Guide · Bits and fit
Nail drill bit shapes and grits
What barrel, cone, flame, ball, safety and 5-in-1 bits are for, how makers label grits and cuts, and a small starter set that fits a 3/32-inch handpiece.
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Short answer
Shape decides where a bit works; grit or cut decides how fast it removes material. A barrel files flat surfaces and shortens, a cone or flame reaches the sidewalls and cuticle area, a safety bit has a smooth top for work near the skin, and a mandrel holds disposable sanding bands. Coarseness names are each maker's own: KUPA, for example, sells carbide in five cuts from fine to 2X-coarse and diamond in three grits.[1][2]
Shapes and what they are for
| Shape | What it looks like | Typical use |
|---|---|---|
| Barrel | A cylinder with a flat end | Filing the top surface, shortening, shaping the free edge; a small barrel reaches tighter areas |
| Safety bit | A barrel with a smooth, rounded top | Surface work close to the cuticle, where the top should not cut |
| Cone | Tapers to a narrower tip | Sidewalls and the area under the free edge |
| Flame | A pointed, flame-like head | Cuticle area and lifting product at the edges |
| Ball | A small sphere | Cuticle area and small details |
| 5-in-1 carbide | A tapered carbide head shaped for several jobs | Shaping and removing acrylic or hard gel with one bit |
| Mandrel and sanding bands | A metal post that holds a disposable abrasive sleeve | Surface filing and removal; the band is replaced, the mandrel is kept |
These uses are general descriptions, not maker rules. Each maker names and shapes its bits a little differently, so read the maker's description of the bit you are buying.
Some maker examples:
- KUPA says its diamond small barrel bit can be used with any 3/32-inch e-file handpiece.[2]
- KUPA's comprehensive bit kit includes a carbide safety bit and a 3/32-inch mandrel with sanding bands.[3]
- Medicool designed its 5-in-1 carbide bit (CC22) to cut both clockwise and counter-clockwise.[4]
Grits and cuts
Coarseness is labeled two ways:
- Diamond bits use grits. KUPA sells its diamond small barrel in fine, medium and coarse.[2]
- Carbide bits use cut grades. KUPA sells its 3-in-1 carbide bit in fine, medium, coarse, extra-coarse and 2X-coarse.[1]
We found no cross-brand standard for these names. One maker's "medium" can differ from another's, and we found no verified color-band convention either. Compare grits within one brand, not across brands.
As a general rule, finer grits and cuts suit the natural nail and finishing, and coarser ones suit removing product. Start finer than you think you need.
Fit and direction come first
A shape is only useful if the bit fits and cuts in the direction you work.
- Fit. Buy the shank size your handpiece maker states, usually 3/32 inch. Some bits also have machine exceptions: Medicool says its 5-in-1 carbide bits do not work with its File Stream, Vac File or Pro Vac File Classic machines.[4] See do all bits fit all drills.
- Direction. A standard carbide bit cuts one way. Left-handed techs need a two-way or left-hand bit. See forward and reverse.
A small starter set
- A fine diamond small barrel or flame for prep and the cuticle area.
- A safety bit for surface work near the skin.
- A carbide barrel or 5-in-1 in fine or medium for shaping and removal.
- A mandrel with a pack of sanding bands, if you prefer disposable abrasives.
Two carbide examples for the list above: MelodySusie says all its bits have a 3/32-inch shank.[5]
Next
Questions
What is a safety bit used for?
Surface work close to the cuticle. Its smooth, rounded top is meant not to cut, so the side of the barrel does the work. KUPA's bit kit, for example, includes a carbide safety bit.[3]
Is there a standard nail bit grit chart?
We found no cross-brand standard. KUPA sells diamond bits in fine, medium and coarse and carbide in five cuts up to 2X-coarse, but other makers use their own names, so compare within one brand.[2][1]
What does a 5-in-1 bit do?
It is a carbide bit shaped to do several shaping and removal jobs. Medicool's 5-in-1 (CC22) is also designed to cut in both directions, for right- and left-handed techs.[4]
How many bits does a beginner need?
A few: a fine diamond for prep, a safety bit, and a fine or medium carbide barrel or 5-in-1 for shaping. Add shapes as your work needs them.