About Kezuriba

What this site is

KEZURIBA is a free technical reference and calculation toolbox for metal cutting and machining engineers, CNC operators, process planners, and mechanical designers. It brings together data that is usually scattered across standard handbooks, tool maker catalogs, and machine manuals—with every figure linked to its primary source so you can verify it on the spot.

• Machining calculators (19 tools): cutting speed and spindle RPM (turning, milling, drilling, tapping, reaming, boring, ball end mill), cutting power and specific cutting force, chatter-free spindle speed, thread dimensions, taper angles, bolt tightening torque, press-fit interference, thermal expansion, theoretical surface roughness, PCD hole coordinates, material weight, hardness conversion, and tool holder balance.
• Materials database (150 grades): steels, stainless steels, aluminum alloys, copper alloys, cast irons, titanium alloys, nickel superalloys, aerospace grades, and engineering plastics—covering chemical composition, mechanical properties, physical properties, international equivalents (JIS / ISO / ASTM / EN / DIN / GB), specific cutting force kc1, heat-treatment effects, and chip control.
• Threads & fasteners (64 pages): metric coarse and fine threads (M1 to M68), Unified threads (UNC / UNF), pipe threads (G / R / Rc / NPT), tap drill recommendations compared across OSG, Nachi-Fujikoshi, and Yamawa, counterbore dimensions, and dowel/taper pins.
• Fits & tolerances (102 pages): ISO 286 / JIS B 0401 hole and shaft tolerance zones (51 classes), interactive fit calculator, IT grades, and general geometrical tolerances.
• G/M codes · Tooling · Measuring instruments · Troubleshooting · Machine maintenance: 150 G/M code pages, spindle tapers and holders (BT, BBT, HSK, Capto, KM, ER), 39 measuring instruments, 45 machining troubleshooting guides, 50 machine tool maintenance guides, and technical articles.

All calculators run entirely in your browser and support offline use (PWA) for shop floors with poor signal reception. Pages are available in Japanese, English, and Simplified Chinese.

Operator information

Editorial and verification policy

In machining, a wrong tap drill diameter, tolerance value, or cutting parameter leads directly to scrapped parts or broken tools. We follow six strict rules when compiling every page:

1. Primary sources only: Every numerical value is taken from public technical documents issued by standards bodies, public research institutes, or tool, material, and machine tool manufacturers. We do not copy unverified numbers from secondary blogs or Q&A sites.
2. Numbered inline citations: Numbers in tables and text carry numbered reference links ([1], [2], …) pointing to the exact source URL listed at the bottom of the page.
3. Three-tier confidence badges: Material composition, mechanical properties, equivalents, and fastener dimensions are labeled as “Agrees in 2+ sources”, “One source / reference”, or “Not confirmed”. Values that could not be verified in primary sources are left blank (—) rather than guessed.
4. Side-by-side comparison when makers differ: When tap drill recommendations, ISO material groups (e.g. P vs. M, or M vs. S), or specific cutting forces kc1 differ between tool makers, we list each maker’s published figure side by side instead of averaging them.
5. Separating standards from shop-floor rules of thumb: Normative values from ISO / JIS / ASTM standards are clearly distinguished from empirical shop-floor guidelines and maker catalog recommendations.
6. Prompt corrections: When a standard is revised, a maker updates its catalog, or a reader reports an error via the contact form, we re-verify the primary source and update the page.

Main primary sources cited

• Standards & public institutions: JISC (Japanese Industrial Standards Committee), JSA (Japanese Standards Association), NIST, Ministry of Economy, Trade and Industry (METI), Ministry of Health, Labour and Welfare (MHLW), JAVADA, JMTBA (Japan Machine Tool Builders’ Association)
• Cutting tool makers: Sandvik Coromant, ISCAR, Mitsubishi Materials, Tungaloy, Sumitomo Electric Hardmetal, Kyocera, OSG, Nachi-Fujikoshi, Yamawa
• Measuring instrument, gear & component makers: Mitutoyo, Keyence, Noritake, KHK (Kohara Gear Industry), Kyouiku Gear, Gleason, Liebherr, THK, NSK, NTN, BIG DAISHOWA, MST Corporation, NT Tool, Nikken Kosakusho, NBK
• Material makers & associations: Nippon Steel, JFE Steel, Kobe Steel, Daido Steel, Proterial (formerly Hitachi Metals), Aichi Steel, Sanyo Special Steel, UACJ, Japan Aluminium Association, Japan Stainless Steel Association, Copper Development Association (CDA), Deutsche Edelstahlwerke (DEW), Mitsubishi Chemical Advanced Materials (MCAM)

All company names, product names, and brand designations mentioned on this site are trademarks or registered trademarks of their respective owners. This site is an independent technical reference and is not affiliated with or endorsed by any specific manufacturer.

Advertising and monetization

To cover server hosting, domain, and technical reference costs while keeping all tools free, this site uses:

• Display advertising (Google AdSense): Ads may be displayed in designated slots.
• Affiliate links (Amazon Associates Japan, Rakuten Affiliate, etc.): On Japanese pages, boxes marked “PR” may link to related measuring tools or technical books.
• Printable PDF reference sheets: Paid A4 shop-floor reference sheets may be offered on BOOTH (pixiv). All web pages and calculators on this site remain completely free.

Advertising and affiliate relationships never influence which values, formulas, or manufacturer sources are cited on this site. See our Privacy Policy & Disclaimer for details on cookies and data handling.

Contact and corrections

If you spot a numerical or typographical error, or if you represent a manufacturer or standards organization requesting a correction, please let us know via the Contact page.