In this application, a deep-drilled bore in 17-4PH is finish-honed to approximately Ø47 mm. The nominal radial stock allowance is about 70 µm. At the same time, the component geometry requires a long-reach tool and defined free space behind the bore so that the honing stones can overtravel completely.
The tooling design combines a six-stone coolEXact® honing tool with µ-matik® fine adjustment and an HSK-A100 holder. coolEXact® provides a mechanical expansion limit, while µ-matik® adjusts the finished size in small, repeatable steps. Tool guidance, size correction and wear compensation are therefore integrated into one coordinated system.
| Characteristic | Documented value |
|---|---|
| Material | 17-4PH |
| Pre-machining | deep-hole drilling to Ø46.85 ±0.05 mm |
| Honed size | Ø46.99 ±0.025 mm |
| Nominal radial honing allowance | approx. 70 µm |
| Tool principle | six-stone coolEXact® honing tool |
| Honing-stone length | 80 mm |
| Fine adjustment | µ-matik® 72Z, 3.7 µm per detent step |
| Machine interface | HSK-A100 |
| Tool reach | approx. 700 mm to the holder |
| Free space behind the bore | at least 70 mm |
The coolEXact® honing tool uses a defined expansion stop. This limits the effective tool diameter and allows the tight finished size to be approached in a controlled manner. Six honing stones distribute the contact forces evenly around the circumference and support guidance in the long bore.
The µ-matik® fine adjustment mechanically corrects the expansion stop. The documented 72Z version provides an adjustment resolution of 3.7 µm per detent step. This repeatable adjustment is particularly useful when the long-reach tool should not be removed from the machine for frequent manual correction.
The HSK-A100 holder provides a stiff, repeatable connection to the machine spindle. With a long-reach solution, tool mass, centre of gravity, overturning moment and the spindle's dynamic suitability must be checked by the machine operator before commissioning.
Check pre-machining: The deep-drilled bore is checked for diameter, straightness and remaining stock. The nominal radial allowance of about 70 µm must not be considered in isolation because the pre-machining tolerance changes the actual amount to be removed.
Provide complete stone overtravel: The 80 mm honing stones require at least 70 mm of free space behind the bore. Adequate overtravel is necessary to machine the full functional length evenly and avoid local over-processing at the bore end.
Approach size in a controlled manner: coolEXact® limits expansion. µ-matik® corrects the stop step by step until the target diameter is reached. Diameter and geometry are checked after every correction before another adjustment is made.
Control the long overhang: Tool guidance, spindle interface and the motion sequence must be coordinated so that the long tool does not generate vibration or one-sided loading. The six honing stones support uniform circumferential guidance.
Compensate for wear: In production, µ-matik® can correct the wear-related reduction in effective tool diameter. Every permitted adjustment is verified by size and geometry measurements.
| Check area | Technical significance |
|---|---|
| Spindle and holder | HSK-A100, tool mass, centre of gravity and overturning moment require approval |
| Collision envelope | long tool reach and complete stroke path must remain clear |
| Overtravel | at least 70 mm of free space behind the bore is required |
| Pre-machining | check diameter, straightness and stock distribution of the deep-drilled bore |
| Size strategy | apply µ-matik® steps only together with diameter and geometry measurement |
| Honing stones | match the specification to 17-4PH, the required surface and actual stock allowance |
The drawing documents the tooling design, not production results. A commissioning trial, machine-side collision check and a measurement strategy for diameter, roundness and straightness must therefore be defined before productive use.
Why is coolEXact® used for this application? The defined expansion stop supports a controlled approach to the finished diameter. This is useful when a tightly toleranced honed size must be produced from a deep-drilled bore.
What is the role of µ-matik®? µ-matik® adjusts the expansion stop in repeatable steps. Finished size and wear compensation can therefore be corrected without changing the basic tool design.
Why are six honing stones specified? Their even distribution around the circumference improves tool guidance and distributes machining forces. This is particularly important with a long tool overhang.
Why is free space required behind the bore? The honing stones must travel beyond the bore end. Without this overtravel, form errors or uneven machining may occur at the end of the bore.
Are the documented dimensions already production results? No. The available document describes the mechanical tooling and process design. Measurements, cycle time and tool life must be established and approved during commissioning.
How are the process parameters established? The setup depends on the machine, coolant, honing-stone specification, actual stock allowance and required surface. The specific values are therefore determined on the machine during commissioning.
The six-stone coolEXact® honing tool with µ-matik® fine adjustment combines a defined expansion limit with repeatable size correction. For the deep Ø47 mm bore in 17-4PH, the design accounts for a nominal radial allowance of about 70 µm, 80 mm honing stones, HSK-A100 and the necessary overtravel behind the bore. This provides the technical basis for a controlled commissioning process; production values will be defined only after machine approval and measurement validation.
Related DIAHON sections: coolEXact® and µ-matik®.