A machine’s accuracy figures and safety claims only mean something when you know which standard they were measured or designed to. This is the reference for comparing two machines honestly and for knowing what you put at risk when you change one.
Two brochures can both say “positioning accuracy” and mean different things: different standards, statistical definitions, temperatures, travel lengths and compensation states. Before you compare, find out the standard (for example ISO 230-2 or ASME B5.54), the measured axis length, whether the result is bidirectional, and whether compensation was active. A test report from the actual machine beats any catalog number.
Guards, interlocks, safe-speed functions and the electrical design are part of how a machine conforms to the safety standards of the market it was built for. Removing a guard or bypassing an interlock does not just raise risk; it can take a machine out of conformity and create legal exposure for the owner and for anyone who sells it on.
Issued by ISO (TC 39/SC 2)
The core family of machine tool test methods. Part 1 covers geometric accuracy under no-load or quasi-static conditions (straightness, flatness, squareness, parallelism). Part 2 covers accuracy and repeatability of positioning of numerically controlled axes. Part 3 covers thermal effects, Part 4 circular tests (the ballbar test), and other parts cover diagonal displacement, rotary-axis geometry and more.
Builders use ISO 230 methods for acceptance tests and published specifications; shops use them to verify a machine after installation, collisions or relocation and to set compensation.
An ISO 230-2 laser report and a ISO 230-4 ballbar plot measured on the machine you are selling are the most persuasive condition documents you can offer.
Ask for test results to a named part of ISO 230, the date, the instrument and whether compensation was active. Re-test after rigging and leveling.
Status (reviewed October 7, 2026): ISO 230-2:2014 is the current positioning-accuracy edition and is the measurement basis referenced by U.S. export-control thresholds for machine tools.
Source: ISO Online Browsing Platform ↗
Issued by ISO (TC 39/SC 2)
Machine-type-specific tests for machining centres: geometric tests for different spindle and table configurations, accuracy of feeds and positioning, tool-change times and the accuracy of a finished test piece.
Why it matters: Gives buyers and builders a shared acceptance-test menu for vertical and horizontal machining centres, including the cut test piece most people actually trust.
Source: ISO Online Browsing Platform ↗
Issued by ISO (TC 39/SC 2)
The turning-centre counterpart to ISO 10791: geometric tests, positioning, thermal and finished-test-piece checks for lathes and turning centres.
Why it matters: Use it to write acceptance criteria for a new lathe or to verify a used one.
Source: ISO Online Browsing Platform ↗
Issued by ASME
U.S. standards that define how to measure and report machine performance (environment, positioning, repeatability, contouring and thermal behavior) so that buyers and builders can specify and accept machines on the same terms.
Why it matters: Common in U.S. purchase specifications and acceptance tests; results are not directly interchangeable with ISO 230 figures unless the methods match.
Source: ASME codes and standards ↗
Issued by ISO (TC 199)
The foundation of machine safety: identify hazards, estimate and evaluate risk, then reduce it in order of preference: inherently safe design, safeguarding, and information for use.
Why it matters: Every machine-specific safety standard and every retrofit risk assessment starts here.
Source: ISO Online Browsing Platform ↗
Issued by ISO (TC 199)
How to design and validate control functions that keep people safe (door interlocks, emergency stops, safe speeds) and rate them by Performance Level, from PL a to PL e.
Why it matters: A control retrofit or a new robot cell must preserve the required Performance Level of every safety function, or the machine is less safe than it was built.
Source: ISO Online Browsing Platform ↗
Issued by NFPA · IEC
Requirements for a machine’s electrical equipment: supply disconnect, protection, control circuits, emergency stop, wiring, grounding and documentation. In the United States the National Electrical Code points industrial machinery to NFPA 79; machines built for Europe and much of the world follow IEC 60204-1. Industrial control panels are commonly listed to UL 508A.
Builders design to the standard of the destination market.
Imported or grey-market machines may need electrical review before they can be installed and inspected in the U.S.
Voltage, phase and disconnect requirements are on the data plate and the electrical drawings; see electrical and power planning. Retrofits should be done to NFPA 79 practice.
Status (reviewed October 7, 2026): The 2024 edition of NFPA 79 is the current edition.
Issued by ISO (TC 39/SC 10)
Machine-type safety standards that set specific requirements for guarding, enclosure strength against ejected parts and tools, interlocks, operating modes and setting-up modes on mills, machining centres and lathes.
Why it matters: The enclosure window and door interlocks on a CNC are engineered to these standards. Replacing a window with the wrong material or defeating a door switch removes protection you cannot see.
Source: ISO Online Browsing Platform ↗
Issued by B11 Standards, Inc. / ANSI
The U.S. consensus standards for machine safety, used alongside OSHA rules. B11.0 sets the general risk-assessment framework, B11.19 covers safeguarding methods and machine-specific parts cover individual machine types.
Why it matters: Used by OSHA, insurers and courts as evidence of recognized good practice.
Source: B11 Standards ↗
Issued by U.S. Occupational Safety and Health Administration
Federal rules employers must follow: machines must be guarded against point-of-operation, rotating-part and flying-chip hazards, and energy sources must be isolated and locked out during service and maintenance.
Machine guarding and lockout/tagout are among the most frequently cited OSHA standards in manufacturing.
Selling a machine with missing guards or bypassed interlocks invites liability; disclose and restore.
Write machine-specific lockout procedures for every new or relocated machine before it runs.
Source: OSHA 1910.212 ↗ OSHA 1910.147 ↗
Issued by European Union
Machines placed on the EU market must meet essential health and safety requirements, carry CE marking and come with an EU declaration of conformity. The Machinery Regulation (EU) 2023/1230 replaces the Directive and applies from January 20, 2027. It defines “substantial modification”: modifying a machine in a way that creates new hazards or increases risk can make the modifier responsible as the manufacturer.
Builders and integrators exporting to Europe need to plan for the new Regulation now.
Used machines sold within or into the EU must still be safe to use; a CE mark from 2008 does not cover changes made since.
A control retrofit, robot integration or guarding change can be a substantial modification. Do the risk assessment before the change.
Issued by ASME B5.50 (CAT, V-flange 7/24 taper) · JIS B 6339 / MAS 403 (BT) · ISO 7388-1 / DIN 69871 (SK) · ISO 12164-1 (HSK) · ISO 26623 (Capto)
These standards define the taper, flange, drive keys and retention method between spindle and toolholder. CAT and BT share the 7/24 taper but differ in flange and pull-stud threads (inch on CAT, metric on BT); HSK is a hollow short taper with face contact; Capto is a polygon coupling. Size numbers (30, 40, 50 for steep tapers; A63, A100 for HSK) indicate capacity.
Holder and pull-stud choice affects rigidity, runout and balance, which shows up in surface finish and tool life.
List the exact spindle interface and pull-stud specification. “40 taper” alone is not enough for a buyer to reuse tooling.
Use only the pull stud specified by the machine builder. A wrong stud, even one that threads in, can reduce clamping force or let a tool release at speed. Budget for new holders when interfaces differ.
Source: ASME codes and standards ↗ ISO Online Browsing Platform ↗
Machine Blue Book does not sell certification, consulting or machines, and is not affiliated with any standards body named here. Standards are copyrighted by their publishers; this reference describes them in our own words and links to the issuing organization. It is educational, not legal or regulatory advice. Facts reviewed October 7, 2026. Found an error or a change? Tell the editor.
