Find the Optimal Round Tensile Sample Preparation Equipment
Struggling with effective round tensile sample preparation? Round tensile test specimen preparation is made easy with our line up of easy-to-use, fast and precise lathes for round tensile preparation. Turning round, square or irregular stock is no problem for these robust round tensile sample preparation machines. Each CNC for round sample preparation comes standard with user-friendly software and other components for your long-term operational needs. Our lathes are designated CNC for round tensile specimen preparation, however can also be used for standard CNC machining needs. Make your round tensile sample preparation the easiest part of your day with TensileMill's line up equipment.
TensileTurn CNC – Industrial Upgrade – Round Tensile Sample Preparation Machine
The Industrial Upgrade model is a substantial step up from our Classic system. It offers the ability to accommodate larger starting blank sizes, tougher materials, irregular shapes, higher specimen preparation volumes, automatic center drilling and other unique functions required for the simplest and most accurate round tensile sample preparation. This system comes standard with a granite frame for added stability and the shock absorption for maximum sample preparation accuracy and longer system life-span. Though the Industrial Upgrade system is extraordinary for tensile specimen preparation needs, it is also capable of full range of CNC machining capabilities.
TensileTurn CNC - Classic Upgrade - Round Tensile Specimen Preparation Machine
This classic tensile sample preparation machine is designed to accommodate round tensile specimen requirements from both round and square stocks as well as other CNC machining requirements. The standard tensile software included with the unit allows for round tensile milling results in seconds with a push of a button. This industrial, user-friendly machine can accommodate medium to large volume of daily round tensile or other round CNC requirements. TensileTurn CNC is an ideal solution for medium to larger size laboratories and manufacturing facilities.
TensileTurn CNC XL - Heavy Duty Round Specimen Preparation
TensileTurn CNC XL is the upgraded version of our TensileTurn CNC classic unit. This powerful lathe is capable of turning round, square and irregular stock of tougher materials in the marketplace. The machine comes equipped with a robust tooling fixture, precision tailstock, and a high powered spindle. TensileTurn CNC XL is no doubt the ultimate round tensile test sample preparation machine capable of both tensile specimen preparation and advanced CNC machining. The unit is capable of meeting high capacity and high quantity output requirements for medium to large size laboratories and manufacturing facilities.
Will burrs remain on tensile specimens after the cutting cycle on a TensileMill CNC sample preparation system?
Edge condition after machining depends on material type, cutter or insert condition, feed and speed, coolant, and toolpath strategy. With the supplied starter tooling and tuned parameters, burr can typically be minimized to a negligible edge or eliminated. Good practices include matching the cutter or insert grade to the alloy, keeping cutting edges sharp, using adequate coolant, and programming climb milling with a light finishing pass of about 0.005 to 0.010 in (0.13 to 0.25 mm) stock. Adding a small edge break of roughly 0.005 in (0.13 mm) with a chamfer or deburr pass helps reduce handling nicks before testing.
If some burr remains, quick secondary methods are common in tensile labs: hand files, deburring blades, small countersinks, tube deburring tools for round gage sections, fine flap wheels, and nonwoven abrasive pads. Remove only the raised edge so gage width or diameter is not altered, then verify dimensions and surface quality prior to testing. Our team can recommend tooling and parameters for both flat and round workflows to help you hit your required finish with minimal rework.
If you would like to source deburring media, end mills, inserts, and related supplies, you can review options on the Consumables and Spare Parts page.
How do I determine the optimal spindle speed and feed rate for machining tensile specimens in a specific material?
Optimal speed and feed depend on the material, cutter geometry, coating, and the specimen’s gauge geometry. Start with tooling matched to your alloy or polymer, then validate with a brief trial. TensileMill CNC offers complimentary dog-bone preparation where our engineers cut your samples on flat and round specimen systems such as the TensileMill CNC MICRO or MINI for flat blanks and the TensileTurn CNC series for round bars, typically converging on stable parameters by the second or third cycle. During installation and training, our technicians also tune speeds, feeds, coolant strategy, and toolpaths at your site so production runs are repeatable and surface finish in the gauge section aligns with your testing needs.
A practical workflow is to begin with the cutter manufacturer’s conservative chip load, a shallow axial depth per pass such as 0.050 to 0.100 in (1.27 to 2.54 mm), and moderate radial engagement. Make a short 1 to 2 in (25 to 50 mm) test pass outside the gauge length, then review chip form, temperature at the gauge, spindle load, and finish. Increase feed in small steps until chatter or rising load appears, reduce by about 10 percent, and adjust rpm to stabilize the cut. Use climb milling for flat specimens, sharp inserts on round specimens, and flood coolant or MQL to keep the gauge section smooth, which supports ASTM E8 or ASTM D638 geometry requirements when applicable. Save the final recipe in the controller for repeatable throughput.
If you would like parameter guidance for your material or a complimentary dog-bone trial, you can connect with our team on the Contact Us page.
What Additional Maintenance Steps Extend the Life of a Tensile Sample Preparation Machine?
Routine preventive maintenance and a clean workspace go a long way. Keep the lubrication reservoir topped with the recommended oil, wipe down exposed surfaces, and remove chips after each shift to reduce wear on moving components and guarding.
For daily care, vacuum chips instead of blowing them into seals, clear the chip tray, and dry any coolant residue on the table, vises, and fixtures. Confirm that the automatic lubrication system is cycling and that lines are intact. Inspect the spindle taper and tool holders for debris, then lightly clean and re-seat them to protect runout. Keep the coolant or mist system clean by using approved fluids and replacing filters as needed. Periodically check way covers, door interlocks, cable carriers, and the condition of belts, fasteners, and guarding. Verify that the air supply is clean and dry to protect valves and actuators. Back up machine parameters and software, and record service actions in a simple log so you can spot trends. Train operators to run a brief warmup program at start of day, handle specimens and tooling carefully, and report any unusual noise, heat, or vibration immediately.
If you would like maintenance guidance tailored to your setup or a recommended service interval, you can connect with our team on the Contact Us page.
What Are Fundamental Maintenance Tips to Extend the Life of a Round Tensile Sample Preparation Machine?
Routine care keeps your round specimen lathe reliable and accurate. Keep the enclosure, ways, and spindle nose free of chips and abrasive dust after each shift. Use a vacuum or soft brush rather than open air blasts to protect seals. Check coolant level and concentration, way lubrication, and any hydraulic or pneumatic reservoirs at startup, then top off with the recommended fluids. Clean or replace coolant and air filters regularly, and skim tramp oil to keep the mix healthy. Back up your programs, offsets, and TensileSoft or Carbon settings whenever you make changes.
Inspect chuck jaws, collets, and tailstock quill for wear and burrs, and verify smooth clamping and release. Replace dull inserts early to protect surface finish and diameter control on gage sections used for ASTM E8 or ISO 6892 specimens. Watch for unusual vibration, heat, or noise, then address alignment or tooling issues before they affect tolerances. Periodically verify spindle runout and tailstock alignment with a test bar, and confirm turret indexing accuracy. If the machine sits idle, run a warm-up cycle to circulate lubrication and prevent corrosion. Keeping the system clean, lubricated, and exercised reduces downtime and extends service life.
If you would like additional care practices and model options for round specimen lathes, you may explore recommendations on the Round Tensile Sample Preparation Machines page.
What Installation and Training Options Does TensileMill CNC Provide?
We offer a standard 1-day onsite installation and operator training program for new systems. For lathe-based round specimen preparation, most teams schedule a full day so operators become proficient with setup, TensileSoft programming, and safe machining practices for ASTM E8 or ISO 6892 work.
The session covers machine placement and power-up, leveling and verification, chucking and soft-jaw use, tooling selection, parameter libraries for common alloys, toolpath creation in TensileSoft, first-article runs, gauge length transitions, surface finish targets in the reduced section, and routine maintenance. Experienced CNC machinists often opt for a remote commissioning session by web conference or phone, supported by step-by-step training videos for pre-assessment and refresher use. Remote support is also practical for onboarding new operators after the initial install. Scheduling can be adapted for a single operator or multiple shifts, and follow-up Q&A is available to tune cycle times and part quality for your throughput requirements.
If you are planning a lathe-based setup, you may review system options and training availability on the Round Tensile Test Sample Preparation Machines page.
How Easy Is the TensileTurn CNC for Operators With Limited CNC Lathe Experience?
The system is approachable for new users. Operators should have basic lathe safety and workholding knowledge to avoid mistakes. A minimum of 1 day of onboarding is typically sufficient for teams to progress from blank setup to producing repeatable round tensile specimens.
During training, your team uses the tensile interface on the Carbon Mach4 controller. You can select a template from the built-in library for common standards such as ASTM E8 and ISO 6892-1, or enter custom dimensions for your program. The workflow covers preparing round, square, or irregular starting blanks, setting chuck jaws and tailstock support, touching off tools, and running the guided roughing and finishing cycles. Operators practice saving recipes so future batches follow the same parameters for consistent results across shifts. On some models, features like automatic center drilling help with alignment and throughput. After this session, non-programmers typically load a blank, choose or edit a template, and start the cut with only a few prompts.
If you would like to review models, training recommendations, and software workflow, you can read more on the TensileTurn CNC – Round Specimen Preparation page.
Is TensileTurn CNC Easy To Operate, And Do You Offer Operator Training?
TensileTurn CNC is designed for fast adoption in quality labs and production environments. Operators can select a round specimen template aligned with common standards such as ASTM E8 or ISO 6892, or enter custom diameter and gauge length on the touchscreen. The purpose-built interface guides tool selection, work offsets, feeds, and cut passes, then creates the machining sequence for consistent results. New users can prepare accurate specimens after a brief orientation, while experienced machinists can access full turning functions for threading, facing, and specialty geometries.
Every system includes tailored onboarding delivered remotely or on site based on your workflow. Training covers software navigation, setup, fixturing and workholding, tooling best practices, safety procedures, and dimensional verification of critical features like gauge section, transition radii, and surface finish for tensile testing.
For ongoing help, our technical team is available by phone at 877-672-2622 ext. 3, by email at support1@tensilemillcnc.com, or through our online ticketing system. You also receive continued access to software updates and application guidance to keep specimen preparation consistent across shifts.
If you would like to compare models and software workflows, you can read more on the Round Tensile Test Sample Preparation Machines page.
How Are Center Holes Added to Round Tensile Specimen Blanks Before Turning?
Center holes are typically produced as a separate operation on a drill press using a simple locating fixture. Our round tensile specimen lathes do not automate the center-drilling step.
Some shops also create the centers directly in the lathe using a center drill or spotting drill held in the tailstock. With the blank secured and the spindle at low speed, the operator feeds the tool to form a 60 degree center on one end, repeats on the opposite end, then proceeds to rough and finish turn between centers or with a live center. This in-lathe approach can reduce handling time and maintain concentricity, yet it is an advanced method that should be performed only by an experienced machinist because the work is completed with the spindle running and tool clearances are tight. For repeatable batch work and straightforward fixturing, many labs prefer a dedicated drill press station for the centers, then move directly to turning on the lathe.
If you would like to compare workflow options for center drilling and turning, you can read more about available lathes on the Round Tensile Sample Preparation Machines page.
Can We Purchase the Round Tensile Specimen Preparation Lathe Used to Machine Our Samples?
Yes. We regularly make our in-house round tensile specimen lathes available as demo units for purchase. If you would like the exact machine that produced your samples, mention this when you submit blanks or when you request a quote. Our CNC consultants will coordinate with the production team to run your job on a saleable unit and reserve that lathe under your purchase order.
After you confirm, we will coordinate configuration, software profiles, and any required workholding or tooling so the machine ships prepared for your material and geometry needs. Accessories such as chucks, collets, toolholders, and consumables can be quoted with the system, and shipping will be scheduled around your lab timeline. If you prefer a brand-new build with matching capability, that option can be quoted as well while a demo machine continues to support sample services.
If you would like to compare round specimen lathe options or review configurations, you may explore details on the TensileTurn CNC - Round Specimen Preparation page.
What Straightness Tolerance Should Starting Blanks Meet for the Round Tensile Specimen Lathe?
Target starting blanks that are straight within 0.005 in (0.13 mm) across the working length. Straighter stock promotes accurate cuts, safer clamping, and consistent gauge sections on round tensile specimens.
Verify straightness by indicating the blank between centers and checking total indicator runout at several locations along the length. If readings exceed 0.005 in (0.13 mm), correct the condition by straightening, shortening the working span, or taking a light skim cut to true the surface before final passes. Prepare both ends with clean center drills, select grips or collets that match the diameter, and, for material with slight bow, use a steady or follower rest to stabilize the cut. Replace bars that remain out of tolerance, since excessive bow increases runout, chatter, taper, and tool wear, and it can compromise final specimen geometry and surface finish needed for downstream polishing and testing.
If you would like additional setup tips and model options for round specimen turning, you can explore the lineup on the Round Tensile Test Sample Preparation Machines page.
What Is the Most Cost-Effective Machine for Fast Round Tensile Specimen Machining?
For cost-sensitive labs that still need speed, the best fit is our TensileTurn CNC family for round tensile samples. These lathe-based systems deliver fast, repeatable specimen production with modest consumable use and straightforward operator workflows. The Classic Upgrade is a strong value for routine daily prep, the Industrial Upgrade supports higher throughput with more robust hardware and automation options, and the XL model handles larger diameters and longer work envelopes.
To match a configuration to your application, share your blank stock size, target specimen geometry, material type with hardness values, surface finish goals, relevant standards such as ASTM E8 or ISO 6892, and expected specimens per shift. With that information, our specialists select workholding, insert grades, programmable fillet radii, and cycle templates that reduce setup and cut time while maintaining dimensional repeatability. Quick-change tooling and intuitive controls help new and experienced operators produce standard-compliant parts with minimal training.
If you would like to compare models and review options, you can explore the Round Tensile Test Sample Preparation Machines page for details on specifications and workflows.
Can the TensileTurn CNC Machine Prepare Round Tensile Specimens Directly From Pipe?
Yes. The TensileTurn CNC lineup can machine round tensile specimens directly from pipe sections using purpose-built workholding. Custom jaws, expanding mandrels, or soft inserts clamp on the outer diameter or inner diameter to keep the blank concentric for standards-based geometries such as ASTM E8 when dimensions permit.
After you load a cut pipe segment, the fixture secures the piece and a steady rest or tailstock supports the span. The programmed cycle rough-turns and finish-turns the gauge section, cuts shoulder radii, faces ends, and parts off in one setup to minimize runout and heat. For thin-wall material, sacrificial mandrels or internal supports help prevent collapse, and conservative feeds with sharp tooling reduce chatter. Fixturing can be tailored for short coupons or longer sections, with options for ID- or OD-driven clamping based on wall thickness and diameter. Before we quote tooling, we typically confirm pipe OD, ID, wall thickness, section length, target gauge diameter and length, and material so the machine produces specimens that match your method.
If you would like to compare models and workholding options, you can explore configurations on the Round Tensile Test Sample Preparation Machines page.
What Is the Optimal Solution for Fast Round Tensile Specimen Preparation?
The TensileTurn CNC series provides a rapid, repeatable path to machine round tensile specimens in-house. These lathe-based systems pair dedicated tensile software with purpose-built fixturing to move operators from raw stock to a finished specimen in minutes.
Operators can load round, square, or irregular blanks, select a preloaded geometry aligned with common standards such as ASTM E8 or ISO 6892, or enter custom dimensions, then start the cycle. The control interface streamlines toolpaths for turning, facing, center drilling, and threading, so labs without full-time machinists can achieve consistent gauge diameters and smooth transitions. Optional accessories, including a 4-jaw chuck for square stock and quick-change tooling, support stable clamping and fast setups for diverse materials and part shapes. Dedicated tensile tooling packages and application templates help maintain dimensional repeatability and surface finish that supports accurate test results.
By moving specimen preparation off busy production machines and into a focused TensileTurn workflow, quality teams increase throughput, reduce outsourcing delays, and keep testing on schedule.
If you would like to compare models and software options, you can review details on the Round Tensile Test Sample Preparation Machines page.
Where Is the Control System for the TensileTurn CNC Round Tensile Machine Manufactured?
Our round tensile specimen preparation machines use a North American control platform. The controls hardware and operator interface are sourced from North American partners, then integrated, assembled, and tested at TensileMill CNC facilities in the United States and Canada.
This domestic origin supports rapid technical assistance, readily available service parts, and ongoing software updates for both production and laboratory environments. The control package arrives preloaded with our tensile interface for quick job setup, and compatible models include our Carbon Mach4 environment for advanced CNC functions. With regional supply and assembly, you get consistent performance, responsive support, and long-term maintainability across your round specimen preparation workflow.
If you would like to compare controller options and machine formats, you can read more on the Round Tensile Test Sample Preparation Machines page.
Can TensileTurn CNC Prepare Round Specimens to ASTM E9?
Yes. The TensileTurn CNC family supports round specimen preparation aligned with ASTM E9 through its integrated tensile software. Operators select ASTM, choose ASTM E9, verify the programmed geometry, then start the cycle for a guided, repeatable workflow.
In practice, you mount the blank in a chuck or collet with tailstock support, set tool offsets, and load the E9 template. The program executes rough and finish passes, blends shoulders, and applies edge-break routines to deliver consistent geometry ready for downstream testing. Supervisors may lock feeds, speeds, and dimension fields to protect your validated method, while operators run production using saved templates for batch work. Compatible tooling kits and coolant strategies help maintain stable chip control and surface finish, and the software allows controlled adjustments when a lab method requires specific diameter transitions or relief features. This approach reduces setup time, supports traceable repeatability, and helps new users produce standard-compliant parts with minimal training.
If you would like to review configurations and software workflows for round specimen machining, you can explore details on the Round Tensile Test Sample Preparation Machines page.
What Standards Besides ASTM E8 Does TensileTurn CNC Support for Round Tensile Specimen Preparation?
Yes. The TensileTurn CNC includes a built-in library covering common round-specimen geometries from ISO, DIN, and JIS standards in addition to ASTM E8. Operators can also create, edit, or remove templates, so the system adapts to lab methods, customer prints, or legacy procedures.
From the touchscreen, you select a standard family, then choose a geometry or input parameters such as reduced-section diameter, gauge length, shoulder diameter, and fillet radius. Entries can be saved as reusable templates and updated later as requirements change, including ISO 6892-1 style layouts when applicable. The software applies appropriate toolpaths and lets you store material-specific cutting recipes for repeatable throughput. Updates delivered by TensileMill CNC add new options over time, keeping the library current without disrupting production. Beyond standardized shapes, the same platform runs as a CNC lathe for non-standard tensile blanks and auxiliary round features, helping labs and production teams keep specimen preparation in house and on schedule.
If you would like to compare models or browse compatible standards, you can review the details on the Round Tensile Sample Preparation Machines page.
What Consumables Are Available for TensileTurn CNC Round Specimen Preparation Machines?
TensileTurn CNC machines rely on a concise set of consumables for round specimen preparation. Each system ships with material-specific holders and matched cutting inserts, which serve as the primary wear items for ongoing operation.
Holders are durable tooling that typically provide multi-year service when kept clean, aligned, and free of crash loads. Inserts are designed for regular replacement. Their life varies with material hardness, feed and speed selection, coolant application, and total run time. Many labs keep insert styles dedicated to aluminum, steels, and nickel-based alloys to maintain predictable finish and geometry.
Routine shop fluids are also part of normal use. A water-soluble coolant supports chip evacuation and heat control, and machine lubrication is consumed through periodic maintenance. While these fluids are not replaced as frequently as inserts, planning them as consumables helps sustain throughput without interruptions.
For uninterrupted production, consider stocking spare insert packs for your most common materials and maintaining backup holders if you change materials often or run multiple shifts.
If you would like to compare insert options or plan a spare tooling kit, you can review available items on the Consumables and Spare Parts page.
Is In-House Tensile Specimen Preparation More Cost-Effective Than Outsourcing?
For labs with steady testing, in-house preparation typically reduces total cost after the initial equipment purchase, because the marginal cost per specimen becomes far lower than paying per batch externally. For occasional or sporadic testing, outsourcing can be practical since there is no upfront capital spend.
Outsourcing carries variable charges that repeat with every order: setup and machining fees, packaging, two-way shipping, potential rush charges, and idle time while parts are in transit. Those costs scale directly with demand and can rise with tighter tolerances or special profiles for standards such as ASTM E8 or ISO 527. If rework is needed, the cycle repeats.
In-house shifts spending to a fixed asset plus predictable items like cutters, inserts, coolant, and routine maintenance, along with operator time. Once a flat or round specimen system is installed, the next sample mainly reflects tool wear and minutes of machine time, and adjustments happen immediately without courier delays. Facilities running regular production checks, R&D iterations, or academic coursework usually see per-specimen cost drop as throughput increases, especially when using batch cycles or multi-part fixtures to machine multiple blanks in one run.
If you would like to discuss throughput, staffing, and payback for your lab, you can connect with our team on the Contact Us page.
How Do I Choose Between Flat and Round Tensile Specimen Preparation Systems?
Start with your material form and the target geometry required by your test method. Flat preparation is ideal for sheet, plate, or molded panels, commonly used for ASTM E8 metals or ISO 527 plastics. Typical flat dog-bone sizes include 0.25 to 1.00 in (6 to 25 mm) gauge width with 1.00 to 2.00 in (25 to 50 mm) gauge length and 0.125 in (3.2 mm) fillet radii. Round preparation suits bar, rod, wire, or cast buttons, with frequent sizes of 0.250 to 0.500 in (6 to 13 mm) diameter and 2.00 to 4.00 in (50 to 100 mm) gauge length. Target tolerances often hold ±0.001 in (±0.025 mm) in the gauge section and 0.001 in TIR (0.025 mm) concentricity for round specimens.
Consider throughput and handling. For high coupon volumes across multiple alloys, a fixtured flat CNC system supports repeatable nesting and quick changeovers. For rounds, a programmable lathe-style machine with tailstock support and center drilling maintains straightness on longer pieces, for example 6 to 12 in (152 to 305 mm) overall length, while flood or mist coolant protects both metals and polymers.
Confirm UTM and grip compatibility early. Flats pair well with wedge or pneumatic grips using 1 to 2 in (25 to 50 mm) jaw widths. Rounds may require collets, shoulders, or threaded ends such as 0.500-20 UNF, with shoulder perpendicularity within 0.002 in (0.05 mm). Surface finish affects results, so polish the gauge section longitudinally to Ra ≤ 32 µin (0.8 µm), or to 16 µin (0.4 µm) for notch-sensitive materials, and verify dimensions against the selected standard during first-article inspection.
If you are comparing flat and round preparation solutions, you can explore the TensileMill CNC Homepage to review product families on the page.
How Do I Choose Between Flat and Round Tensile Specimen Preparation Systems?
Selection depends on your product form, the governing standard, and downstream gripping. For sheet, plate, and extrusions, a milling-based system produces flat coupons to ASTM E8/E8M or ISO 6892-1 for metals, and ASTM D638 or ISO 527 for polymers. For bar, rod, and forged stock, a lathe-style system machines round specimens, typically 0.500 in (12.5 mm) nominal diameter with 2.00 in (50 mm) gauge length for ASTM E8, or subsize options when thickness limits the section.
Consider precision and finish. Flat machining supports tight edge tolerance around ±0.001 in (±0.025 mm) and surface finish near 32 µin Ra (0.8 µm) when tooling is sharp. Turning round specimens makes concentricity and straightness easier to control, often within 0.001 in (0.025 mm) TIR, which reduces bending errors. If your lab needs a mirror finish for strain extensometers, plan on a polishing pass to achieve 16 µin Ra (0.4 µm) or better.
Throughput and fixturing also matter. Flat systems can fixture multiple blanks per cycle, which is efficient for sheet from 0.020 to 0.250 in (0.5 to 6.0 mm) thickness. Round systems suit continuous runs from 0.125 to 1.000 in (3.2 to 25.4 mm) diameter bar. Verify your UTM grip style, wedge grips for flat widths like 0.500 in (12.5 mm) or collet or threaded holders for round shoulders, and confirm overall length, for example 6.0 to 10.0 in (152 to 254 mm), matches the machine and standard.
For additional guidance, you can connect with our team on the Contact Us page.
How Do I Machine Round Tensile Specimens to ASTM E8 and ISO 6892-1 Requirements?
Select geometry that matches your test method and grips. Common round specimens use a 0.505 in (12.83 mm) gauge diameter with a 2.000 in (50.80 mm) gauge length for ASTM E8 work. ISO workflows often use a 0.492 in (12.50 mm) diameter with a 1.969 in (50.00 mm) gauge length. Subsize options such as 0.250 in (6.35 mm) diameter with a 1.000 in (25.40 mm) gauge length are also typical. Face and center drill both ends, then run between centers. When unsupported length exceeds 6.0 in (152.4 mm), add a steady rest or follower.
Rough turn leaving 0.005 to 0.010 in (0.13 to 0.25 mm) per side for finishing. Make the finish pass in one continuous move across the entire gauge length. Target a diameter tolerance of ±0.0005 in (±0.013 mm) and roundness within 0.0003 in (0.008 mm). Keep the gauge section concentric to the centers within 0.0010 in (0.025 mm). Aim for a surface finish of 32 µin Ra (0.80 µm) or better. Use collets or soft jaws for grip sections, support the free end with a live center, and avoid interrupted cuts that could score the gauge.
Blend into the grip shoulders with smooth radii, for example 0.10 to 0.25 in (2.5 to 6.0 mm), to minimize stress concentrations in line with ASTM E8 and ISO 6892-1 intent. If polishing is specified, use longitudinal polishing on the gauge only. Verify final size at multiple locations every 0.25 in (6.35 mm), record the measurement traceability, and mark the gauge ends 2.000 in (50.80 mm) apart before testing.
For model capabilities, automation options, and footprints, you can review details on the All Round Sample Preparation Products page.
What Surface Finish And Runout Should Round Tensile Specimens Meet For ASTM E8 And ISO 6892?
For metallic round specimens, laboratories commonly target a gage-section finish of Ra at or below 32 µin (0.8 µm). For high-strength or notch-sensitive alloys, many facilities work to Ra at or below 16 µin (0.4 µm). Total indicator runout measured at the gage section while supported between centers should be at or below 0.001 in (0.025 mm) to minimize unintended bending. Follow ASTM E8 and ISO 6892 drawing requirements for gage length and shoulder transitions, and avoid circumferential tool marks in the reduced section.
On a TensileTurn system, mount blanks between a precision chuck and live tailstock center, then rough and finish in stages. Use a light final depth of cut of about 0.002 to 0.006 in (0.05 to 0.15 mm) with a small nose-radius insert and a 0.002 to 0.006 in/rev (0.05 to 0.15 mm/rev) feed to stabilize chip load and preserve surface integrity. Verify coaxiality by indicating the turned gage while still between centers, and adjust offsets until TIR meets the target.
Break all edges with a 0.010 to 0.020 in (0.25 to 0.50 mm) chamfer and polish axially through 320 to 600 grit, finishing only in the gage length, until the required Ra is achieved. Confirm diameter within ±0.0005 in (±0.013 mm) and gage length within ±0.005 in (±0.13 mm), or tighter if your method requires it. For elevated-temperature tests, review ASTM E21 or ISO 6892-2 before machining to confirm any additional geometry notes.
If you are comparing round-specimen machining options, you can explore model capabilities on the All Round Sample Preparation Products page.
How Do Round Tensile Specimen Machines Maintain Gauge Accuracy And Surface Finish?
Precision round-specimen equipment controls runout, rigidity, and toolpath geometry. A collet or well-trued 3-jaw chuck with live-center tailstock support typically keeps total indicated runout at or below 0.0005 in (0.013 mm). Constant surface speed, stable part overhang under 2.5–3.0 in (64–76 mm) past the jaws when possible, and balanced tooling reduce vibration that can imprint taper or chatter on the gauge section.
Most labs rough to near-net size, then finish in one continuous pass. A common approach is to leave 0.010–0.020 in (0.25–0.50 mm) of stock, apply a finish depth of cut of 0.005–0.010 in (0.13–0.25 mm), and feed 0.002–0.006 in/rev (0.05–0.15 mm/rev) with a sharp nose radius that blends into the fillets. Measure at multiple locations along the gauge, typically every 0.50 in (13 mm), and adjust tool-wear compensation in 0.0001 in (0.0025 mm) steps until taper across the gauge length is ≤0.001 in over 2.00 in (≤0.025 mm over 50 mm).
For metals tested to ASTM E8 or ISO 6892-1, many labs target a finish of ≤32 µin Ra (≤0.8 µm Ra) to minimize stress risers, with ≤16 µin Ra (≤0.4 µm Ra) when high-strength alloys or fracture-critical studies are involved. If turning alone does not achieve the desired roughness, follow with longitudinal polishing to refine the gauge without changing diameter. Verify final gauge length, such as 2.00 in (50 mm) or 5D as specified, and ensure smooth fillet transitions, free of tool marks, before moving the specimen to the UTM.
If you would like to compare lathe-based solutions, you can explore capabilities and options on the All Round Sample Preparation Products page.
What Surface Finish And Dimensional Tolerances Are Recommended For Round Tensile Specimens?
For metals tested to ASTM E8/E8M or ISO 6892-1, labs typically target a fine, uniform finish on the gage section to minimize stress raisers. A practical target is 32 µin Ra (0.8 µm) or better. For high-strength alloys or if repeatability is critical, aim for 16 µin Ra (0.4 µm). Always machine and polish longitudinally, never circumferentially.
Hold diameter within ±0.0005 in (±0.013 mm) across the full gage length and keep total indicated runout under 0.001 in (0.025 mm). Check taper by micrometer at three or more locations, spaced 0.5 in (13 mm) apart, and record to 0.0001 in (0.002 mm). Blend transitions to shoulders smoothly to prevent localized yielding, following the selected standard’s geometry.
A reliable workflow is rough turn, leave 0.010 to 0.020 in (0.25 to 0.50 mm) stock, semi-finish, then a single finish pass removing 0.002 to 0.005 in (0.05 to 0.13 mm). For common steels with carbide tooling, start near 150 to 350 SFM (45 to 105 m/min) and 0.002 to 0.004 in/rev (0.05 to 0.10 mm/rev), then adjust based on hardness and tool wear. After machining, lightly break edges 0.010 in (0.25 mm) and, if required, perform a final longitudinal polish with 600 to 1200 grit media.
If you would like application-specific guidance, you can explore model options and typical capabilities on the All Round Sample Preparation Products page.
How Can I Maintain Concentricity, Surface Finish, and Tolerance When Preparing Round Tensile Specimens?
Begin with straight stock, face and center drill both ends, then machine between centers with a drive plate and lathe dog or a precision collet with a live center for slender blanks. Verify total indicated runout at the gage section, targeting 0.001 in TIR (0.025 mm) or better before the finish pass. Use steady rest support when the unsupported length exceeds 6 in (150 mm) to limit chatter and tool deflection.
Use a two-stage approach. Rough turn to leave 0.010 in (0.25 mm) of material, then finish to the final diameter within ±0.0005 in (±0.013 mm). For common metallic specimens to ASTM E8 and ISO 6892-1, typical geometries include 0.500 in (12.5 mm) gage diameter with 2.00 in (50 mm) gage length, or 0.250 in (6.0 mm) with 1.00 in (25 mm). Aim for ≤63 µin Ra (1.6 µm) on the gage, and if notch sensitivity is a concern, target ≤32 µin Ra (0.8 µm). Avoid tool marks transitioning into the gage and blend radii smoothly at shoulders.
Select a stable tool nose radius near 0.015 in (0.4 mm), apply flood coolant on steels and superalloys, and consider a spring pass to remove elastic recovery. For the final finish, use longitudinal polishing only, progressing through 400 to 600 grit, while keeping polishing bands inside the gage length. Confirm diameter at three locations along the gage, record TIR, and preserve witness center holes for post-test fractography when required.
If you would like to compare chucking options, sizes, and automation for round specimen machining, you can review details on the All Round Sample Preparation Products page.
How Should Labs Choose Between Flat-Specimen and Round-Specimen CNC Equipment For ASTM E8 and ISO 6892 Programs?
Start with your incoming material and governing standard. Sheet, strip, and plate typically drive a milling-type system for dog-bone coupons, while bar, rod, and machined components favor a lathe-style system for round bars. If the specification calls for a proportional round sample or threaded ends, a round-specimen machine is the efficient path. When standards permit either form, choose the geometry that best represents the product form and simplifies measurement for your team.
Match machine capability to tolerances and finish targets. A good benchmark for flat coupons is ±0.002 in (±0.05 mm) on width and thickness with smooth fillet transitions. For round bars, plan for diameter control within ±0.0015 in (±0.04 mm) and concentricity near 0.001 in (0.025 mm). Many labs target Ra 32–63 µin (0.8–1.6 µm) in the gauge, achieved with sharp tooling, proper coolant, and light finishing passes. Common dimensions include 2.00 in (50 mm) gauge length for flat sub-size coupons and 0.505 in (12.83 mm) diameter round specimens where allowed by ASTM E8/E8M.
Consider throughput and features. If you produce many round bars, a rigid lathe with tailstock support, threading cycles, and optional bar feed improves cadence. For varied flat work, look for travels around 12 in × 6 in × 6 in (305 mm × 152 mm × 152 mm), fast workholding, and an automatic tool changer. Labs that routinely test both sheets and bars often deploy one of each style to keep schedules predictable and results consistent.
If you would like to review configuration options for both flat and round systems, feel free to connect with our team on the Contact Us page.
How Should Labs Choose Between Flat-Specimen CNC Mills and Round-Specimen CNC Lathes?
Start with incoming stock and the governing standard. Sheet, strip, and plate are most efficiently machined as flat dog-bones on a milling platform, while rods and bars are best prepared as round specimens on a lathe. For metals, ASTM E8/E8M and ISO 6892 outline proportional geometries, so select the machine that matches the required coupon form. If thickness is limited, flat coupons are often the practical path. When both are allowed, round bars can simplify stress calculations and reduction-of-area measurements.
Build your quality targets into the program and inspection plan. Common lab goals are diameter within ±0.001 in (±0.025 mm) for round gauges, width and thickness within ±0.0015 in (±0.04 mm) for flat gauges, and fillet radii within ±0.002 in (±0.05 mm). Aim for 32 to 63 µin Ra (0.8 to 1.6 µm) on the gauge section. Leave finish stock of 0.030 to 0.060 in (0.8 to 1.5 mm) for final passes, use sharp tooling, and apply coolant to avoid altering the surface layer. Deburr lightly, then polish only as needed to remove tool marks without changing dimensions.
Match the machine to throughput and workflow. A benchtop mill can produce a flat coupon in a few minutes, while a lathe with a tailstock and proper centers keeps TIR under 0.002 in (0.05 mm) across the gauge. For mixed workloads, many labs pair a flat system from the TensileMill CNC line with a round-prep TensileTurn unit to cover all materials efficiently.
If you would like to discuss selection criteria for your materials and standards, feel free to connect with our team on the Request a Quote page.
How Should I Set Up CNC Tooling, Fixturing, And Tolerances For Flat Versus Round Tensile Specimen Preparation?
For flat coupons, use a rigid vise or dedicated plate fixture that supports the gauge and fillet regions, and verify parallelism of the work surface within 0.001 in (0.025 mm). Keep clamp pressure low near the gauge to avoid distortion. For round bars, hold in a precision collet or soft-jaw chuck with a live tailstock center, and keep total indicated runout at or below 0.001 in (0.025 mm). Add 60° center holes with an entrance diameter near 0.10 in (2.5 mm) to maintain concentric support, and limit unsupported overhang to 3–4 in (75–100 mm).
Tooling differs by geometry. Flat specimens respond well to carbide end mills, 3/8–1/2 in (10–12 mm) diameter, with a light finishing pass of about 0.010 in (0.25 mm) per side using climb milling. Deburr edges minimally, about 0.005 in (0.13 mm). For round specimens, use finishing inserts with 0.016–0.032 in (0.4–0.8 mm) nose radius, depth of cut 0.004–0.008 in (0.10–0.20 mm), and feed 0.003–0.006 in/rev (0.08–0.15 mm/rev). Face ends square and add a 0.010 in × 45° (0.25 mm × 45°) chamfer. In both cases, apply flood coolant at 5–10 percent concentration to control temperature.
As practical targets, hold width or diameter within ±0.002 in (±0.05 mm), straightness within 0.002 in per 6 in (0.05 mm per 150 mm), and surface finish in the gauge section between 32–63 μin Ra (0.8–1.6 μm). Verify geometry against the selected standard, such as ASTM E8/E8M or ISO 6892 for metals and ASTM D638 or ISO 527 for plastics. Measure round diameters at three axial locations, and for flat coupons measure width and thickness in the necked region. Avoid cold work by keeping the part under 120°F (50°C), then, if needed, apply a light longitudinal polish to remove tool marks.
If you would like to review equipment options and sizing for your lab, you can connect with our team on the Contact Us page.
What Tolerance, Concentricity, and Surface Finish Targets Should We Use for Flat vs Round Tensile Specimens?
For flat coupons prepared to ASTM E8/E8M or ISO 6892, labs commonly hold width and thickness within ±0.002 in (±0.05 mm) and keep fillet radii within ±0.005 in (±0.13 mm). Cut edges should be smooth, typically 63–125 µin Ra (1.6–3.2 µm), with machined faces, if required, at about 32–63 µin Ra (0.8–1.6 µm). Break sharp edges lightly, about 0.005–0.015 in (0.13–0.38 mm), and ensure the gauge section is uniform through thickness. Verify at multiple points across the reduced section, not just at mid-length.
For round bars, diameter control drives data quality. A practical target is ±0.001 to ±0.002 in (±0.025 to ±0.05 mm) on the gauge, total indicated runout at or below 0.001 in (0.025 mm), and straightness within about 0.002 in over 6 in (0.05 mm over 150 mm). Surface finish on the gauge is typically 32–63 µin Ra (0.8–1.6 µm). If threaded grips are specified by the standard, cut threads after finishing the gauge to avoid distortion, and use 60° center holes to support the work during turning.
Process tips help you achieve these targets. On flat systems, use full-face fixturing, finish with a light climb-mill pass around 0.005 in (0.13 mm) radial, apply coolant, then deburr without rounding the gauge. On round systems, use a collet or soft jaws with a live center, finish in multiple light passes of 0.002–0.004 in (0.05–0.10 mm), and polish longitudinally. Preloaded templates in TensileMill CNC and TensileTurn CNC equipment help enforce geometry and compliance checks.
If you would like to discuss your testing requirements, feel free to connect with our team on the Contact page.
How Do I Choose Between Flat and Round Tensile Specimen CNC Systems for ASTM E8 and ISO 6892 Work?
Start with material form and the governing standard. Sheet, strip, and plate, typically 0.04–0.50 in (1.0–12.7 mm) thick, are prepared on a flat-specimen CNC mill per ASTM E8/E8M or ISO 527. Bars and rods, often 0.25–1.00 in (6.4–25.4 mm) diameter, are turned on a round-specimen CNC lathe for ASTM E8 or ISO 6892 work. When a material could be tested either way, follow the product form specified by the standard to keep results comparable.
For flat coupons, hold width and thickness uniformly, probe stock before cutting to minimize taper to under 0.0008 in (0.02 mm), and program the correct shoulder radii from the selected method. Use sharp carbide end mills, climb milling, and flood coolant to avoid cold work. Many labs target edge quality that deburrs to a smooth finish near 32–63 µin Ra (0.8–1.6 µm).
For round bars, center-drill each end, support with a live center, and limit total indicated runout to 0.001 in (0.025 mm) across the gauge length. A 0.015 in (0.40 mm) insert nose radius and light finishing passes help achieve a uniform surface and stable diameter. If your workload regularly includes both sheets and bars, the most efficient path is one dedicated machine of each type. If you must pick one first, select the platform that covers at least 80 percent of your daily specimens.
If you would like to compare round-specimen options, you can explore details on the All Round Sample Preparation Products product page.
How Does the Upgraded TensileTurn Classic Support ASTM E8 and ISO 6892-1 Round Specimen Tolerances?
Operators select an ASTM E8 or ISO 6892-1 template on the 15 in (381 mm) touchscreen, then enter target gauge diameter, gauge length, and fillet radii. The software builds toolpaths around those limits, and the operator sets tool offsets with a quick test cut and mic checks. A tailstock center and 3-jaw chuck hold the blank on axis, which keeps runout low across the gauge section.
A 3 hp (2.2 kW) spindle with up to 4000 rpm maintains cutting speed on steels and nickel alloys. Positioning capability of X ±0.002 in and Z ±0.001 in, with repeatability of ±0.0001 in, supports tight diameter and length tolerances. Travel covers 7.1 in (180 mm) on X and 18.3 in (465 mm) on Z, and rapid traverse reaches 315 in/min (8000 mm/min). The 1.02 in (26 mm) spindle bore, MT4 taper, 4-position tool changer, and a 6.6 gal (25 L) coolant tank allow stable roughing and light finishing passes, for example 0.005–0.010 in (0.13–0.25 mm) depth at 0.002–0.004 in/rev (0.05–0.10 mm/rev).
For throughput, the triple clamping fixture can process three parts at once. The machine handles specimens up to 16 in × 2 in (406 mm × 51 mm) and fits in a 62.5 in × 27.75 in × 59.65 in (1590 mm × 705 mm × 1515 mm) footprint.
If you would like to review configuration options and detailed specifications, you can explore the TensileTurn CNC – Classic Upgrade product page.
How Does the TensileTurn CNC Classic Upgrade Accelerate Round Specimen Prep While Meeting ASTM E8 and ISO 6892?
The Classic Upgrade is a purpose-built CNC lathe for round tensile specimens with standards templates built into the controller. An operator selects ASTM E8 or ISO 6892 geometry, loads blanks, and starts the cycle. Button-head, threaded-end, sub-size, fatigue, and impact geometries are supported. For higher throughput, stacked clamping can machine multiple blanks in one run. Materials up to 55 HRC are handled without special machining centers or outsourcing.
A practical setup starts with a sharp carbide insert with a 0.016 in (0.4 mm) nose radius, tailstock engaged, and steady coolant. For steels up to 55 HRC, rough at 0.010–0.015 in/rev (0.25–0.38 mm/rev) and 300–500 SFM (90–150 m/min). Finish at 0.003–0.006 in/rev (0.08–0.15 mm/rev) with a 0.005–0.010 in (0.13–0.25 mm) depth of cut to maintain a smooth, uniform gauge section.
Before releasing a specimen, break shoulder edges with a 0.02 in (0.5 mm) blend. Check runout below 0.001 in (0.025 mm) and verify gauge parallelism with micrometer checks every 0.5 in (13 mm). ASTM E8 and ISO 6892 call for an axially symmetric gauge free of stress concentrators, so look for tool marks and alignment issues prior to testing.
If you would like to review throughput features and standard templates, you can explore details on the TensileTurn CNC Classic Upgrade product page.
How Do Labs Plan An In-House Tensile Specimen Preparation Setup That Meets ASTM And ISO Requirements?
Start with your standards and geometry library. For metals, ASTM E8 subsize and full-size choices often use 2.0 in (50 mm) or 1.0 in (25 mm) gage lengths; plastics commonly follow ISO 527 geometries. A software-driven workflow that lets operators pick a template, then locks critical dimensions and shoulder radii, reduces programming mistakes and shortens onboarding for new staff.
Match equipment to stock. Use a flat-specimen milling system for dog-bone blanks from plate or sheet, and a round-specimen CNC lathe for bars and rods. For consistent finish, leave about 0.020 in (0.50 mm) per side for a final pass near 0.008 in (0.20 mm). Target a surface roughness near 63 µin (1.6 µm) or better; if tool marks remain, a longitudinal polisher helps clean the gauge section without rounding edges.
Plan the workflow details. Keep dedicated fixtures that center the blank on the machine axis and prevent tilt. Stage duplicate cutters and inserts, and track tool life by part count instead of time. Use workholding that clamps outside the shoulder region so the gage section is untouched. Maintain a small kit of consumables, including end mills, lathe inserts, jaw pads, and polishing media, to avoid stoppages.
If you would like to review sample-prep options for your lab, you can connect with our team on the Contact Us page.
How Should Labs Plan Service and Calibration for Tensile Specimen Preparation and UTM Systems?
Plan annual force verification for UTMs to ASTM E4 or ISO 7500-1, with a maximum interval of 18 months. Reverify after relocation, repairs, or any out-of-tolerance result. In daily use, warm electronics 20 to 30 minutes, check zero, and confirm load-train seating and grip face condition. Log rate control and encoder checks. For alignment, follow ASTM E1012 when required by method or customer, or after grip or fixture changes.
For tensile sample preparation machines, set a practical PM rhythm. Monthly, check spindle runout and toolholders, aiming for ≤ 0.001 in (≤ 0.025 mm). Verify vise or chuck runout and, on lathes, tailstock center height. Cut a verification coupon and confirm critical dimensions to ± 0.001 in (± 0.025 mm) against a calibrated reference.
Budget for consumables and spares that wear, such as end mills, inserts, collets, jaw inserts, and belts. Schedule remote software updates on a set cadence, for example quarterly. Maintain one log that ties calibrations, PM tasks, certificates, and operator training to specific serial numbers. This documentation keeps audits predictable under ISO/IEC 17025, ASTM E4, and ISO 7500-1.
If you would like to review accredited methods and scheduling options, you can read the Certification for Testing Equipment page to explore details on the information page.
How Does a Single-Vendor Tensile Testing Workflow Improve Compliance and Throughput?
A single-vendor workflow ties specimen preparation, polishing, and tensile testing into one chain. Operators work from standard libraries aligned to ASTM and ISO geometries, which cuts programming steps and reduces mismatches between machined dimensions and test fixtures. Lead time drops because blanks move directly from the mill or lathe to the tester, while one support group handles installation, calibration, and training.
Typical chain: flat milling or round turning to the specified gauge and fillet radii, optional longitudinal polish, then testing on a UTM with matched grips and an extensometer. For metals per ASTM E8, a common gauge length is 2 in (50 mm). For plastics per ASTM D638 or ISO 527, Type I and 1A specimens use 2.0 in (50 mm) gauge length. Size the frame to at least twice the predicted failure load, for example 22 kip (100 kN) for many steels.
On the floor, watch details that affect repeatability. Keep gauge length temperature under 150 F (65 C) during machining to avoid local property changes. Inspect cutters every 25 to 50 parts and adjust feed to prevent chatter that raises surface stress. Use wedge or pneumatic grips with serrations matched to hardness, verify alignment per ASTM E1012, and keep spare jaws and sharp inserts on hand to avoid mid-run delays.
If you would like to discuss your workflow, you can connect with our team on the Contact Us page.
What Room Conditions Should Be Maintained During CNC Tensile Specimen Preparation?
Hold the prep room near 68 to 74 F (20 to 23 C) with 40 to 55% relative humidity. For moisture-sensitive plastics, condition material per ASTM D618 at 73.4 ± 3.6 F (23 ± 2 C) and 50 ± 5% RH before machining and testing. Keep fixtures, machine table, and blanks at the same temperature; a 10 F (5.6 C) swing can move aluminum by about 0.0004 in (0.011 mm) across a 6 in (152 mm) gauge length.
Control moisture and contaminants at the machine. Use an enclosed CNC with HEPA extraction to limit dust and oil mist. For metals, remove water-based coolant promptly and dry with clean air; for polymers and composites, avoid water exposure, wipe with isopropyl alcohol, and store in sealed bags with desiccant. Limit air exposure on corrosion-prone alloys, and clean oxide with a light polish that does not change thickness.
Process behavior that improves repeatability: allow raw stock to thermally soak in the lab for at least 30 minutes, machine and measure in the same room, target final dimensional checks at 68 F (20 C), and handle the gauge section with gloves to prevent residue. If a polisher is used, finish and measure within the same environmental window.
For additional guidance, you can contact us through the Contact Us page.
What ROI Thresholds Indicate It Is Time To Bring Tensile Testing In-House?
Start by comparing the calculator’s 12-month outsourcing total to a realistic equipment package. If yearly spend for sample preparation and tensile tests, including shipping, approaches the quoted price of a UTM with grips plus a flat or round specimen machine, payback often falls within 12 to 18 months. Using the default values, 8 flat specimens per week at $240 each with weekly shipping at $50 equals roughly $102,000 per year, which can justify an internal lab for many operations.
Check schedule risk and growth next. A 14-day turnaround holds WIP and pushes lot release. If results routinely gate production or PPAP timing, shorter internal cycles can outweigh a lower annual spend. Apply your expected volume increase, for example 10 percent per year, and review where the in-house curve overtakes outsourcing.
Right-size the equipment to your blanks since dimensions affect price and throughput. Flat blanks under 0.5 in (12.5 mm) thickness and round stock under 4.0 in (100 mm) diameter and 8.0 in (200 mm) length generally fit compact sample-prep systems. Larger inputs may require higher-capacity machines and a different ROI. For ASTM E8 metals or ISO 527 plastics, include proper grips and extensometry in the capital model.
If you would like to review frame capacities, grips, and software options, you can explore details on the All Tensile Testing Equipment page.
How Should Labs Plan Tensile Tests For Recycled And Upcycled Materials?
Recycled feedstock varies by source, melt history, and contamination, so test planning starts with defining the property set needed for use. Typical targets are yield and ultimate strength, modulus, and elongation. Batch variability makes lot tracking and consistent geometry essential, otherwise small shifts in section or surface act as unintended stress raisers.
For plastics, machine dog-bone coupons to ASTM D638 Type I, 0.125 in (3.2 mm) thick with 2.0 in (50 mm) gauge length, and finish edges to about 32 µin Ra (0.8 µm). For metals, ASTM E8 subsize round at 0.25 in (6.0 mm) diameter with 1.0 in (25 mm) gauge length works well. Hold flow direction or rolling direction consistent across lots.
Set conditioning at 73.4 F (23 C) and 50 percent RH. Use 0.2 in/min (5 mm/min) crosshead speed for many plastics per D638 materials, and about 0.05 to 0.5 in/min (1 to 13 mm/min) for metals per E8 targets. Apply a small preload, 5 to 20 lbf (22 to 89 N). Use a 1.0 to 2.0 in (25 to 50 mm) extensometer and test at least five specimens per lot.
If you would like to discuss your testing requirements, you can reach our team on the Contact Us page.
What Test Volume Justifies Bringing Tensile Specimen Preparation In House?
Use a simple crossover check. Tally your current external spend per month, including test fee, per-specimen prep, shipping, and any rush charges. Compare that to in-house variable cost, which includes operator time per specimen, consumables, and machine financing or depreciation. For many operations the crossover appears when monthly volume reaches roughly 25 to 50 specimens, especially when geometries repeat across jobs and schedules are tight.
Technical signals help the decision. If you routinely send flats with a 2 in (50 mm) gauge length at about 0.125 in (3.2 mm) thickness or rounds at about 0.25 in (6.4 mm) diameter, batch machining yields consistent parts with short setups. Stacking 2 to 4 blanks reduces part-to-part handling, and typical cycle times of 3 to 6 minutes per specimen are achievable on aluminum and common steels. A gauge finish near 32 µin Ra (0.8 µm) supports repeatable strain measurement and reduces retest risk.
Start with a pilot lot. Dial feeds and speeds until edges break cleanly, then validate dimensions against your chosen standard. Check gauge width and thickness at three locations with a 0.0005 in (0.013 mm) resolution instrument and record heat numbers to keep traceability intact.
If you would like to compare system options, you can review details on the Flat Tensile Sample Preparation Machines equipment page.
How Can In-House Specimen Preparation Cut Tensile Testing Lab Fees?
Third-party labs often add charges for specimen machining, surface finishing, rework, rush handling, and shipping. Moving specimen preparation in house with a flat or round CNC and a simple polisher reduces those add-ons. Operators can stack two or three blanks 0.125 in (3.2 mm) thick with a spacer and cut multiple coupons in one cycle. Grouping jobs by alloy and thickness reduces tool changes and repeated metrology setups, which lowers per-coupon labor time.
Run a consistent workflow. Saw stock slightly oversize, then leave 0.020 in (0.50 mm) per side for finishing. Use a final pass of about 0.005 in (0.13 mm) to stabilize edges and limit cold work. Deburr lightly with 0.010 in (0.25 mm) edge breaks. If the lab requests a smooth gauge section, target around 32 µin Ra (0.8 µm). Match geometry to ASTM E8 for metals with a 2.00 in (50 mm) gauge length, or use the applicable ISO 527 type for plastics to avoid rejection and retests.
Before shipment, verify width and thickness at three locations across the gauge length, check parallelism on a surface plate, and record heat lot and program ID. Keep a spare end mill ready and replace at the first sign of burnishing. Ship in larger batches to one lab to reduce per-sample pricing and freight.
If you are planning an in-house lab, you can explore details on the All Flat products equipment page.