HSS Long Series Twist Drill Bits

A recessed hole may sit below the surrounding surface. A fixture may prevent the machine from bringing a conventional drill close enough to the entry point. In other cases, the required hole depth simply exceeds what a jobber-length drill can comfortably cover.

This is where the HSS Long Series Twist Drill Bits configuration becomes useful. Compared with a conventional jobber drill, it provides additional overall length and flute length, giving the tool more reach for these machining positions.

That does not mean the longest available drill is automatically the right one. If a shorter tool can complete the operation, there is little reason to add unnecessary length. The better choice is the shortest configuration that provides the required access and working depth.

Key Facts at a Glance

Technical Specifications

Common reference sizes in mm. Final material, geometry, dimensions and availability are confirmed with the quotation.

Reach Where a Standard Drill Cannot

The defining feature of this HSS Long Series Twist Drill Bits is its extended geometry. Rather than changing the basic HSS drilling concept, the long-series format provides additional tool length for applications where reach is the limiting factor.

Extended Overall Length

The increased overall length allows the drill to reach holes positioned farther inside or behind the accessible working area. This is particularly useful when the holder or machine setup cannot approach the workpiece directly.

Longer Fluted Section

A longer flute section provides additional working length for drilling extended holes. The actual usable depth still depends on the drill point, chip space and machining conditions, so flute length should not simply be treated as the maximum hole depth.

Access to Recessed Positions

For recessed surfaces, stepped workpieces or fixtures that restrict the entry position, the additional reach of a DIN 340 drill can make a standard drilling setup more practical.

Familiar HSS Configuration

The reference design uses HSS material, a 118° point, right-hand cutting and a cylindrical shank. This keeps the tool compatible with conventional drilling arrangements while providing the additional length required by the application.

Long Series Does Not Mean “As Long As Possible”

Choosing a long drill should be based on the actual machining envelope.

If the hole is shallow and easily accessible, a stub-length or jobber-length drill may be a better fit. If the entry position is recessed or the hole requires additional reach, the long-series configuration becomes more relevant.

The objective is straightforward: use enough length to reach the hole, but avoid adding unnecessary unsupported length.

For this reason, RONGKE recommends considering the hole depth together with the distance from the tool holder to the workpiece, fixture clearance and the way the drill will be guided into the hole.

RONGKE Long-Series Tool Supply & Customization

RONGKE manufactures standard hole-processing cutting tools and also develops non-standard cutting tools for specific machining requirements. For long-series applications, buyers can provide the required diameter, hole depth, reach, workpiece material and machine information for technical evaluation. If a standard DIN 340 size does not suit the working conditions, RONGKE can assess the dimensional or geometric requirements for a customized tooling solution, with sample trial cutting available where practical verification is required.

FAQ

What is an HSS Long Series Twist Drill?

It is an HSS twist drill manufactured in an extended-length configuration for applications that require more reach than a conventional jobber-length drill. The reference RONGKE series follows DIN 340.

What is the difference between DIN 340 and DIN 338 twist drills?

DIN 340 is associated with long-series drill dimensions, while DIN 338 is commonly used for jobber-length twist drills. The main selection factor is the required reach and drilling depth.

Can HSS Long Series Twist Drill Bits be used for deep holes?

It can handle longer drilling applications within its practical working range, but it should not automatically be regarded as a dedicated deep-hole drill. For a high depth-to-diameter ratio, chip evacuation, cooling, guidance and machine conditions should be evaluated more carefully.

Does the longer flute length equal the maximum drilling depth?

No. The drill point and the space required for chip evacuation must also be taken into account. Actual usable drilling depth depends on the complete machining setup.

Why not simply use the longest drill available?

Extra length is only useful when the application needs it. Unnecessary tool extension increases unsupported length and places greater demands on holding, alignment and machine rigidity. RONGKE recommends selecting the shortest tool that provides sufficient reach.

Is this drill suitable for recessed holes?

The long-series configuration can be considered when a recessed position requires additional tool reach. The actual recess, hole depth and available clearance should be checked before selecting the drill.

Is internal coolant included?

Internal coolant is not specified for the reference configuration. The cooling arrangement should be confirmed according to the workpiece and drilling conditions.

Can RONGKE make non-standard long drills?

Yes. In addition to standard cutting tools, RONGKE develops non-standard hole-processing tools. Buyers can provide the required diameter, overall length, flute length, workpiece information and machining conditions for evaluation.