High-Precision Gun Drilling for Automotive & Hydraulic Components

Customer Background

The customer is a precision component manufacturer serving the automotive and fluid power industries — producing injector bodies, hydraulic valve components, and transmission parts that require deep holes with guaranteed dimensional tolerance and surface finish. For these components, the hole’s finish class is a functional specification, not a cosmetic one.

The Challenge

General-purpose deep hole drilling machines often treat hole quality as a byproduct. This customer’s parts do not allow that:

Holes with a stated finish class. Hydraulic and fuel-system components require hole finishing to IT8-IT11 with surface roughness Ra ≤ 3.2µm. The tolerance class is written into the component drawing, so the drilling process must be able to hold it repeatably — not hope to achieve it.

Small-to-medium deep holes. Ø3-35mm holes to 1,000mm cover fuel passages, hydraulic galleries, and transmission oil bores. The aspect ratios are high enough that chip evacuation and tool deflection, not raw power, decide whether the finish class is met.

A mix of materials. Steel, stainless, and alloy components run through the same cell. Each material needs different feed, speed, and coolant behavior to hold the same finish class.

Floor space is limited. The customer operates compact production cells. A large, heavy deep hole drilling machine would not fit the line — they needed drilling capacity in a machine sized for a small footprint.

The Solution

RuidCNC supplied a CNC Gun Drilling Machine (RD1010-10H) — a compact, high-precision gun drilling machine sized for small production cells:

• IT8-IT11 hole finishing precision — guaranteed tolerance class repeatably across the drilling range
• Ra ≤ 3.2µm surface roughness — consistent bore finish for sealing and flow surfaces
• Ø3-35mm drilling to 1,000mm — covers automotive and hydraulic deep hole applications
• Compact design — drilling capacity in a footprint that fits limited-floor-space shops
• 6,000 rpm spindle, 15/18.5 kW — responsive speed and power for a range of materials
• Through-spindle high-pressure coolant — effective chip evacuation to hold finish and straightness at depth
• Programmable CNC drilling cycles — parameter switching for mixed materials without manual reconfiguration

Key Machine Specifications

Parameter	Specification
Drilling range	Ø3 – Ø35 mm
Max drilling depth	1,000 mm
Hole finishing precision	IT8 – IT11
Surface roughness	Ra ≤ 3.2 µm
X / Y / Z axis travel	1,000 / 1,000 / 1,050 mm
Worktable	1200 × 900 mm (28mm T-slots × 6)
Spindle max speed	6,000 rpm
Spindle motor power	15 / 18.5 kW

Results

Metric	Conventional Gun Drilling	CNC RD1010-10H	Improvement
Hole finish class achieved	IT12–IT13	IT8–IT11	1–2 classes better
Surface roughness (Ra)	5.0 µm	2.8 µm	44% better
Scrap from out-of-tolerance holes	3.6%	0.5%	86% reduction
Secondary reaming operations	Required	Eliminated	Eliminated
Batch changeover time	35 minutes	12 minutes	66% reduction
Floor space per machine	Full-size	Compact	~40% smaller footprint

Process Validation

The process was validated through:

• Hole diameter and roundness measurement within the tolerance class
• Surface roughness measurement along full bore length
• Pressure testing of hydraulic and fuel components
• Process capability study (Cpk) across a production batch

Conclusion

The CNC Gun Drilling Machine RD1010-10H delivers drilling capacity in a package that small production cells can use. With IT8-IT11 finishing precision, Ra ≤ 3.2µm surface roughness, and a compact footprint, the customer eliminated secondary reaming operations, cut scrap from out-of-tolerance holes by 86%, and fit deep hole drilling into a floor plan where a full-size machine would not go. For automotive and hydraulic manufacturers whose drawings state a finish class, the RD1010-10H holds it without the secondary operations.

Figures are representative of typical applications.