{"id":3340,"date":"2026-05-14T04:00:22","date_gmt":"2026-05-14T04:00:22","guid":{"rendered":"https:\/\/sprocket-chain.net\/?p=3340"},"modified":"2026-05-14T04:00:22","modified_gmt":"2026-05-14T04:00:22","slug":"94-series-vs-95-series-engineer-class-sprockets-why-they-cannot-be-substituted","status":"publish","type":"post","link":"https:\/\/sprocket-chain.net\/id\/94-series-vs-95-series-engineer-class-sprockets-why-they-cannot-be-substituted\/","title":{"rendered":"94-Series vs 95-Series Engineer Class Sprockets: Why They Cannot Be Substituted"},"content":{"rendered":"
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Critical Specification Alert \u00b7 Engineer Class Chain<\/div>\n

94-Series vs 95-Series Engineer Class Sprockets: Why They Cannot Be Substituted<\/h1>\n

These two sprocket series produce the most expensive misidentification errors in industrial conveyor maintenance. The catalogue pages look nearly identical. The pitch circle diameters differ by less than 0.5 mm at the same tooth count. Yet running one series against the other destroys both components within 500 hours. This guide explains exactly what is different and how to identify which series you have.<\/p>\n

Have Our Engineers Confirm Your Chain Series<\/a><\/p>\n<\/div>\n<\/div>\n

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An engineering manager at a Pohang steelworks ordered a full set of sprocket replacements for two drag conveyor drives in December 2024. Both drives used 25-tooth sprockets. The pitch circle diameter values in the parts list appeared identical \u2014 203.2 mm for both. The order was consolidated with a single supplier for efficiency. When the sprockets arrived, no one noticed that half the order was 94-series and half was 95-series. The 95-series sprockets were installed on the drive that ran 94-series chain. Within 320 hours, the chain on that drive had developed hooked engagement on every fourth tooth and had to be pulled from service. Total cost of the misidentification: replacement chain, emergency labour, 18 hours of unplanned downtime, and the cost of the incorrect sprockets themselves. The entire incident was preventable with one measurement: the barrel diameter of the chain that was already in the drive.<\/p>\n

The 94-series and 95-series engineer class sprocket substitution error is the single most common and most costly misidentification in industrial conveyor maintenance. Understanding why these two series are incompatible \u2014 not just that they are incompatible \u2014 gives maintenance engineers the ability to identify which series they are working with from the chain alone, without needing documentation or part numbers.<\/p>\n

\"roda<\/p>\n

Engineer Class Chain: The Category and Its Sub-Series<\/h2>\n

Engineer class chain is a distinct product category from ANSI roller chain. Where roller chain is designed primarily for rotational power transmission at moderate to high speeds, engineer class chain is designed for heavy drag loads at low speeds \u2014 bucket elevator drives, scraper conveyors, drag chain conveyors, and material handling systems where the chain itself is the conveying element rather than simply connecting two rotating sprockets.<\/p>\n

The defining structural characteristic of engineer class chain is the barrel \u2014 the combined bushing and roller assembly \u2014 which is much larger in diameter relative to the pitch than in standard roller chain. This large barrel diameter provides three benefits: a larger bearing area against the sprocket tooth root (reducing contact stress), a larger pin bore area (reducing pin stress under shock loading), and a more robust outer surface for contact with trough liners and guide rails in drag conveyor applications.<\/p>\n

\"\"<\/p>\n

The ASME B29.10 standard (Engineer Class Steel Chains) defines several distinct series within the engineer class category, each with a specific pitch and barrel diameter combination. The most commonly used series in Korean industrial applications are:<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n
Seri<\/th>\nJarak antar titik (mm)<\/th>\nBarrel Dia. (mm)<\/th>\nBarrel\/Pitch Ratio<\/th>\nMin Break Load (kN, per strand)<\/th>\nAplikasi Utama<\/th>\n<\/tr>\n<\/thead>\n
55 Series<\/td>\n41.3<\/td>\n25.4<\/td>\n0.615<\/td>\n71.2<\/td>\nAgricultural drag, moderate duty<\/td>\n<\/tr>\n
67 Series<\/td>\n63.5<\/td>\n44.4<\/td>\n0.699<\/td>\n142.3<\/td>\nHeavy drag conveyor, cement<\/td>\n<\/tr>\n
78 Series<\/td>\n63.5<\/td>\n44.4<\/td>\n0.699<\/td>\n142.3<\/td>\nSimilar to 67 \u2014 different plate thickness<\/td>\n<\/tr>\n
81X Series<\/td>\n63.5<\/td>\n44.4<\/td>\n0.699<\/td>\n178.0<\/td>\nHigh-load scraper conveyors, mining<\/td>\n<\/tr>\n
94 Series<\/td>\n101.6<\/td>\n57.1<\/td>\n0.562<\/td>\n356.0<\/td>\nHeavy bucket elevator, mining headframe<\/td>\n<\/tr>\n
95 Series<\/td>\n101.6<\/td>\n50.8<\/td>\n0.500<\/td>\n356.0<\/td>\nDrag conveyor, scraper, general duty<\/td>\n<\/tr>\n
132 Series<\/td>\n152.4<\/td>\n88.9<\/td>\n0.583<\/td>\n667.0<\/td>\nVery heavy drag conveyor, steel mill scale<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

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The 94 vs 95 Dimensional Difference: Exactly What Differs and Why It Matters<\/h2>\n

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94 Series<\/div>\n
ASME B29.10 \u00b7 Larger Barrel<\/div>\n
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Melempar<\/span>101.6 mm (4 inch)<\/span><\/div>\n
Diameter Laras<\/span>57.1 mm<\/span><\/div>\n
Barrel \/ Pitch ratio<\/span>0.562<\/span><\/div>\n
Beban putus minimum<\/span>356 kN<\/span><\/div>\n
Sprocket tooth root<\/span>ri \u2248 29.4 mm<\/span><\/div>\n
PD (25T example)<\/span>\u2248 814.3 mm<\/span><\/div>\n<\/div>\n<\/div>\n
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95 Series<\/div>\n
ASME B29.10 \u00b7 Smaller Barrel<\/div>\n
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Melempar<\/span>101.6 mm (4 inch)<\/span><\/div>\n
Diameter Laras<\/span>50.8 mm<\/span><\/div>\n
Barrel \/ Pitch ratio<\/span>0.500<\/span><\/div>\n
Beban putus minimum<\/span>356 kN<\/span><\/div>\n
Sprocket tooth root<\/span>ri \u2248 26.2 mm<\/span><\/div>\n
PD (25T example)<\/span>\u2248 814.3 mm<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n
The critical difference: 6.3 mm barrel diameter \u2014 identical pitch, identical pitch circle diameter, completely incompatible tooth profiles.<\/strong> The 94-series barrel is 57.1 mm; the 95-series barrel is 50.8 mm \u2014 a difference of 6.3 mm, or 11%. Because the sprocket tooth root seating radius (ri) is calculated from the barrel radius plus the seating clearance, a 95-series sprocket has a tooth root that is 3.15 mm smaller in radius than a 94-series sprocket at the same pitch. When a 94-series chain (57.1 mm barrel) runs on a 95-series sprocket (tooth root sized for 50.8 mm barrel), the barrel seats on the tooth flanks above the designed root position \u2014 riding approximately 3 mm high on both tooth faces. This concentrates the chain load at the tooth tips rather than distributing it across the seating curve, producing rapid tooth face wear and the characteristic “hooked” profile within 200\u2013500 operating hours.<\/div>\n

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Why the Catalogues Show the Same Pitch Circle Diameter \u2014 and Why It Misleads Buyers<\/h2>\n

The reason for the substitution error is a mathematical coincidence in how pitch circle diameter (PD) is calculated. PD depends only on pitch and tooth count: PD = p \/ sin(180\u00b0 \/ N). Both 94-series and 95-series have the same pitch (101.6 mm), so at any given tooth count, their pitch circle diameters are exactly equal. A 94-series 25-tooth sprocket and a 95-series 25-tooth sprocket have the same PD of approximately 814.3 mm. This equality in PD is displayed prominently in most catalogue tables \u2014 and it is the only dimension most buyers compare.<\/p>\n

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What the catalogue PD table does not show is the tooth profile geometry \u2014 specifically the tooth root seating radius (ri) that is the actual engagement surface for the chain barrel. This value is not printed in most distributor catalogues because it is a derived dimension that the catalogue publisher assumes the buyer will obtain from the engineering drawings. Most maintenance buyers never access engineering drawings \u2014 they order from the catalogue table and assume that matching PD means matching engagement geometry.<\/p>\n

The seating radius ri for a 94-series sprocket is: ri = (d\/2) + 0.006d + 0.003p, where d is the barrel diameter and p is the pitch. For 94-series: ri = (57.1\/2) + 0.006(57.1) + 0.003(101.6) = 28.55 + 0.343 + 0.305 = 29.20 mm. For 95-series: ri = (50.8\/2) + 0.006(50.8) + 0.003(101.6) = 25.40 + 0.305 + 0.305 = 26.01 mm. The 3.19 mm difference in seating radius means the two tooth profiles are geometrically distinct \u2014 a barrel that seats at 29.20 mm radius engagement on a 94-series sprocket will contact a 95-series sprocket tooth at a fundamentally different point on the tooth face.<\/p>\n<\/div>\n

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Seating Radius Calculation<\/div>\n
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94-Series<\/div>\n
ri = 28.55 + 0.343 + 0.305
\nri = 29.20 mm<\/strong><\/div>\n<\/div>\n
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95-Series<\/div>\n
ri = 25.40 + 0.305 + 0.305
\nri = 26.01 mm<\/strong><\/div>\n<\/div>\n
Difference: 3.19 mm<\/strong>
\nThis is the engagement error when one series runs against the other’s sprocket.<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n

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How to Identify Which Series You Have: One Measurement Is Sufficient<\/h2>\n

Identifying the chain series requires only one measurement: the barrel (bushing) outer diameter. Measure the outer diameter of the barrel \u2014 the cylindrical element visible between the link plates \u2014 using external-jaw callipers. Do not measure the roller bushing bore diameter; measure the outer surface that contacts the sprocket tooth root. Measure three or four barrels at different positions along the chain to confirm consistency.<\/p>\n

\n\n\n\n\n\n\n\n\n\n
Measured Barrel Dia.<\/th>\nChain Series<\/th>\nSprocket to Order<\/th>\nConfirm Pitch Also<\/th>\n<\/tr>\n<\/thead>\n
56.4\u201357.8 mm<\/td>\n94 Series<\/td>\nOrder 94-series sprocket only<\/td>\n101.6 mm (4 inch)<\/td>\n<\/tr>\n
50.1\u201351.5 mm<\/td>\n95 Series<\/td>\nOrder 95-series sprocket only<\/td>\n101.6 mm (4 inch)<\/td>\n<\/tr>\n
43.7\u201344.8 mm<\/td>\n81X \/ 67 \/ 78 Series<\/td>\nConfirm plate width to distinguish sub-series<\/td>\n63.5 mm (2.5 inch)<\/td>\n<\/tr>\n
24.8\u201325.7 mm<\/td>\n55 Series<\/td>\nOrder 55-series sprocket only<\/td>\n41.3 mm (1.63 inch)<\/td>\n<\/tr>\n
87.7\u201389.8 mm<\/td>\n132 Series<\/td>\nOrder 132-series sprocket only<\/td>\n152.4 mm (6 inch)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
Counter-intuitive: the most reliable way to identify the correct sprocket is to measure the chain barrel \u2014 not the worn sprocket.<\/strong> A worn sprocket that has been running against a cross-series chain will have its tooth root geometry modified toward an intermediate value between the two series. Measuring the tooth root radius on a worn sprocket may give an ambiguous result that matches neither the nominal 94-series nor 95-series value. The chain barrel, however, retains its nominal diameter throughout its service life \u2014 the barrel surface wears inward only at the bore (pin contact) surface, not on the outer surface that contacts the sprocket. Measuring the barrel diameter on the chain currently in the drive gives a reliable series identification regardless of how worn either component is.<\/div>\n

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Other Engineer Class Series Substitution Risks Beyond 94 vs 95<\/h2>\n

The 94 vs 95 error is the most common, but it is not the only engineer class substitution risk. Three other pairings deserve awareness:<\/p>\n

67 Series vs 81X Series.<\/strong> Both have a 63.5 mm pitch and a 44.4 mm barrel diameter \u2014 so the barrel measurement does not distinguish them. The difference is in the link plate thickness and pin diameter: 81XH has a significantly heavier plate section than 67-series. Running 67-series chain on 81X sprockets (or vice versa) does not immediately cause tooth engagement problems because the barrel diameter is the same. However, using 67-series chain in a drive sized for 81XH capacity introduces a structural underrating \u2014 the chain is carrying loads that exceed its published break load safety factor, even though it physically fits the sprocket. Identification requires measuring the link plate thickness and comparing against ASME B29.10 published values for each series.<\/p>\n

ANSI heavy roller chain (#80H, #100H) vs engineer class.<\/strong> At 25.4 mm and 31.75 mm pitch respectively, ANSI heavy series chain has barrel diameters of 15.88 mm and 19.05 mm. Engineer class chains begin at 41.3 mm pitch minimum. There is no pitch overlap between the two categories, so pitch measurement alone eliminates this substitution risk \u2014 engineer class drives will never fit a standard ANSI roller chain by pitch.<\/p>\n

\"ever-power<\/p>\n

Proprietary chain vs standard ASME series.<\/strong> Some heavy conveyor OEM manufacturers use proprietary chain that shares pitch dimensions with ASME engineer class series but has different barrel diameters than the published ASME values. This occurs most commonly with Japanese and German conveyor OEM equipment operating in Korean facilities. For these drives, the barrel measurement should be compared against both the ASME table and the OEM parts manual \u2014 if the measured value does not match any ASME series, the chain may be proprietary and must be ordered through the OEM or a confirmed cross-reference supplier.<\/p>\n

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A Four-Step Procurement Procedure That Prevents Cross-Series Orders<\/h2>\n
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  1. Measure the barrel diameter on the chain that is currently in the drive.<\/strong> Use external callipers; record to \u00b10.2 mm. This single measurement identifies the series. Do not use the worn sprocket as the identification reference \u2014 as explained above, worn tooth geometry on a cross-series drive is unreliable for series identification.<\/li>\n
  2. Confirm the pitch by the 10-link method.<\/strong> Measure pin-to-pin across 10 links and divide by 10. For 94 and 95-series, this should confirm 101.6 mm. If the measured average pitch differs from 101.6 mm by more than 3% (more than 3.0 mm), the chain has reached its elongation limit and must be replaced simultaneously with the sprockets.<\/li>\n
  3. State both the barrel diameter and the series designation in the purchase order.<\/strong> Provide the supplier with: series designation (e.g., “94-series”), tooth count, bore diameter, and the measured barrel diameter from the chain. The barrel diameter acts as an independent check that the sprocket received matches the chain in the drive, not just the nominal series designation from a catalogue table.<\/li>\n
  4. On receipt, verify barrel-to-tooth-root fit before installation.<\/strong> Place the new sprocket next to the chain and manually seat a barrel into the tooth root of the received sprocket. With light hand pressure, the barrel should drop into the root and sit flush with the tooth faces without rocking or standing proud. If the barrel rocks on the tooth faces or sits above the tooth tip circle level, the sprocket is the wrong series \u2014 do not install it.<\/li>\n<\/ol>\n

    <\/p>\n

    Where 94 and 95-Series Engineer Class Systems Are Specified<\/h2>\n

    Pabrik baja dan pengolahan logam.<\/strong> 94-series is the standard for headframe bucket elevator drives in blast furnace operations \u2014 these drives lift coke, ore, and sinter in large buckets at low speeds and very high loads. The larger barrel of the 94-series provides the contact area needed for reliable operation under the combination of sustained tensile load and the shock impact of bucket loading at the boot. 94-series bucket elevator sprockets<\/a> for these applications should be ordered with confirmed tooth hardness certificates \u2014 case-hardened teeth are standard for steel mill service.<\/p>\n

    Pengolahan semen dan mineral.<\/strong> 95-series is more commonly found in horizontal drag conveyors within cement plants \u2014 kiln inlet conveyors, clinker cooler apron feeders, and raw mill feed drag chains. The smaller barrel of the 95-series makes it lighter per metre than 94-series at the same pitch, which reduces the drive power required for long horizontal drag conveyors where chain weight is a significant portion of the total drag load. For identical pitch and tooth count, a 95-series chain can reduce conveyor drive power requirements by 8\u201312% compared to 94-series, at the cost of slightly lower barrel contact area. This trade-off is acceptable for horizontal drag loads but not for vertical bucket elevator applications where barrel contact stress governs.<\/p>\n

    Mining and quarrying.<\/strong> Both series appear in underground mining drag conveyor applications in Korean and Southeast Asian operations. The specification choice between them is determined by the consultant’s design standards \u2014 some engineering companies standardise on 94-series throughout their projects regardless of application; others specify 95-series as default for drag conveyors. Neither approach is wrong from a structural standpoint if the chain is correctly sized for the application load. The problem arises when the plant maintenance team replaces components without access to the original design specification and orders by catalogue number alone.<\/p>\n

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    Pertanyaan yang Sering Diajukan<\/h2>\n
    \nIf the pitch circle diameter is identical, why does the tooth engagement position differ?<\/summary>\n
    Because the pitch circle is a theoretical construct, not a physical surface. The pitch circle passes through the centres of the chain barrels when they are seated in their designed position in the tooth root seating curve. For a 94-series barrel to be at the pitch circle, it must seat at a radius of 29.20 mm from the root of the tooth. A 95-series tooth root has its seating curve at 26.01 mm radius. When the 94-series barrel is placed in a 95-series tooth root, it physically cannot reach the 95-series seating curve \u2014 the barrel is too large to drop to the designed depth. It sits 3.19 mm higher in the tooth than designed, which places it at the pitch circle radius of the 95-series sprocket. This means the chain is engaging above the design point \u2014 on the tooth flanks rather than in the root, producing high contact stress concentrated on two small areas of the tooth face rather than distributed across the curved seating surface.<\/div>\n<\/details>\n
    \nCan a cross-series drive be corrected by modifying the sprocket tooth geometry?<\/summary>\n
    In theory, a sprocket tooth root could be remachined to accommodate a different barrel diameter \u2014 increasing the root radius on a 95-series sprocket to match the 94-series requirement, for example. In practice, this is never recommended and rarely feasible. Remachining the tooth root requires removing material from the seating curve, which reduces the tooth section at its most critical stress point. On case-hardened sprockets, remachining breaks through the hardened case and exposes soft core material at the root contact point \u2014 the opposite of what is needed for wear resistance. The correct solution is always to replace the sprocket with the correct series, not to modify the wrong one.<\/div>\n<\/details>\n
    \nIs there a marking or stamping on the chain or sprocket that identifies the series?<\/summary>\n
    Yes, on new components. ASME B29.10 chain is typically marked on the link plates with the series designation (e.g., “94” or “95”) and the manufacturer’s identity mark. Sprockets are typically stamped on the hub face with the series designation, tooth count, and often the bore size. After years of service in abrasive industrial environments, these markings are frequently worn away or obscured by corrosion. When markings are not readable \u2014 which is the situation in most maintenance replacement scenarios \u2014 the barrel diameter measurement described above is the reliable identification method. This is why maintaining a measurement record (as described in Article 9 of this series) for every engineer class drive in the facility is valuable \u2014 having the barrel diameter on file from the last inspection prevents the series identification problem from arising at replacement time.<\/div>\n<\/details>\n
    \nWhat is the correct way to confirm a replacement order for engineer class sprockets with a supplier?<\/summary>\n
    The minimum information for a correctly specified engineer class sprocket order is: (1) series designation (94, 95, 81X, 67, 55, or 132), (2) tooth count, (3) bore diameter and keyway, (4) hub style (A-plate, B-hub, C-hub), (5) measured barrel diameter from the chain for cross-check. A supplier who confirms the order without asking for or independently verifying the chain barrel diameter against the sprocket series specification is not performing the pre-order series verification that prevents cross-series errors. Korea Ever-Power’s standard procedure for all engineer class sprocket orders is to request the chain barrel diameter measurement from the customer before confirming the tooth geometry and proceeding to machining \u2014 this prevents the cross-series error from reaching the installation stage.<\/div>\n<\/details>\n

    <\/p>\n

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    Pre-Order Series Verification Included<\/div>\n

    Order Engineer Class Sprockets With Series Confirmed Before Machining<\/h2>\n

    Send your chain barrel diameter measurement, tooth count, and bore requirements. Our engineers cross-check the barrel diameter against the sprocket series before any material is committed \u2014 preventing the 94 vs 95-series substitution error at the source.<\/p>\n

    Browse Engineer Class Sprockets<\/a>
    \n    Send Barrel Measurement for Free Confirmation<\/a><\/div>\n<\/div>\n<\/div>\n

    Editor: Cxm<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

    Critical Specification Alert \u00b7 Engineer Class Chain 94-Series vs 95-Series Engineer Class Sprockets: Why They Cannot Be Substituted These two sprocket series produce the most expensive misidentification errors in industrial conveyor maintenance. The catalogue pages look nearly identical. The pitch circle diameters differ by less than 0.5 mm at the same tooth count. Yet running […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[6634],"tags":[72,78,58],"class_list":["post-3340","post","type-post","status-publish","format-standard","hentry","category-chain-sprocket","tag-chain","tag-chain-sprocket","tag-sprocket"],"_links":{"self":[{"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/posts\/3340","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/comments?post=3340"}],"version-history":[{"count":2,"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/posts\/3340\/revisions"}],"predecessor-version":[{"id":3342,"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/posts\/3340\/revisions\/3342"}],"wp:attachment":[{"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/media?parent=3340"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/categories?post=3340"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sprocket-chain.net\/id\/wp-json\/wp\/v2\/tags?post=3340"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}