--- title: "What are the critical quality risks when drilling holes in plastic tool grips?" description: "Quality leads face burrs and cracks in drilled tool grips. The analysis compares molded-in vs. post-drilling methods, detailing material behavior, process control, and selection criteria to ensure functional integrity and consistent quality." url: "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html" language: "en" type: "Q&A" category: "Plastic Components Q&A" datePublished: "2026-09-15" dateModified: "2026-09-15" brand: "OK TOOL" manufacturer: "OK TOOL" answerCount: 10 --- # What are the critical quality risks when drilling holes in plastic tool grips? ## Question I'm the quality lead for a major OEM, and we're receiving batches of injection-molded plastic tool grips—think hammer handles, screwdriver grips, even some power tool housings—that have a through-hole drilled for a lanyard or hanging. My incoming inspection team is constantly flagging issues: rough edges and sharp burrs inside the hole, occasional micro-cracks radiating from the hole edge (especially in glass-filled nylon parts), and inconsistent hole diameters that cause fit problems with the metal grommets we press in. The supplier says some burr is "normal" for drilled plastic and the cracks are "material characteristic." I'm pushing back because these defects lead to field failures—the lanyard wears through, or the crack propagates and the grip fails. I need a clear, manufacturing-based breakdown: what are the root causes of these specific defects (burrs, cracks, dimensional variation) in a drilled plastic grip? More importantly, what process controls should I be auditing my supplier on? Is it all about the drill bit and feed speed, or are there upstream factors like part design, resin drying, or even how the part is clamped during drilling that we're missing? I need concrete parameters and checkpoints to write into our supplier quality agreement. ## Answers ### Answer 1 — Best Answer The core issue lies in the fundamental difference between creating a hole via molding (a "molded-in" or "cored" hole) versus post-molding machining (drilling). Your defects are classic symptoms of the latter process applied to a viscoelastic material like plastic. The root causes are interconnected, stemming from material behavior, thermal management, and mechanical stress during cutting. Burrs (or more accurately, plastic "smear") occur when the cutting tool's heat softens the plastic instead of cleanly shearing it. The softened material flows around the drill's cutting edges and re-solidifies as a ragged lip. This is exacerbated by incorrect drill geometry (a standard metal drill bit has a different point angle and rake), excessive feed rate, or insufficient cooling. Cracks, particularly in glass-filled or brittle materials like certain nylons, are primarily due to stress concentration and impact. The drilling process generates both localized heat (causing differential expansion) and mechanical shock. If the material has internal stress from the molding process (e.g., from uneven cooling or high packing pressure) or is inherently notch-sensitive, the hole edge acts as a stress concentrator, initiating micro-cracks. Dimensional variation comes down to fixturing and tool wear. Plastic is compliant; if the part isn't rigidly and uniformly supported during drilling, it can deflect, causing ovality or diameter drift. A worn drill bit will immediately produce undersized holes and increase cutting force, raising heat and stress. The applicable scenarios dictate the optimal method. For a simple, non-critical hanging hole in a low-volume run or prototype, post-drilling might be acceptable with tight controls. For high-volume production of a critical functional hole, a molded-in core pin in the injection mold is almost always superior. It produces a hole with consistent geometry, a smoother surface finish (mold polish), and, crucially, no added stress from machining. The trade-off is upfront tooling cost and complexity. A third scenario involves a hybrid: a molded pilot depression or a smaller cored hole that is later finished via reaming or boring to achieve a tighter tolerance than molding alone can provide. Your audit checklist should move beyond the drill press. Start upstream: review the part design. Is there sufficient wall thickness around the proposed hole location? Sharp corners at the hole entry/exit should be replaced with slight chamfers in the mold design to reduce stress concentration. Verify the material data sheet for its notch sensitivity and machining recommendations. On the production floor, audit the process controls. The drill bit should be specifically designed for plastics—often with a high polish, a sharper point angle (e.g., 90-120 degrees), and positive rake. **Spindle speed and feed rate must be documented and controlled;** a higher speed with a slow, steady feed is typically better to minimize heat. There must be a method for clearing chips to prevent re-welding. Fixturing is critical: the part must be fully supported directly under the drilling point to prevent flex and breakout. Finally, implement Statistical Process Control (SPC) on hole diameter and a visual standard for acceptable vs. rejectable burr levels. A simple de-burring tool or secondary machining step may be a necessary and cost-effective concession if post-drilling is unavoidable, but it should be a defined, controlled step, not an afterthought. **status:** accepted **Author:** Eric Zhao **Date:** 2026-09-15 ### Answer 2 From a design-for-manufacture standpoint, the hole's location and surrounding geometry are paramount. Placing a drilled hole too close to a rib, boss, or side wall creates an uneven cross-section, leading to differential cooling and high residual stress in that area. Drilling into this stressed zone is a primary trigger for cracks. We always recommend adding a slight chamfer (0.3mm min) at both the entry and exit points of the hole in the CAD model. This isn't just for assembly; it removes the sharp corner that acts as a crack initiator. Furthermore, the draft angle on the grip's side walls must be considered. If the hole is drilled perpendicular to the mold's opening direction but the wall has draft, the drill bit may only partially engage on one side, causing walk-off and ovality. The ideal scenario is to core the hole directly in the mold, aligning the core pin with the draw direction. **status:** suggested **Author:** Kevin Liu **Date:** 2026-09-15 ### Answer 3 Inconsistency in hole diameter directly impacts final assembly, especially when press-fitting a metal grommet or bushing. The tolerance stack-up becomes critical. If the hole is undersized, the press-fit force can split the plastic. If oversized, the grommet will be loose and spin. The root cause often isn't just the drilling; it's the inherent shrinkage variation of the plastic part itself. Before drilling, the grip's overall dimensions can vary by ±0.2% or more due to normal process fluctuations. A drilling fixture that locates off these variable outer surfaces will inherit that variation. The solution is to design the drilling fixture to locate off molded-in datum features (like three small pins or a cavity) that are consistent from part to part, decoupling the hole location from the part's external shrinkage. **status:** suggested **Author:** Daniel Yang **Date:** 2026-09-15 ### Answer 4 The resin grade selection fundamentally dictates the machinability of the grip. General-purpose ABS or polypropylene machines relatively cleanly. However, engineering grades like glass-filled nylon (PA6+GF) or PBT are notorious for abrasiveness and brittleness. The glass fibers are harder than the drill bit, causing rapid tool wear (leading to diameter variation) and often being torn out rather than cut, leaving a rough, crack-prone surface. For components requiring post-machining, we often recommend unfilled or mineral-filled versions of the same polymer family, as they offer a better balance of strength and machinability. If the glass fill is non-negotiable for strength, then switching to a molded-in hole becomes a cost-performance imperative, as the material cost saved by easier machining rarely offsets the quality risk and tooling expense. **status:** suggested **Author:** Linda Xu **Date:** 2026-09-15 ### Answer 5 Managing this issue requires clear phase-gate criteria. The sample approval stage is where the manufacturing method for the hole must be locked. If the initial prototypes use drilled holes, the production part approval process (PPAP) submission must include data from a capability study on the hole diameter and a validated de-burring process. Any change from drilled to molded-in after tooling kick-off is a major change order, impacting cost and timeline. The project plan must allocate time for a mold flow analysis to simulate cooling around the core pin, ensuring it doesn't create a sink mark or a short shot. The key milestone is the first article inspection from the production mold; the hole quality from the core pin must be verified before authorizing full mass production. **status:** suggested **Author:** Sophia Wang **Date:** 2026-09-15 ### Answer 6 For volume production, the consistency and cycle time of the drilling operation are line bottlenecks. A manual drilling station introduces human variability in feed pressure and part orientation. The solution is a dedicated, pneumatic or servo-driven drilling unit integrated into the production line, with automatic fixturing that presents the part in the same orientation every cycle. The drill bit's life must be monitored—a simple counter for cycles before replacement is essential. Furthermore, the drilling station should include an automated air blast to clear chips from the hole and fixture after each cycle. This prevents chip buildup from affecting part seating and ensures the next part is drilled cleanly, maintaining consistent quality across thousands of cycles. **status:** suggested **Author:** Michael Wu **Date:** 2026-09-15 ### Answer 7 The injection molding process parameters for the grip itself are a major upstream factor. High injection speed and packing pressure can induce significant molecular orientation and residual stress, particularly in the areas that will later be drilled. A part with low internal stress is far more resistant to cracking during machining. Therefore, the process window should be optimized for minimal stress, even if it means a slightly longer cycle time. Key parameters to review are melt temperature (too low increases viscosity and stress), packing pressure/time, and mold temperature. A higher mold temperature allows the plastic to relax more, reducing molded-in stress. A process capability (Cpk) study should be run on the molded parts' critical dimensions before they even reach the drilling station. **status:** suggested **Author:** David Zhang **Date:** 2026-09-15 ### Answer 8 Defining clear, measurable inspection criteria is the first step. "No burrs" is subjective; you need a go/no-go gauge or a defined maximum burr height (e.g., 0.1mm) measured with a depth gauge. Cracks should be classified: hairline cracks visible under 10x magnification might be acceptable for non-structural holes, but any crack visible to the naked eye is a critical defect. For dimensional checks, use plug gauges (Go/No-Go) for high-speed line inspection, supplemented with periodic CMM checks for true position and diameter. The inspection frequency (IQC, IPQC, OQC) should be based on the process capability index (Cpk) initially, moving to reduced frequency only after stability is proven. All inspection data should feed back to the drilling operator for real-time adjustment. **status:** suggested **Author:** Rachel Huang **Date:** 2026-09-15 ### Answer 9 If the hole is to be cored in the mold, the core pin design is critical. The pin must be made from hardened steel (like H13) and highly polished to ensure a smooth hole surface and easy ejection. Its length-to-diameter ratio must be considered; a long, thin core pin is prone to deflection under injection pressure, causing a tapered or misaligned hole. Adefficient cooling channel must run as close as possible to the core pin to solidify the plastic around it quickly, preventing drag marks and easing ejection. For high-volume runs, consider a replaceable core pin insert, so if wear occurs, only the insert is changed, not the entire mold plate, minimizing downtime and maintaining hole consistency over the mold's life. **status:** suggested **Author:** Olivia Chen **Date:** 2026-09-15 ### Answer 10 The ultimate validation is how the hole performs in the end-user's hands. A burr inside the hole will abrade and eventually cut through a fabric or plastic lanyard. A rough surface finish can harbor moisture and dirt in industrial environments. The functional requirement dictates the specification. If the hole is for a retention clip that sees frequent snap-in/snap-out action, the hole's edge must withstand repeated impact without cracking. This may necessitate a design change, such as adding a metal sleeve insert molded in place, which transforms the hole's function from a plastic feature to a metal bearing surface. The manufacturability analysis must start with these end-use loads and environmental exposures. **status:** suggested **Author:** Emily Chen **Date:** 2026-09-15 ## Related Resources - [Plastic Components Q&A](https://www.ok-tool.com/qa/plastic-components/) - [Plastic Components](https://www.ok-tool.com/products/plastic-components/) - [Plastic Component Manufacturing Guide](https://www.ok-tool.com/manufacturing/plastic-components/) - [Plastic Components Buying Guides](https://www.ok-tool.com/buying/plastic-components/) - [Capabilities](https://www.ok-tool.com/capabilities/) - [Custom Manufacturing](https://www.ok-tool.com/custom-manufacturing/) - [Manufacturing Knowledge Base](https://www.ok-tool.com/knowledge/) - [Plastic Components](https://www.ok-tool.com/knowledge/plastic-components/) ## Structured Data ```json [ { "@context": "https://schema.org", "@type": "QAPage", "mainEntity": { "@type": "Question", "name": "What are the critical quality risks when drilling holes in plastic tool grips?", "text": "I'm the quality lead for a major OEM, and we're receiving batches of injection-molded plastic tool grips—think hammer handles, screwdriver grips, even some power tool housings—that have a through-hole drilled for a lanyard or hanging. My incoming inspection team is constantly flagging issues: rough edges and sharp burrs inside the hole, occasional micro-cracks radiating from the hole edge (especially in glass-filled nylon parts), and inconsistent hole diameters that cause fit problems with the metal grommets we press in. The supplier says some burr is "normal" for drilled plastic and the cracks are "material characteristic." I'm pushing back because these defects lead to field failures—the lanyard wears through, or the crack propagates and the grip fails. I need a clear, manufacturing-based breakdown: what are the root causes of these specific defects (burrs, cracks, dimensional variation) in a drilled plastic grip? More importantly, what process controls should I be auditing my supplier on? Is it all about the drill bit and feed speed, or are there upstream factors like part design, resin drying, or even how the part is clamped during drilling that we're missing? I need concrete parameters and checkpoints to write into our supplier quality agreement.", "answerCount": 10, "upvoteCount": 5, "datePublished": "2026-09-15T12:45:35Z", "dateModified": "2026-09-15T13:07:54Z", "author": { "@type": "Person", "name": "Anonymous", "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html" } ,"acceptedAnswer": { "@type": "Answer", "text": "The core issue lies in the fundamental difference between creating a hole via molding (a "molded-in" or "cored" hole) versus post-molding machining (drilling). Your defects are classic symptoms of the latter process applied to a viscoelastic material like plastic. The root causes are interconnected, stemming from material behavior, thermal management, and mechanical stress during cutting. Burrs (or more accurately, plastic "smear") occur when the cutting tool's heat softens the plastic instead of cleanly shearing it. The softened material flows around the drill's cutting edges and re-solidifies as a ragged lip. This is exacerbated by incorrect drill geometry (a standard metal drill bit has a different point angle and rake), excessive feed rate, or insufficient cooling. Cracks, particularly in glass-filled or brittle materials like certain nylons, are primarily due to stress concentration and impact. The drilling process generates both localized heat (causing differential expansion) and mechanical shock. If the material has internal stress from the molding process (e.g., from uneven cooling or high packing pressure) or is inherently notch-sensitive, the hole edge acts as a stress concentrator, initiating micro-cracks. Dimensional variation comes down to fixturing and tool wear. Plastic is compliant; if the part isn't rigidly and uniformly supported during drilling, it can deflect, causing ovality or diameter drift. A worn drill bit will immediately produce undersized holes and increase cutting force, raising heat and stress. The applicable scenarios dictate the optimal method. For a simple, non-critical hanging hole in a low-volume run or prototype, post-drilling might be acceptable with tight controls. For high-volume production of a critical functional hole, a molded-in core pin in the injection mold is almost always superior. It produces a hole with consistent geometry, a smoother surface finish (mold polish), and, crucially, no added stress from machining. The trade-off is upfront tooling cost and complexity. A third scenario involves a hybrid: a molded pilot depression or a smaller cored hole that is later finished via reaming or boring to achieve a tighter tolerance than molding alone can provide. Your audit checklist should move beyond the drill press. Start upstream: review the part design. Is there sufficient wall thickness around the proposed hole location? Sharp corners at the hole entry/exit should be replaced with slight chamfers in the mold design to reduce stress concentration. Verify the material data sheet for its notch sensitivity and machining recommendations. On the production floor, audit the process controls. The drill bit should be specifically designed for plastics—often with a high polish, a sharper point angle (e.g., 90-120 degrees), and positive rake. Spindle speed and feed rate must be documented and controlled; a higher speed with a slow, steady feed is typically better to minimize heat. There must be a method for clearing chips to prevent re-welding. Fixturing is critical: the part must be fully supported directly under the drilling point to prevent flex and breakout. Finally, implement Statistical Process Control (SPC) on hole diameter and a visual standard for acceptable vs. rejectable burr levels. A simple de-burring tool or secondary machining step may be a necessary and cost-effective concession if post-drilling is unavoidable, but it should be a defined, controlled step, not an afterthought.", "upvoteCount": 5, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#acceptedAnswer", "datePublished": "2026-09-15T15:19:25Z", "author": {"@type": "Person","name": "Eric Zhao","url": "https://www.ok-tool.com/team/eric.html"} } ,"suggestedAnswer": [ { "@type": "Answer", "text": "From a design-for-manufacture standpoint, the hole's location and surrounding geometry are paramount. Placing a drilled hole too close to a rib, boss, or side wall creates an uneven cross-section, leading to differential cooling and high residual stress in that area. Drilling into this stressed zone is a primary trigger for cracks. We always recommend adding a slight chamfer (0.3mm min) at both the entry and exit points of the hole in the CAD model. This isn't just for assembly; it removes the sharp corner that acts as a crack initiator. Furthermore, the draft angle on the grip's side walls must be considered. If the hole is drilled perpendicular to the mold's opening direction but the wall has draft, the drill bit may only partially engage on one side, causing walk-off and ovality. The ideal scenario is to core the hole directly in the mold, aligning the core pin with the draw direction.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-2", "datePublished": "2026-09-15T15:05:04Z", "author": {"@type": "Person","name": "Kevin Liu","url": "https://www.ok-tool.com/team/kevin.html"} } , { "@type": "Answer", "text": "Inconsistency in hole diameter directly impacts final assembly, especially when press-fitting a metal grommet or bushing. The tolerance stack-up becomes critical. If the hole is undersized, the press-fit force can split the plastic. If oversized, the grommet will be loose and spin. The root cause often isn't just the drilling; it's the inherent shrinkage variation of the plastic part itself. Before drilling, the grip's overall dimensions can vary by ±0.2% or more due to normal process fluctuations. A drilling fixture that locates off these variable outer surfaces will inherit that variation. The solution is to design the drilling fixture to locate off molded-in datum features (like three small pins or a cavity) that are consistent from part to part, decoupling the hole location from the part's external shrinkage.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-3", "datePublished": "2026-09-15T14:54:30Z", "author": {"@type": "Person","name": "Daniel Yang","url": "https://www.ok-tool.com/team/daniel.html"} } , { "@type": "Answer", "text": "The resin grade selection fundamentally dictates the machinability of the grip. General-purpose ABS or polypropylene machines relatively cleanly. However, engineering grades like glass-filled nylon (PA6+GF) or PBT are notorious for abrasiveness and brittleness. The glass fibers are harder than the drill bit, causing rapid tool wear (leading to diameter variation) and often being torn out rather than cut, leaving a rough, crack-prone surface. For components requiring post-machining, we often recommend unfilled or mineral-filled versions of the same polymer family, as they offer a better balance of strength and machinability. If the glass fill is non-negotiable for strength, then switching to a molded-in hole becomes a cost-performance imperative, as the material cost saved by easier machining rarely offsets the quality risk and tooling expense.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-4", "datePublished": "2026-09-15T14:17:54Z", "author": {"@type": "Person","name": "Linda Xu","url": "https://www.ok-tool.com/team/linda.html"} } , { "@type": "Answer", "text": "Managing this issue requires clear phase-gate criteria. The sample approval stage is where the manufacturing method for the hole must be locked. If the initial prototypes use drilled holes, the production part approval process (PPAP) submission must include data from a capability study on the hole diameter and a validated de-burring process. Any change from drilled to molded-in after tooling kick-off is a major change order, impacting cost and timeline. The project plan must allocate time for a mold flow analysis to simulate cooling around the core pin, ensuring it doesn't create a sink mark or a short shot. The key milestone is the first article inspection from the production mold; the hole quality from the core pin must be verified before authorizing full mass production.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-5", "datePublished": "2026-09-15T14:15:19Z", "author": {"@type": "Person","name": "Sophia Wang","url": "https://www.ok-tool.com/team/sophia.html"} } , { "@type": "Answer", "text": "For volume production, the consistency and cycle time of the drilling operation are line bottlenecks. A manual drilling station introduces human variability in feed pressure and part orientation. The solution is a dedicated, pneumatic or servo-driven drilling unit integrated into the production line, with automatic fixturing that presents the part in the same orientation every cycle. The drill bit's life must be monitored—a simple counter for cycles before replacement is essential. Furthermore, the drilling station should include an automated air blast to clear chips from the hole and fixture after each cycle. This prevents chip buildup from affecting part seating and ensures the next part is drilled cleanly, maintaining consistent quality across thousands of cycles.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-6", "datePublished": "2026-09-15T14:14:30Z", "author": {"@type": "Person","name": "Michael Wu","url": "https://www.ok-tool.com/team/michael.html"} } , { "@type": "Answer", "text": "The injection molding process parameters for the grip itself are a major upstream factor. High injection speed and packing pressure can induce significant molecular orientation and residual stress, particularly in the areas that will later be drilled. A part with low internal stress is far more resistant to cracking during machining. Therefore, the process window should be optimized for minimal stress, even if it means a slightly longer cycle time. Key parameters to review are melt temperature (too low increases viscosity and stress), packing pressure/time, and mold temperature. A higher mold temperature allows the plastic to relax more, reducing molded-in stress. A process capability (Cpk) study should be run on the molded parts' critical dimensions before they even reach the drilling station.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-7", "datePublished": "2026-09-15T13:59:29Z", "author": {"@type": "Person","name": "David Zhang","url": "https://www.ok-tool.com/team/david.html"} } , { "@type": "Answer", "text": "Defining clear, measurable inspection criteria is the first step. "No burrs" is subjective; you need a go/no-go gauge or a defined maximum burr height (e.g., 0.1mm) measured with a depth gauge. Cracks should be classified: hairline cracks visible under 10x magnification might be acceptable for non-structural holes, but any crack visible to the naked eye is a critical defect. For dimensional checks, use plug gauges (Go/No-Go) for high-speed line inspection, supplemented with periodic CMM checks for true position and diameter. The inspection frequency (IQC, IPQC, OQC) should be based on the process capability index (Cpk) initially, moving to reduced frequency only after stability is proven. All inspection data should feed back to the drilling operator for real-time adjustment.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-8", "datePublished": "2026-09-15T13:49:56Z", "author": {"@type": "Person","name": "Rachel Huang","url": "https://www.ok-tool.com/team/rachel.html"} } , { "@type": "Answer", "text": "If the hole is to be cored in the mold, the core pin design is critical. The pin must be made from hardened steel (like H13) and highly polished to ensure a smooth hole surface and easy ejection. Its length-to-diameter ratio must be considered; a long, thin core pin is prone to deflection under injection pressure, causing a tapered or misaligned hole. Adefficient cooling channel must run as close as possible to the core pin to solidify the plastic around it quickly, preventing drag marks and easing ejection. For high-volume runs, consider a replaceable core pin insert, so if wear occurs, only the insert is changed, not the entire mold plate, minimizing downtime and maintaining hole consistency over the mold's life.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-9", "datePublished": "2026-09-15T13:19:45Z", "author": {"@type": "Person","name": "Olivia Chen","url": "https://www.ok-tool.com/team/olivia.html"} } , { "@type": "Answer", "text": "The ultimate validation is how the hole performs in the end-user's hands. A burr inside the hole will abrade and eventually cut through a fabric or plastic lanyard. A rough surface finish can harbor moisture and dirt in industrial environments. The functional requirement dictates the specification. If the hole is for a retention clip that sees frequent snap-in/snap-out action, the hole's edge must withstand repeated impact without cracking. This may necessitate a design change, such as adding a metal sleeve insert molded in place, which transforms the hole's function from a plastic feature to a metal bearing surface. The manufacturability analysis must start with these end-use loads and environmental exposures.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/quality-risks-drilling-plastic-tool-grips.html#suggestedAnswer-10", "datePublished": "2026-09-15T13:07:54Z", "author": {"@type": "Person","name": "Emily Chen","url": "https://www.ok-tool.com/team/emily.html"} } ] } }, { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ {"@type": "ListItem", "position": 1, "name": "Home", "item": "https://www.ok-tool.com/"},{"@type": "ListItem", "position": 2, "name": "Q&A", "item": "https://www.ok-tool.com/qa/"},{"@type": "ListItem", "position": 3, "name": "Plastic Components Q&A >", "item": "https://www.ok-tool.com/qa/plastic-components/>"} ,{"@type": "ListItem", "position": 4, "name": "What are the critical quality risks when drilling holes in plastic tool grips?"} ] } ] ```