Brazed Single Flute Gun Drill — Deep Hole Drilling Ø3–45mm | Tungstool

Gun drill structure

Brazed gun drills made by Tungstool are a type of gun drill often used for deep holes. When set up correctly, they can make very precise holes (like IT7 grade) in just one pass.

Gun drilling itself is a highly efficient and effective way to drill deep holes. It works well not only on dedicated gun drilling machines but also on many CNC machines that work with metal.

Brazed gun drills are usually made of 3 parts: the cutting tip, the long drilling shank with chip removal area and drive.

Tungstool Cutting Tools Co., Ltd. specializes in making and developing gun drills. We use only the best quality tungsten carbide, shank tubes, and drivers. This results in high-quality gun drills. We fully control the entire manufacturing process, ensuring consistent drill bit quality and reliable supply.

Our brazed gun drills come in sizes from 3mm to 45mm in diameter, with maximum lengths up to 6000mm.

Gun drill with short length

Normally, we call gun drills under 600mm in length “short drills”. They are widely used for metal parts like shafts.

As CNC drilling machines become more common, short drills are being used more and more in mold making. This is especially true for CNC machines with automatic tool changers. Using short gun drills on these machines significantly boosts efficiency.

Tungstool Cutting Tools Co., Ltd. has focused a lot on developing short gun drills. We help customers solve deep hole drilling problems. Because of this, short gun drills are now used more widely and work more efficiently.

Long-tip design and processing

Long-tip carbide gun drills offer high precision in hole diameter, straightness, and smoothness (surface finish). They are used for making auto shafts and cross holes in molds and hot runners.

However, making these long-tip carbide drills requires very precise grinding and is a more complex process. This makes them more expensive than standard gun drills.

Because of their high precision, they are mainly used in demanding applications like auto shafts and hot runners.

Tip types / hole bottom shape

Tungstool’s gun drills can create different hole bottom shapes.
We’ve developed drills for flat-bottom holes, holes with spherical bottoms, and angled-bottom holes based on market needs.
We can also custom-make special drill tips to produce unique hole bottom shapes for your specific requirements.

Flat bottom

Spherical bottom

Angled bottom

Coating

Coatings for gun drills have developed quickly in China in recent years.

Tungstool is working with a globally recognized coating company. This partnership lets us offer a wide range of coatings to meet different hole-making needs.

We also keep some standard coated carbide tips in stock. This means we can deliver them to you fast.

Technical Specifications

Parameter	Specification
Diameter Range	Ø3 – Ø45 mm
Maximum Length	Up to 6000 mm (6 meters)
Depth-to-Diameter Ratio	Up to 200×D (depending on diameter)
Tolerance Achievable	IT7 (one-pass), IT6 with finishing pass
Tip Material	Solid carbide (K10/K20 grade), brazed on alloy steel shank
Shank Type	Ground cylindrical shank with drive flat
Coolant	Internal through-tool coolant (single channel, V-flute)
Coating Options	TiAlN, TiCN, AlCrN, uncoated
Hole Bottom Shapes	Flat, spherical, angled, or custom

Industries & Applications

Brazed single-flute gun drills are the go-to solution for deep hole machining across demanding industries:

Industry	Typical Application
Automotive	Crankshaft oil holes, connecting rod bores, fuel injector channels
Aerospace	Landing gear strut bores, hydraulic manifold channels, engine shaft cooling holes
Mold & Die	Cooling channels, ejector pin holes, hot runner bores
Oil & Gas	Downhole tool bores, valve body channels
Medical	Surgical instrument cannulations, implant coolant channels
General Engineering	Hydraulic manifold channels, long shaft bores, spindle cooling holes

Frequently Asked Questions

Q: What is the advantage of a brazed gun drill over a solid carbide gun drill?

Brazed gun drills combine a high-performance carbide cutting tip with a tough alloy steel shank. This gives you the cutting performance of carbide at the tip where it matters, while the steel shank absorbs vibration better and costs significantly less than a full solid carbide drill — especially in longer lengths.

Q: What hole tolerance can a Tungstool gun drill achieve?

Our brazed gun drills routinely achieve IT7 tolerance in a single pass. With optimized cutting parameters and a finishing pass, IT6 tolerance is achievable. Every drill is inspected before shipment.

Q: Can you re-tip or regrind our existing gun drills?

Yes. Our re-tipping service replaces worn carbide tips on your existing shanks. After precision alignment and testing, re-tipped drills deliver near-new performance at a fraction of the cost.

Q: What is the minimum order quantity?

No minimum. Order a single drill for testing, or place production quantities. We welcome both sample and volume orders.

Q: What information do you need to quote a custom gun drill?

Provide: (1) hole diameter and tolerance, (2) total drilling depth, (3) workpiece material, (4) machine type and coolant pressure available, (5) hole bottom shape (flat/spherical/angled). A drawing is helpful but not required.

Regrinding service

Re-tipping service lets customers reuse gun drill shanks and drivers when only the carbide tip wears out. We braze new carbide tips onto original shanks, then perform precision alignment and rigorous testing. These re-tipped drills deliver nearly identical performance to new drills while cutting costs a lot and reducing environmental waste.