Equipment type
E-file handpieces: chuck, 3/32 fit, size, weight and care
What an e-file handpiece is, the size, weight and speed figures makers publish, which controllers a handpiece fits, and how makers say to care for one.
Also listed as nail drill handpiece, handpiece
Short answer
The handpiece is the pen-shaped part you hold. Its motor spins the bit, which a chuck grips by the shank. KUPA lists its KP-55 at 5.35 in long, 0.78 in in diameter and 5.6 oz with a locking chuck for 3/32-inch bits. A handpiece is not universal: KUPA publishes which of its handpieces work with the Passport NEXT controller.
Key facts
- What it does
- The part you hold: its motor spins the bit, gripped by a chuck[1][2]KUPA's KP-55 uses a locking chuck; Medicool's 35K Portable uses a twist-lock chuck.
- Bit shank
- 3/32 inch (KUPA KP-55 and Companion, Medicool 35K Portable)[1][3][2]Follow the handpiece maker's stated size.
- Speed (claimed)
- 30,000 RPM (KUPA KP-55, Companion); 35,000 RPM (Medicool 35K Portable)[1][3][2]Maker figures, not measurements under load.
- Torque published
- 4.8 N-cm (Medicool 35K Portable); no torque figure in KUPA's handpiece specs[2][1][3]Medicool states no test method. KUPA's KP-55 and Companion specs list speed, size and weight only.
- Handpiece size
- KP-55: 5.35 in, 0.78 in diameter, 5.6 oz; Companion: 4.75 in, 0.8 in, 5 oz; KP-65: 4.24 in, 5.36 oz; KP-60: 4.25 in, 4.23 oz; Medicool 35K Portable: 4.9 oz[1][3][2]Maker specs. KUPA gives 0.8 in diameter for the KP-60 and KP-65.
- Warranty
- Not confirmedWe did not verify a warranty term for a handpiece sold on its own.
- What no source measures
- Heat, vibration and runout[1]KUPA's "virtually no vibration" is a maker claim. We found no independent measurement of handpiece heat or vibration.
Watch out for
- Handpieces are matched to controllers. KUPA lists the KP-36, KP-50, KP-55, KP-60, KP-65 and Companion handpieces as compatible with the Passport NEXT. Use the controller maker's list instead of assuming any handpiece fits any box.
- Never submerge a motorized handpiece. Medicool says to wipe it down instead.
- Models get discontinued. KUPA marked the KP-55 as sold out and being discontinued in January 2026, so check that a replacement handpiece is still made for your controller.
- Repairs go through the maker. KUPA runs an authorized repair-center locator and invites owners without a nearby center to contact KUPA for service.
Handpiece weight is one of the few comparable numbers makers publish. Between KUPA's listed handpieces it runs from 4.23 oz (KP-60) to 5.6 oz (KP-55).
Hot handpiece? Read why a nail drill handpiece gets hot and nail drill care and repairs.
Questions
Can I use any handpiece with any e-file control box?
Do not assume so. KUPA publishes a list of handpieces compatible with its Passport NEXT controller (KP-36, KP-50, KP-55, KP-60, KP-65 and Companion). Check the controller maker's own list before buying a spare or replacement handpiece.[3]
Can I wash an e-file handpiece?
Medicool says motorized handpieces should never be submerged in liquid and should be wiped down instead. Follow your own maker's care instructions.[4]
Where do I get a handpiece repaired?
Ask the maker first. KUPA runs an authorized repair-center locator on its own site and invites owners without a nearby center to contact KUPA for service.[5]