Nail techs: How to choose the right e-file speed and grit

Finding the right speed and grit options for your electric, or e-file, can be confusing. Nail educator Katie Barnes explains how to select the right one for every service.

What is the best e-file speed for different nail services?

Slow speed: 1,000–10,000 rotations per minute (RPM)

Best for:

• Cuticle work with diamond cuticle bits (5,000–10,000 RPM)
• Natural nail preparation using a sanding band (1,000–5,000 RPM)

Medium speed: 10,000–15,000 RPM

Best for:

• General filing and shaping
• Refining natural nails
• Working on thinner enhancements such as gel polish or builder gel.

High speed: 15,000–35,000 RPM

Best for:

• Fast removal of gel and acrylic enhancements
• Reducing product bulk and thickness
• Callus removal during pedicures, where higher speeds help minimise heat build-up

Which e-file bit grit should I use for different nail services?

The grit of your e-file bit refers to the coarseness of its surface and determines its level of abrasiveness. The following grit ranges are commonly available:

Diamond cuticle bits

• Coarse grit: equal to a 140–170 grit nail file.
• Medium grit: equal to a 200–230 grit buffer.
• Fine grit: equal to a 400–grit file or buffer.
• Extra fine grit: equal to a 600-grit file or buffer.

Unlike carbide bits, diamond bits and sanding bands have an exact grit, meaning you can calculate exactly the level of abrasion you are using on the skin or nail plate to prevent damage.

Which e-file bit grit should I use?

The grit of an e-file bit refers to the coarseness of its surface and determines how abrasive it is.

Diamond cuticle bits

Diamond bits are available in several grit options:

• Coarse: Comparable to a 140–170 grit nail file
• Medium: Comparable to a 200–230 grit buffer
• Fine: Comparable to a 400-grit file or buffer
• Extra fine: Comparable to a 600-grit file or buffer

Unlike carbide bits, diamond bits and sanding bands have a precise grit rating, making it easier to control the level of abrasion and reduce the risk of damaging the natural nail or surrounding skin.

Carbide and silicone bits

Carbide bits are graded differently. Instead of using a traditional grit rating, their abrasiveness depends on the number, size and spacing of the cutting teeth (or flutes).

For example, a standard medium-grit, five-in-one straight-cut carbide bit with a 5.35mm flute size has 26 teeth on both the top and bottom. The wider-spaced teeth create a medium grit at the base, while the closer-spaced teeth provide a finer grit at the tip, allowing for multiple uses with a single bit.

Which sanding band grit is best?

Different sanding band grits are designed for different stages of a nail service:

• 150 grit (coarse): Best for quick and efficient product removal.
• 180 grit (medium): Ideal for refining the nail surface and working on both natural nails and enhancements. It can be used for natural nail preparation, although a 240-grit band is generally recommended for a gentler finish.

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Additional FAQs

Which grit is safe for natural nails?

Only fine grits should be used on natural nails to avoid damage. A 240 grit sanding band is the safest option for natural nail preparation, along with fine or extra-fine diamond bits (around 400–600 grit equivalent). Anything coarser than this increases the risk of over-filing the natural nail plate.

Can an e-file damage the nail plate?

An e-file can damage the nail plate if it is used incorrectly. This usually happens when too much pressure is applied, the speed is too high on natural nails, the bit is held in one area for too long, or the wrong grit or bit is used. When used correctly with proper control, speed, and technique, an e-file is a safe and effective tool.

Who should use an e-file?

E-files should only be used by trained professionals, as proper training is essential to understand correct speed, pressure, and bit selection. This ensures safe use of the tool and helps protect the natural nail and surrounding skin from potential damage.