Short, Rigid Drilling When Extra Length Gets in the Way
More drill length isn't always an advantage. Sutton stub drills give workshops a shorter, more rigid alternative when the hole is relatively shallow & the extra reach of a conventional jobber drill simply isn't needed. Sutton's D186 Blue Bullet range combines HSS construction with DIN 1897 stub geometry, making these compact twist drills particularly useful where access, controlled starting & resistance to drill deflection matter.
Rather than choosing a short drill simply because space is tight, consider what the reduced overall length does to the setup. Less unsupported drill length can make the tool more rigid, which is useful on suitable lathe work, fabrication components, repair jobs & hand-drilled holes where maintaining control at the cutting end is important.
When the job genuinely needs additional reach, Sutton Tools | Drills - Jobber provides the logical standard-length alternative. For holes where establishing an accurate starting position is the primary operation, Sutton Tools | Drills - Spotting TiNite serves a different purpose again.
What Are Sutton Stub Drills?
Sutton D186 Blue Bullet stub drills are short-format HSS twist drills manufactured to DIN 1897 geometry. Sutton describes the D186 as a rigid twist drill with self-centring point geometry, designed for use with suitable lathes & hand drilling machines.
The shorter construction distinguishes a stub drill from a conventional jobber-length drill. Reducing the distance between the chuck or holder & the cutting point creates a more compact setup, which can help limit unwanted flex when the additional reach of a longer drill offers no practical benefit.
Across the D186 specification, Sutton uses an R30 helix & identifies the maximum cutting depth as 3×D, meaning three times the drill diameter. Above 3 mm, the manufacturer specifies a 118° Form C point.
The Blu finish is also part of the D186 specification, but it shouldn't be confused with the TiAlN coatings used on other Sutton drill families. Product series matter: two drills can share the Sutton name while being designed around quite different materials, geometries & applications.
Why Choose Sutton Stub Drills?
Rigidity Where Reach Isn't the Priority
Imagine two drills of the same diameter, but one projects considerably further from the holder. When the deeper reach isn't required, the shorter tool gives the setup less unsupported length to work with.
That is the practical attraction of a stub drill. The format suits applications where a compact cutting tool is preferable to carrying unnecessary length into the operation.
Useful Access Around Machinery & Assemblies
Some drilling jobs simply don't offer much room between the chuck & the component. Machinery repairs, fabricated assemblies, fixtures & workshop modifications can place the hole in a position where tool length becomes part of the selection process.
A stub drill won't solve every clearance problem, but its shorter overall format can be useful when a standard-length drill makes the setup unnecessarily long.
A Different Tool From a Spotting Drill
Short does not automatically mean “spotting drill”.
A spotting drill is intended primarily to establish a controlled starting location for a subsequent drilling operation. A D186 stub drill is a twist drill intended to produce the hole itself within its specified depth capability.
Understanding that distinction helps avoid buying two visually compact drills for completely different reasons.
HSS Construction for the D186 Range
Sutton specifies the D186 in high-speed steel, with the series designated for ferrous materials. That is the specification to work from when evaluating this particular collection.
Where another material, coating or higher-performance cutting-tool construction is required, select the appropriate Sutton drill family rather than assuming every stub drill shares the same capability.
Common Applications
Lathe Drilling Where Tool Projection Matters
On a lathe, unnecessary drill projection can work against a compact setup. Sutton specifically identifies the D186 for suitable lathe applications, making the short format relevant where the required hole falls within the drill's working depth.
Toolholding still deserves attention. When the wider machining setup uses compatible ER tooling, Sutton Tools | Tool Holder - ER Collets provides a related Sutton machine-tool category for appropriate operations.
Shallow Holes in Fabricated Components
Not every plate, bracket or fixture needs a long drill. When the hole is relatively shallow, choosing a tool with far more flute length than the operation requires may offer no useful advantage.
The better approach is to match drill diameter & usable cutting depth to the component rather than defaulting automatically to the longest drill available.
Hand Drilling With a More Compact Tool
Sutton includes hand drilling machines among the intended equipment for D186. A shorter drill can make the overall setup more compact, which may be useful where the workpiece or surrounding assembly limits available space.
Secure workholding remains important. Where a component can be clamped rather than held by hand, Clamps & Vises can support a more controlled workshop setup.
Jigs, Fixtures & Repeat Workshop Work
A fixture with a series of shallow holes presents a different problem from a deep-hole drilling operation. Here, consistent positioning, suitable drill projection & repeatable workholding may matter more than maximum reach.
Before the first hole commits the component, Measuring & Layout Tools can help establish centres, spacing & reference dimensions.
Holes Requiring a Separate Finishing Operation
A drilled hole isn't always the final dimension. Some machining sequences deliberately leave material for a subsequent sizing or finishing operation.
Where the process calls for an existing prepared hole to be brought to final size with the appropriate tooling, Sutton Tools | Reamers provides a related hole-finishing range.
Product Selection Guide
Ask Whether You Actually Need the Extra Reach
This is the question that separates stub selection from habit.
If the required hole sits comfortably within the working depth of the short drill, extra length may offer little benefit. If the hole exceeds that capacity, choosing stub length purely for rigidity becomes the wrong trade-off.
For D186, Sutton specifies a maximum cutting depth of 3×D. A 6 mm drill therefore has a different working-depth limit from a 12 mm drill because the depth relationship is based on diameter.
Select the Diameter From the Component
Stub length doesn't change the fundamental sizing decision. The required finished hole still determines drill diameter.
Check the drawing, mating component, fastener requirement or machining allowance before selecting the cutter. If the hole will later be reamed, the drilling stage should be planned around that finishing operation rather than treating the drill diameter as the final dimension.
Confirm the Series Before Comparing Specifications
Sutton manufactures more than one type of stub drill. D186 Blue Bullet, D151 CNC & D177 DXS, for example, have different materials, finishes & point geometries.
Don't transfer a TiAlN or cobalt specification from another Sutton stub series onto D186 simply because both tools are short.
Consider the Holder & Available Clearance
Measure the setup, not just the component. Chuck length, tool projection, workholding & surrounding machine structure can all affect whether the drill reaches the hole comfortably.
A short cutter is most useful when its dimensions solve a real setup requirement.
Plan the Cutting Conditions Around the Operation
Drill diameter, workpiece material, machine, cutting depth & tool condition all influence how the operation should be approached. Where a suitable cutting fluid forms part of the setup, Alpha | Lubricants & Cutting Fluids provides related workshop consumables.
Expert Tips
Use Short Length Deliberately
Choosing stub length should be a decision, not an accident. If 3×D provides enough working depth, the compact format can make sense. If the hole needs more reach, move to a drill designed to provide it rather than pushing a stub drill beyond its intended depth.
Keep Projection Sensible
A short drill loses some of its practical advantage if it's held with unnecessary projection from the chuck or holder. Seat & secure the tool correctly for the equipment being used while maintaining the clearance the job requires.
Don't Let “Self-Centring” Replace Layout
Sutton describes the D186 with self-centring point geometry, but that doesn't make measurement optional. Accurate hole location still depends on proper setup, reference dimensions & workpiece control.
Treat 3×D as a Limit, Not a Challenge
Maximum cutting depth isn't a target you need to reach on every hole. A shallow 4 mm hole with an 8 mm drill is still a perfectly legitimate reason to choose a short-format tool when the rest of the setup benefits from it.
Check the Flutes Before the Next Component
Repeated shallow drilling can make it easy to focus only on the point. Chips, built-up material or cutting-edge wear deserve attention before the next component goes under the drill.
For broader workshop tool-care practices, How To Clean Your Gear Without Ruining It covers sensible maintenance without turning routine cleaning into tool damage.
Compare the Tool to the Job Before Replacing It
Poor drilling performance isn't always proof that the drill format is wrong. Workholding, projection, cutting conditions, tool wear & material can all change the result.
The Black Print: Blade Sharpening 101 Sharpen Or Replace explores the broader workshop judgement around worn cutting tools & replacement.
