# HSK-A100 interface

HSK-A100 hollow-taper geometry, face contact, form differences and assembly-specific operating limits.

Reviewed: 2026-11-02

Tags: tooling, toolholding, spindle-interfaces

## Identity and load path

HAIMER's 2020 catalog lists HSK-A100 at **100 mm flange diameter**, **75.013 mm tabulated taper diameter (D3)** and **50 mm shank length**. Form A locates at the taper and flange face, with internal clamping, drive features and a peripheral groove for automatic handling. Verify those interfaces and the coolant connection against the spindle drawing before qualifying a replacement. [HAIMER catalog, p. 74](https://www.haimer.com/shop/catalog/downloads/files/Tool-holders/Tool-holders_US.pdf#page=74), [ISO 12164-1:2023 scope](https://www.iso.org/standard/77916.html), [HSK overview, volume 3, p. 12](https://catalog.bigdaishowa.com/view/561181695/12/).

ISO 12164-1:2023, edition 2, covers male hollow-taper shanks with flange contact. Its public abstract distinguishes the peripheral automatic-change groove of type A from ungrooved type C. Type A also allows manual change through radial access holes. Clamping fingers engage inside the shank and draw the holder into the spindle. BIG DAISHOWA describes elastic expansion of the thin taper as part of dual contact. [BIG DAISHOWA dual-contact explanation](https://www.bigdaishowa.com/en/blog/faq-big-plus-dual-contact), [BIG DAISHOWA internal-clamping explanation, March 19, 2024](https://www.bigdaishowa.eu/en/news/detail/?news_id=16635).

## Size 100 and catalog geometry

HAIMER's *Tool Holders*, first edition 2020, lists the following HSK-A interface dimensions. Symbols refer to that catalog's drawing; these are selected catalog values, not a complete dimensioned definition or tolerance specification. [HAIMER catalog, p. 74](https://www.haimer.com/shop/catalog/downloads/files/Tool-holders/Tool-holders_US.pdf#page=74)

| Interface | Flange diameter D1 | Taper diameter D3 as tabulated | Shank length L1 |
| --- | --- | --- | --- |
| HSK-A63 | 63 mm | 48.010 mm | 32 mm |
| HSK-A80 | 80 mm | 60.012 mm | 40 mm |
| HSK-A100 | 100 mm | 75.013 mm | 50 mm |

The same drawing labels the taper 1:9.98. HAIMER also states that HSK needs no pull stud. The size number follows the flange diameter in this table; it is neither a 100 mm cutter bore nor a 100 mm taper diameter. [HAIMER interface drawing and notes, p. 74](https://www.haimer.com/shop/catalog/downloads/files/Tool-holders/Tool-holders_US.pdf#page=74)

**Worked comparison:** A100/A80 flange diameter = 100/80 = 1.25. This linear ratio is not a stiffness or allowable-torque ratio. Their different taper diameters preclude direct substitution.

## Form A versus other HSK forms

REGO-FIX's catalog distinguishes these forms by their handling, drive and coolant features. These are form descriptions, not a universal cross-mating table. [REGO-FIX main catalog, printed p. 305](https://regousa.com/wp-content/uploads/2022/04/REGO-FIX-Main-Catalogue-ENGLISH.pdf#page=309)

| Form | Tool change | Distinguishing catalog features |
| --- | --- | --- |
| A | Automatic | Central coolant tube; drive keys at taper end |
| B | Automatic | Enlarged flange; flange coolant supply and drive keys |
| C | Manual | Drive keys at taper end |
| E | Automatic | Central coolant tube; no drive keys, for rotational symmetry |
| F | Automatic | Enlarged flange; no drive keys, for rotational symmetry |

**Interpretation:** the letter carries information that the size alone omits. Shared HSK naming or flange size does not establish interchangeable taper geometry, torque transmission or changer handling. The current ISO 12164-1:2023 title lists A, AB, C, CB and EB; the older manufacturer's A–F vocabulary should not be mistaken for that edition's complete type list. [ISO edition and type list](https://www.iso.org/standard/77916.html)

## Coolant and automatic tool changing

TAC Rockford's HSK-A100 coolant tube 699.100.190 has length L = 44 mm, thread G = M24×1.5, outside diameter d = 16 mm and bore d1 = 12 mm. Its separate plug 699.115.190 closes the coolant passage for applications such as gauges or tools without coolant. The sheet is marked Rev. 12-1101; this reference retains that identifier without interpreting it as a calendar date. [TAC coolant tube and plug data, p. 1](https://tacrockford.com/pdf/699.100/699100-hsk-coolant-tubes.pdf)

**Interpretation:** the coolant tube is a distinct component, not a pull stud or a cutter-size designation. A suitable central passage does not establish installed pump pressure, sealing compatibility or through-tool delivery. Likewise, type A's changer groove establishes a handling feature, not a machine's allowable tool mass, overturning moment, envelope or magazine clearance.

## Torque, speed and assembly limits

**Worked load example, explanatory synthesis:** assume a spindle delivers 20 kW mechanically at 6,000 rpm. Angular speed is 2π × 6,000/60 = 628.3 rad/s, so torque T = P/ω = 20,000/628.3 = 31.8 N·m. At 3,000 rpm, the same assumed power would require 63.7 N·m. This describes power and torque at an operating point; it is not an HSK-A100 rating, a drawbar-force value or a coolant-tube installation torque.

Neither size 100 nor the existence of drive keys gives a universal maximum speed or cutting torque. Those limits depend on the actual spindle, clamping system, holder, cutter and balance condition. A spindle interface also does not define the holder's tool-side mechanism: collet, shrink-fit, hydraulic and milling-arbor arrangements introduce their own dimensions and limits.

## Coverage and source limits

This article describes interface identity and selected manufacturer geometry. It does not reproduce the standard's full tolerances, inspection requirements or receiver definition, and it does not establish conformance of an installed assembly. Contact damage, clamping force, coolant configuration and machine-specific changer limits remain application-specific unknowns.

HAIMER explicitly identifies its catalog as first edition 2020. The cited REGO-FIX main catalog carries code 0362.00251 / ENG.1 without an established issue date; BIG DAISHOWA's internal-clamping article is dated March 19, 2024, while its cited FAQ and catalog overview supply no issue date in the cited text. URL directory dates and crawl dates are not source editions. The reviewed date describes this article's research review.

## Related reference

[Cutting tools and tooling references](../index.md)