Best #38 Drill Bits for Metalworking and Precision Projects
The best #38 drill bit depends on the material and the job: cobalt bits are suited to tougher metals, while standard high-speed steel options cover lighter drilling and general DIY. For threading 5-40 holes, choose a tap-and-drill kit instead of a standalone bit. The five options below compare material, pack size, point design, and intended use so you can match a bit to your work.
| Product | Best For | Notable Feature |
|---|---|---|
| Drill America D/ACO | Repeated drilling in hard metals | Cobalt steel, 12-pack |
| HARFINGTON Cobalt | Metal drilling with a split point | 118° split-point tip, 12-pack |
| PATIKIL M2 HSS | Hard-metal drilling and spares | 135° split point, 12-pack |
| PATIKIL 4341 HSS | Light-duty mixed-material projects | Five bits, gold finish |
| RURITKIT 5-40 Set | Drilling and tapping 5-40 threads | Includes #38 bit and tap |
Drill America D/ACO Cobalt Drill Bit
This 12-pack is best for users who need multiple #38 bits for work involving harder metals. Drill America’s cobalt steel is intended to improve performance when cutting materials such as stainless steel and nickel alloys. The bits have round shanks, which support use with a wide variety of toolholding systems.
The gold oxide finish is a thin surface treatment used to identify cobalt steel tools; the listed product information says its performance is similar to uncoated tools. Choose this option when the cobalt material is the priority. The listing does not provide a point-angle or bit-length specification, so check those details if they are essential to your setup.
HARFINGTON Cobalt Bits With Split Points
HARFINGTON’s 12-pack is best for drilling stainless steel, cast iron, and other tough materials when a split-point tip is desirable. Each bit has a listed diameter of 0.1015 inch, a 36 mm drilling length, and a 63 mm overall length. Its cobalt-alloy high-speed steel construction is described as wear-resistant and suited to high-temperature cutting conditions.
The 118° split-point design is intended to help center the bit and reduce movement at the start of drilling. Spiral flutes help carry chips away from the work area. Choose this pack for a stated combination of cobalt material, defined dimensions, and split-point geometry. The product information does not specify a recommended speed for each material, so select operating conditions carefully.
PATIKIL M2 HSS Bits For Hard Metal
This 12-pack is best for users who want M2 high-speed steel bits for a range of metal-drilling tasks. The bits measure 0.1015 inch in diameter, with a 37 mm flute length and 64 mm overall length. Their 135° split points distinguish them from the 118° options in this comparison, while the black nitriding finish is listed as improving wear and corrosion resistance.
The stated applications include low- and medium-carbon steel, alloy steel, stainless steel, cast iron, and aluminum alloys. For harder materials, the product information recommends coolant to reduce wear. Choose these if you need a larger supply and a split-point bit intended for medium- to high-hardness metal. Avoid assuming the finish removes the need for suitable cutting conditions.
PATIKIL 4341 HSS Bits For Mixed Materials
This five-pack is best for light-duty projects involving thin metal or a mix of materials. The 4341 high-speed steel bits have a 2.578 mm cutting diameter, 35 mm flute length, 63 mm overall length, and 118° point. The listing names low-carbon steel, aluminum alloy, brass, cast iron, medium-carbon steel, stainless steel, acrylic, plastic, and wood among suitable materials.
The gold finish is described as helping resist wear and corrosion. Choose this set if you want several bits for general work rather than a 12-pack intended for heavier ongoing use. For thicker metals, the manufacturer’s guidance calls for low RPM and flood coolant; this is not the pick to treat as a high-speed solution for thick stock.
RURITKIT 5-40 Tap And Drill Set
This kit is best for creating or repairing 5-40 threads because it includes both a #38 drill bit and a matching 5-40 UNC tap. The components are listed as M2 steel with a titanium-plated finish, and the set comes in a storage box. The tap can be driven by hand or machine and is designed for through-holes or shallow blind holes.
The listed applications include metals such as stainless steel, cast iron, aluminum, and bronze, as well as hard plastics. Choose this set when the goal is threading, not simply making an unthreaded hole. Its usefulness is specific to the included 5-40 tap size, so choose a different setup if your project requires another thread specification.
Buying Guide: How To Choose A #38 Drill Bit
What size is a #38 drill bit?
A #38 bit is approximately 0.1015 inch, or 2.578 mm, in cutting diameter, according to the product specifications provided here. It is a numbered drill size, so verify the required hole diameter before buying rather than substituting a nearby fractional size.
Which material is best for the workpiece?
Cobalt bits are a relevant choice for tougher metals, including stainless steel and nickel alloys. M2 high-speed steel offers a general-purpose option, with some listed models specifically intended for harder metals. The 4341 HSS option is positioned for light-duty work across thin metals and materials such as wood, plastic, and acrylic. Always follow the bit maker’s guidance for the material being drilled.
Does point angle matter?
These products include 118° points and 135° split points. The listings describe split-point designs as helping with positioning or centering. Compare point geometry if starting-hole control is important, and make sure the bit’s dimensions suit the depth of your work.
Should I buy a single bit or a pack?
A multi-pack is practical when you need spares or expect repeated use. The listed options range from five-bit sets to 12-packs. A tap-and-drill kit is more suitable when you need to produce threads, since it includes a tap as well as the #38 drill bit.
Frequently Asked Questions
Can a #38 drill bit be used for a 5-40 tap?
The RURITKIT set pairs a #38 drill bit with a 5-40 UNC tap. Use a kit or reference that explicitly matches the required thread specification for your project.
Can I drill stainless steel with a #38 bit?
Several listed products identify stainless steel as a suitable material, including the cobalt and M2 HSS options. Use appropriate speed and cutting conditions; the PATIKIL listings recommend coolant for harder or thicker metal applications.
Are all #38 bits the same length?
No. The listed products have different flute and overall lengths. Compare those measurements with the hole depth and available clearance for your work.
What is the difference between cobalt and HSS bits?
Cobalt steel contains more cobalt than standard high-speed steel and is presented here for improved performance in harder metals. HSS options vary by grade and intended use, so check the specific product material and application notes.