Bit type
Diamond nail drill bits: grits, shank, lifespan and fit
What a diamond nail drill bit is, the grits makers sell, KUPA's 3/32-inch fit statement, Medicool's lifespan estimate and the Prop 65 notice.
Also listed as diamond nail drill bit, diamond grit bit
Short answer
A diamond bit is coated with abrasive diamond grit and graded by grit, not cut. KUPA says its diamond small barrel fits any 3/32-inch e-file handpiece and sells it in fine, medium and coarse. Medicool estimates diamond bits last about 6-12 months in daily professional use, the longest of the materials it lists.
Key facts
- Head shape
- Many shapes; KUPA's example is a small barrel[1]
- Shank
- 3/32 inch (KUPA)[1]KUPA says its diamond small barrel can be used with any 3/32-inch e-file handpiece.
- Grits or cuts
- Fine, medium, coarse (KUPA diamond small barrel)[1]Grit names are each maker's own scale.
- Lifespan (claimed)
- About 6-12 months in daily professional use (Medicool)[3]Medicool's estimate, not a standard.
- Maker examples
- KUPA diamond small barrel; diamond bits in KUPA's comprehensive bit kit[1][2]KUPA's kit was sold out on 2026-10-07.
- Fit caveats
- KUPA's fit statement covers 3/32-inch handpieces, not chucks labeled 2.35 mm[1][4]3/32 inch is 2.38125 mm.
- What no source confirms
- How diamond compares with carbide or ceramic for heat[3]We found no comparative heat measurement across bit materials.
Watch out for
- 2.35 mm is not 3/32 inch. KUPA's "any 3/32-inch handpiece" statement does not cover chucks labeled 2.35 mm, and no maker statement we found says the two labels are interchangeable.
- Prop 65 notice. KUPA's diamond small barrel page carries a California Proposition 65 warning.
- Worn grit means more heat. Medicool says dull bits cause extra heat and pressure; replace a bit when it stops cutting cleanly.
Compare materials in carbide vs diamond vs ceramic nail drill bits, and shapes in the barrel bit page.
Questions
How long does a diamond nail drill bit last?
Medicool estimates about 6-12 months for diamond bits in daily professional use, longer than its estimates for carbide (2-4 months) and ceramic (3-6 months). It is Medicool's estimate, not a standard.[3]