
}

Two mechanisms, combined in hybrid designs

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2 Source / licence 3 Source / licence 4 Source / licence 5

[
  {
    "creator": "GeoNavigate",
    "license": "Original GeoNavigate explanatory artwork",
    "sourceUrls": [
      "https://www.bakerhughes.com/drilling/drill-bits/hybrid-drill-bits",
      "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits"
    ],
    "sourceUrl": "https://www.bakerhughes.com/drilling/drill-bits/hybrid-drill-bits",
    "identity": "Separate real conventional tricone and PDC photographs illustrate the component mechanisms. This is not a photograph, model, cutter-count diagram or layout of a Baker Hughes Kymera bit.",
    "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
    "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
  },
  {
    "sourceUrl": "https://commons.wikimedia.org/wiki/File:Drill_bit_tricone_worn.jpg",
    "credit": "Worn tricone · U.S. Geological Survey · public domain",
    "license": "Public domain, USGS",
    "changes": "Editorial framing and camera movement; source pixels not retouched."
  },
  {
    "sourceUrl": "https://commons.wikimedia.org/wiki/File:PDC_Meissel_Detail.jpg",
    "credit": "PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0",
    "license": "CC BY-SA 3.0",
    "changes": "Editorial framing and camera movement; source pixels not retouched.",
    "licenseUrl": "https://creativecommons.org/licenses/by-sa/3.0/"
  }
]

A fixed diamond cutting structure

PDC bit · Houston Museum of Natural Science · Daderot, 2012 · CC0

Source / licence 1 Source / licence 2

{
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:Polycrystalline_Diamond_Compact_Bit_(PDC_bit,_diamond_shear_bit)_-_Houston_Museum_of_Natural_Science_-_DSC01345.JPG",
  "credit": "PDC bit · Houston Museum of Natural Science · Daderot, 2012 · CC0",
  "license": "CC0 1.0",
  "changes": "Editorial framing and camera movement; source pixels not retouched.",
  "licenseUrl": "https://creativecommons.org/publicdomain/zero/1.0/"
}

The edge that meets the rock

PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0

Source / licence 1 Source / licence 2

{
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:PDC_Meissel_Detail.jpg",
  "credit": "PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0",
  "license": "CC BY-SA 3.0",
  "changes": "Editorial framing and camera movement; source pixels not retouched.",
  "licenseUrl": "https://creativecommons.org/licenses/by-sa/3.0/"
}

Lift, drop, turn · then clean

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2 Source / licence 3

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
    "https://petroleumhistory.org/OilHistory/pages/String/bit.html",
    "https://www.petroleumhistory.org/OilHistory/pages/String/bailer.html"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "General cable-tool mechanism, shown as a motion trace rather than an invented complete rig. Stroke, rate, surface drive and particular tool model are not asserted.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

The bailer removed what the bit broke

Oil Well Supply Co. · catalogue No. 32,1913 · primary plate via Petroleum History Institute

Source / licence 1 Source / licence 2

{
  "title": "Oil Well Supply Co., catalogue No. 32,1913: well cleaning tools",
  "creator": "Oil Well Supply Co.",
  "date": "1913",
  "sourceUrl": "https://www.petroleumhistory.org/OilHistory/pages/String/bailer.html",
  "imageUrl": "https://www.petroleumhistory.org/OilHistory/images/DrillString/Bailer2.jpg",
  "license": "Public-domain 1913 catalogue plate; only the expired original facsimile is reused, not the host’s2004 prose or modern photographs.",
  "identity": "The1913 primary manufacturer plate identifies the bail, valve and dart of a regular bailer. It is a documented tool type, not an identified specimen from a named well.",
  "changes": "Source facsimile only; original explanatory text alongside, no invented rig."
}

Scott and Garfield · three cones

U.S. patent 1,983,316 · filed 1933 / issued 1934

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US1983316A/en",
  "credit": "U.S. patent 1,983,316 · filed 1933 / issued 1934",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Diamond was already there · 1863

Rodolphe Leschot · U.S. patent 39,235 · original drawing

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US39235A/en",
  "credit": "Rodolphe Leschot · U.S. patent 39,235 · original drawing",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Real PDC blades and the spaces between them

PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0

Source / licence 1 Source / licence 2

{
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:PDC_Meissel_Detail.jpg",
  "credit": "PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0",
  "license": "CC BY-SA 3.0",
  "changes": "Editorial framing and camera movement; source pixels not retouched.",
  "licenseUrl": "https://creativecommons.org/licenses/by-sa/3.0/"
}

The bailer removed what the bit broke

Oil Well Supply Co. · catalogue No. 32,1913 · primary plate via Petroleum History Institute

Source / licence 1 Source / licence 2

{
  "title": "Oil Well Supply Co., catalogue No. 32,1913: well cleaning tools",
  "creator": "Oil Well Supply Co.",
  "date": "1913",
  "sourceUrl": "https://www.petroleumhistory.org/OilHistory/pages/String/bailer.html",
  "imageUrl": "https://www.petroleumhistory.org/OilHistory/images/DrillString/Bailer2.jpg",
  "license": "Public-domain 1913 catalogue plate; only the expired original facsimile is reused, not the host’s2004 prose or modern photographs.",
  "identity": "The1913 primary manufacturer plate identifies the bail, valve and dart of a regular bailer. It is a documented tool type, not an identified specimen from a named well.",
  "changes": "Source facsimile only; original explanatory text alongside, no invented rig."
}

Diamond was already there · 1863

Rodolphe Leschot · U.S. patent 39,235 · original drawing

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US39235A/en",
  "credit": "Rodolphe Leschot · U.S. patent 39,235 · original drawing",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Roller-cone mechanism · a separate reference bit

USGS worn tricone · reference for crushing / gouging · not a hybrid product image

Source / licence 1

{
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:Drill_bit_tricone_worn.jpg",
  "credit": "Worn tricone · U.S. Geological Survey · public domain",
  "license": "Public domain, USGS",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Two rolling cutters · Hughes patent, 1909

U.S. patent 930,759 · issued 10 August 1909 · original drawing

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US930759A/en",
  "credit": "U.S. patent 930,759 · issued 10 August 1909 · original drawing",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Two mechanisms, combined in hybrid designs

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2 Source / licence 3 Source / licence 4 Source / licence 5

[
  {
    "creator": "GeoNavigate",
    "license": "Original GeoNavigate explanatory artwork",
    "sourceUrls": [
      "https://www.bakerhughes.com/drilling/drill-bits/hybrid-drill-bits",
      "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits"
    ],
    "sourceUrl": "https://www.bakerhughes.com/drilling/drill-bits/hybrid-drill-bits",
    "identity": "Separate real conventional tricone and PDC photographs illustrate the component mechanisms. This is not a photograph, model, cutter-count diagram or layout of a Baker Hughes Kymera bit.",
    "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
    "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
  },
  {
    "sourceUrl": "https://commons.wikimedia.org/wiki/File:Drill_bit_tricone_worn.jpg",
    "credit": "Worn tricone · U.S. Geological Survey · public domain",
    "license": "Public domain, USGS",
    "changes": "Editorial framing and camera movement; source pixels not retouched."
  },
  {
    "sourceUrl": "https://commons.wikimedia.org/wiki/File:PDC_Meissel_Detail.jpg",
    "credit": "PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0",
    "license": "CC BY-SA 3.0",
    "changes": "Editorial framing and camera movement; source pixels not retouched.",
    "licenseUrl": "https://creativecommons.org/licenses/by-sa/3.0/"
  }
]

Two different views of cutter orientation

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://patents.google.com/patent/US20140124270A1/en"
  ],
  "sourceUrl": "https://patents.google.com/patent/US20140124270A1/en",
  "identity": "Back rake: cutting-face tilt against a line parallel to the bit axis in side view. Side rake: cutting-face trace against the radial reference in plan view. These are plane traces, not tool silhouettes or numerical design recommendations.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Lift, drop, turn · then clean

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2 Source / licence 3

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
    "https://petroleumhistory.org/OilHistory/pages/String/bit.html",
    "https://www.petroleumhistory.org/OilHistory/pages/String/bailer.html"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "General cable-tool mechanism, shown as a motion trace rather than an invented complete rig. Stroke, rate, surface drive and particular tool model are not asserted.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Cut a ring. Keep the core.

Original explanatory schematic · conceptual and not to scale

{
  "creator": "GeoNavigate",
  "rights": "Original GeoNavigate explanatory artwork, audited for this revision.",
  "identity": "Generic cutting, coverage, core or trajectory geometry; no complete rig or named tool model is reconstructed."
}

The actual Dingman derrick · 1914

Lane and Mitchell · British Library HS85/10/28963 · public domain

Source / licence 1 Source / licence 2 Source / licence 3

{
  "title": "Derrick at Dingman Well",
  "creator": "Lane and Mitchell",
  "date": "1914",
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:Derrick_at_Dingman_Well_(HS85-10-28963).jpg",
  "institutionalCatalogue": "British Library, Canadian Copyright Collection, HS85/10/28963",
  "license": "Public domain in Canada and United States; PD-Canada and PD-US-expired on source record",
  "licenseUrl": "https://commons.wikimedia.org/wiki/File:Derrick_at_Dingman_Well_(HS85-10-28963).jpg#fileinfotpl_perm",
  "equipment_evidence": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "Dingman well wooden derrick in 1914. Alberta heritage account identifies Dingman No. 1 as cable-tool, with a separate drill shack; this cropped historical photograph does not reveal the complete drive train.",
  "changes": "Original photograph contained in an editorial plate; source detail not retouched, recoloured or AI restored."
}

Sources and credits

GeoNavigate · historical sources and image credits accompany this film

Source / licence 1

{
  "creator": "GeoNavigate",
  "rights": "Original programme closing graphic",
  "sourceUrl": "https://geonavigate.ca",
  "changes": "Public closing replaces the earlier review-status card at exactly the same frames."
}

A rolling-cutter principle with a continuing life

U.S. patent 930,759 · issued 10 August 1909 · original drawing

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US930759A/en",
  "credit": "U.S. patent 930,759 · issued 10 August 1909 · original drawing",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Lift, drop, turn · then clean

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2 Source / licence 3

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
    "https://petroleumhistory.org/OilHistory/pages/String/bit.html",
    "https://www.petroleumhistory.org/OilHistory/pages/String/bailer.html"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "General cable-tool mechanism, shown as a motion trace rather than an invented complete rig. Stroke, rate, surface drive and particular tool model are not asserted.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

The engineering was the hard part

Original explanatory schematic · conceptual and not to scale

{
  "creator": "GeoNavigate",
  "rights": "Original GeoNavigate explanatory artwork, audited for this revision.",
  "identity": "Generic cutting, coverage, core or trajectory geometry; no complete rig or named tool model is reconstructed."
}

The bit turns. The cutters roll.

U.S. patent 930,759 · issued 10 August 1909 · original drawing

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US930759A/en",
  "credit": "U.S. patent 930,759 · issued 10 August 1909 · original drawing",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Lift, drop, turn · then clean

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2 Source / licence 3

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
    "https://petroleumhistory.org/OilHistory/pages/String/bit.html",
    "https://www.petroleumhistory.org/OilHistory/pages/String/bailer.html"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "General cable-tool mechanism, shown as a motion trace rather than an invented complete rig. Stroke, rate, surface drive and particular tool model are not asserted.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Steel: strength and room for flow

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits"
  ],
  "sourceUrl": "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits",
  "identity": "Material comparison for steel and tungsten-carbide matrix bit bodies. No inference is made about the body material of the photographed museum or Geolina163 specimen.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

The bailer removed what the bit broke

Oil Well Supply Co. · catalogue No. 32,1913 · primary plate via Petroleum History Institute

Source / licence 1 Source / licence 2

{
  "title": "Oil Well Supply Co., catalogue No. 32,1913: well cleaning tools",
  "creator": "Oil Well Supply Co.",
  "date": "1913",
  "sourceUrl": "https://www.petroleumhistory.org/OilHistory/pages/String/bailer.html",
  "imageUrl": "https://www.petroleumhistory.org/OilHistory/images/DrillString/Bailer2.jpg",
  "license": "Public-domain 1913 catalogue plate; only the expired original facsimile is reused, not the host’s2004 prose or modern photographs.",
  "identity": "The1913 primary manufacturer plate identifies the bail, valve and dart of a regular bailer. It is a documented tool type, not an identified specimen from a named well.",
  "changes": "Source facsimile only; original explanatory text alongside, no invented rig."
}

The methods overlapped in Turner Valley

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "Original factual chronology or evidence comparison, with no equipment reconstruction.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

At the cutting face

Original explanatory schematic · conceptual and not to scale

{
  "creator": "GeoNavigate",
  "rights": "Original GeoNavigate explanatory artwork, audited for this revision.",
  "identity": "Generic cutting, coverage, core or trajectory geometry; no complete rig or named tool model is reconstructed."
}

Rotation and circulation

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
    "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "Conceptual normal circulation: fluid down inside drillpipe, out at the cutting zone, then up the annulus with cuttings. No rig, particular bit, casing program or hydraulic performance is reconstructed.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Lift, drop, turn · then clean

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2 Source / licence 3

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
    "https://petroleumhistory.org/OilHistory/pages/String/bit.html",
    "https://www.petroleumhistory.org/OilHistory/pages/String/bailer.html"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "General cable-tool mechanism, shown as a motion trace rather than an invented complete rig. Stroke, rate, surface drive and particular tool model are not asserted.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Early rotary drag bits met a hard-rock problem

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/who%20we%20are/engineering%20history/landmarks/246-hughes-two-cone-drill-bit-1909.pdf"
  ],
  "sourceUrl": "https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/who%20we%20are/engineering%20history/landmarks/246-hughes-two-cone-drill-bit-1909.pdf",
  "identity": "Conceptual functional relationship; no equipment or site layout is asserted.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

What the rock does to the tool

Worn tricone · U.S. Geological Survey · public domain

Source / licence 1

{
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:Drill_bit_tricone_worn.jpg",
  "credit": "Worn tricone · U.S. Geological Survey · public domain",
  "license": "Public domain, USGS",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

Howard R. Hughes Senior · 1909

U.S. patent 930,759 · issued 10 August 1909 · original drawing

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US930759A/en",
  "credit": "U.S. patent 930,759 · issued 10 August 1909 · original drawing",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

PDC mechanism · a separate reference bit

Geolina163 · PDC cutting face, 2004 · CC BY-SA 3.0 · separate mechanism reference

Source / licence 1 Source / licence 2

{
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:PDC_Meissel_Detail.jpg",
  "credit": "PDC cutting face · Geolina163, 2004 · CC BY-SA 3.0",
  "license": "CC BY-SA 3.0",
  "changes": "Editorial framing and camera movement; source pixels not retouched.",
  "licenseUrl": "https://creativecommons.org/licenses/by-sa/3.0/"
}

Three jobs at the hole

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://petroleumhistory.org/OilHistory/pages/String/bit.html"
  ],
  "sourceUrl": "https://petroleumhistory.org/OilHistory/pages/String/bit.html",
  "identity": "Original factual chronology or evidence comparison, with no equipment reconstruction.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Rotation and circulation

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1 Source / licence 2

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
    "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "Conceptual normal circulation: fluid down inside drillpipe, out at the cutting zone, then up the annulus with cuttings. No rig, particular bit, casing program or hydraulic performance is reconstructed.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Howard R. Hughes Senior · 1909

U.S. patent 930,759 · issued 10 August 1909 · original drawing

Source / licence 1

{
  "sourceUrl": "https://patents.google.com/patent/US930759A/en",
  "credit": "U.S. patent 930,759 · issued 10 August 1909 · original drawing",
  "license": "Historical U.S. patent drawing",
  "changes": "Editorial framing and camera movement; source pixels not retouched."
}

PDC took engineering work in the field

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://ptacts.uspto.gov/ptacts/public-informations/petitions/1517717/download-documents?artifactId=SwlXeV8tknekr20AuPvXBWoPlPJP1wyny0k18VjqZ9W2QskxZUlj8Qo"
  ],
  "sourceUrl": "https://ptacts.uspto.gov/ptacts/public-informations/petitions/1517717/download-documents?artifactId=SwlXeV8tknekr20AuPvXBWoPlPJP1wyny0k18VjqZ9W2QskxZUlj8Qo",
  "identity": "Original factual chronology or evidence comparison, with no equipment reconstruction.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

PDC took engineering work in the field

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://ptacts.uspto.gov/ptacts/public-informations/petitions/1517717/download-documents?artifactId=SwlXeV8tknekr20AuPvXBWoPlPJP1wyny0k18VjqZ9W2QskxZUlj8Qo"
  ],
  "sourceUrl": "https://ptacts.uspto.gov/ptacts/public-informations/petitions/1517717/download-documents?artifactId=SwlXeV8tknekr20AuPvXBWoPlPJP1wyny0k18VjqZ9W2QskxZUlj8Qo",
  "identity": "Original factual chronology or evidence comparison, with no equipment reconstruction.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Matrix: abrasion resistance and design limits

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits"
  ],
  "sourceUrl": "https://www.slb.com/resource-library/oilfield-review/defining-series/defining-bits",
  "identity": "Material comparison for steel and tungsten-carbide matrix bit bodies. No inference is made about the body material of the photographed museum or Geolina163 specimen.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

Two different views of cutter orientation

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://patents.google.com/patent/US20140124270A1/en"
  ],
  "sourceUrl": "https://patents.google.com/patent/US20140124270A1/en",
  "identity": "Back rake: cutting-face tilt against a line parallel to the bit axis in side view. Side rake: cutting-face trace against the radial reference in plan view. These are plane traces, not tool silhouettes or numerical design recommendations.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

The actual Dingman derrick · 1914

Lane and Mitchell · British Library HS85/10/28963 · public domain

Source / licence 1 Source / licence 2 Source / licence 3

{
  "title": "Derrick at Dingman Well",
  "creator": "Lane and Mitchell",
  "date": "1914",
  "sourceUrl": "https://commons.wikimedia.org/wiki/File:Derrick_at_Dingman_Well_(HS85-10-28963).jpg",
  "institutionalCatalogue": "British Library, Canadian Copyright Collection, HS85/10/28963",
  "license": "Public domain in Canada and United States; PD-Canada and PD-US-expired on source record",
  "licenseUrl": "https://commons.wikimedia.org/wiki/File:Derrick_at_Dingman_Well_(HS85-10-28963).jpg#fileinfotpl_perm",
  "equipment_evidence": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "Dingman well wooden derrick in 1914. Alberta heritage account identifies Dingman No. 1 as cable-tool, with a separate drill shack; this cropped historical photograph does not reveal the complete drive train.",
  "changes": "Original photograph contained in an editorial plate; source detail not retouched, recoloured or AI restored."
}

The methods overlapped in Turner Valley

GeoNavigate · source-based explanatory graphic · conceptual, not to scale

Source / licence 1

{
  "creator": "GeoNavigate",
  "license": "Original GeoNavigate explanatory artwork",
  "sourceUrls": [
    "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx"
  ],
  "sourceUrl": "https://www.history.alberta.ca/energyheritage/turner-valley-gas-plant/technology-and-infrastructure/drilling.aspx",
  "identity": "Original factual chronology or evidence comparison, with no equipment reconstruction.",
  "changes": "New factual diagram; no AI-generated equipment or photorealistic reconstruction.",
  "equipment_policy": "Functional/geometrical principle only; no invented rig, equipment silhouette or historical apparatus model."
}

The tool shapes in the 1913 catalogue

Oil Well Supply Co. · catalogue No. 32,1913 · primary plate via Petroleum History Institute

Source / licence 1 Source / licence 2 Source / licence 3

{
  "title": "Oil Well Supply Co., catalogue No. 32,1913: well drilling bits",
  "creator": "Oil Well Supply Co.",
  "date": "1913",
  "sourceUrl": "https://petroleumhistory.org/OilHistory/pages/String/bit.html",
  "catalogueRecord": "https://collections.si.edu/search/results.htm?q=%22Oil+wells--Equipment+and+supplies%22",
  "imageUrl": "https://petroleumhistory.org/OilHistory/images/DrillString/Bits1.jpg",
  "license": "Public-domain 1913 catalogue plate; only the expired original facsimile is reused, not the host’s2004 prose or modern photographs.",
  "identity": "Primary manufacturer plate explicitly labels spudding bit and drilling bits. It does not establish supply to any specific Canadian well.",
  "changes": "Faithful source plate framed beside original explanatory text; no AI restoration or tool-shape redrawing."
}

Equipment corrections by interval

ShotSecondsCorrection
10.000–5.292Replace invented old wooden rig with the documented1914 Dingman cable-tool derrick. General cable-tool explanation is explicitly tied to an identified real example.
25.292–10.583Remove a generic invented derrick. Retain only the source-supported repeated impact, small turn between blows and separate cleaning cycle.
624.083–28.583Replace idealized unverified bit/bailer silhouettes with the actual1913 manufacturer illustration of the named cleaning tool.
833.125–38.125Remove a generic invented derrick. Retain only the source-supported repeated impact, small turn between blows and separate cleaning cycle.
938.125–43.125Replace invented old wooden rig with the documented1914 Dingman cable-tool derrick. General cable-tool explanation is explicitly tied to an identified real example.
1043.125–48.125Remove a generic invented derrick. Retain only the source-supported repeated impact, small turn between blows and separate cleaning cycle.
1148.125–53.167Remove a generic invented derrick. Retain only the source-supported repeated impact, small turn between blows and separate cleaning cycle.
1253.167–57.833Replace idealized unverified bit/bailer silhouettes with the actual1913 manufacturer illustration of the named cleaning tool.
1357.833–62.500Remove a generic invented derrick. Retain only the source-supported repeated impact, small turn between blows and separate cleaning cycle.
1462.500–67.167Replace idealized unverified bit/bailer silhouettes with the actual1913 manufacturer illustration of the named cleaning tool.
1567.167–73.083Replace invented spudding tool and old-rig silhouettes with the primary1913 catalogue’s actual spudding and drilling-bit drawings.
1673.083–79.000Replace invented spudding tool and old-rig silhouettes with the primary1913 catalogue’s actual spudding and drilling-bit drawings.
1779.000–84.917The previous invented spudding/drilling/reaming silhouettes were not traced to precise tools. This functional comparison asserts only the documented jobs.
1884.917–91.417Remove unrelated modern EagleFord research rig and replace the oversimplified circulation graphic with explicit pipe bore/annulus paths. The source rig’s downhole bit and operating method were unverified.
1991.417–97.917Remove unrelated modern EagleFord research rig and replace the oversimplified circulation graphic with explicit pipe bore/annulus paths. The source rig’s downhole bit and operating method were unverified.
2097.917–104.458Remove unrelated modern research-rig and1870s Petrolia crew footage from1920s Turner Valley adoption; use the specifically documented cable-tool/rotary sequence.
21104.458–109.875Remove unrelated modern research-rig and1870s Petrolia crew footage from1920s Turner Valley adoption; use the specifically documented cable-tool/rotary sequence.
22109.875–115.250Remove unrelated modern research-rig and1870s Petrolia crew footage from1920s Turner Valley adoption; use the specifically documented cable-tool/rotary sequence.
23115.250–120.000A modern three-cone bit is the wrong tool for the early fishtail/two-cone transition. Remove it; explain the documented problem without inventing a fishtail silhouette.
34171.958–177.667A modern worn USGS bit cannot verify the 1934 patent’s specific inter-fitting tooth geometry. Show the original Scott–Garfield patent drawing.
47237.583–243.042Remove modern museum/research-rig imagery from an account of1970s field trials; no evidence identified those specimens or tools as the development hardware.
50253.917–259.375Remove modern museum/research-rig imagery from an account of1970s field trials; no evidence identified those specimens or tools as the development hardware.
51259.375–264.833Do not imply unverified body materials from a generic PDC photograph, or confuse an individual cutter’s carbide substrate with the bit body. Use the supported material comparison.
52264.833–270.333Do not imply unverified body materials from a generic PDC photograph, or confuse an individual cutter’s carbide substrate with the bit body. Use the supported material comparison.
53270.333–275.792Do not imply unverified body materials from a generic PDC photograph, or confuse an individual cutter’s carbide substrate with the bit body. Use the supported material comparison.
55280.208–284.625Remove generic well circulation/research-rig pictures from the blade/flow-space paragraph. Use an actual identified PDC cutting face showing its blades and intervening spaces.
56284.625–289.042Remove generic well circulation/research-rig pictures from the blade/flow-space paragraph. Use an actual identified PDC cutting face showing its blades and intervening spaces.
57289.042–294.042Correct the old rake graphic, which repeated a side-view shape in its plan-view panel. Draw distinct side and plan projections with their proper reference directions.
61308.500–313.208Correct the old rake graphic, which repeated a side-view shape in its plan-view panel. Draw distinct side and plan projections with their proper reference directions.
62313.208–317.792Remove an invented hybrid cutter layout. Real separate tool references illustrate crushing/gouging and shearing, explicitly without claiming a Kymera product image or specific model.
63317.792–322.375The photo is retained as a labelled separate roller-cone mechanism reference, not a complete Kymera hybrid product.
64322.375–326.958The photo is retained as a labelled separate conventional PDC mechanism reference, not a complete Kymera hybrid product.
65326.958–331.583Remove an invented hybrid cutter layout. Real separate tool references illustrate crushing/gouging and shearing, explicitly without claiming a Kymera product image or specific model.
66331.583–336.667Remove unrelated modern research rig. Return to the actual1909 rolling-cutter patent as the narration notes that an older mechanism continues inside a newer design.

Research sources