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Xiaomi’s Mijia Rotary Tool Kit—called the Mijia electric grinding pen in some regional material—is a compact, rechargeable rotary tool for detail engraving, grinding, polishing and drilling. It has a 2 cm-diameter anodised-aluminium body, a brushless motor rated for 15,000–22,000 rpm, and a kit of 16 bits with 2.35 mm shanks. Xiaomi claims up to 60 minutes of continuous use per full charge under controlled conditions; actual runtime depends on use.
What is the Mijia electric grinding pen?
Xiaomi calls it the Mijia Rotary Tool Kit; Xiaomi Taiwan uses the name 米家電磨筆, or Mijia electric grinding pen. It is a small rotary tool intended for fine-detail work rather than a general-purpose drill. Xiaomi lists engraving, grinding, polishing and drilling among its uses, and illustrates wood carving, sanding wood, metal or models, drilling holes in pendants, and polishing jade, silver and small handheld objects. These are Xiaomi’s stated applications, not independent performance test results.
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What are its size, motor and speed?
| Specification | Xiaomi’s stated detail |
|---|---|
| Body | 2 cm diameter; anodised aluminium alloy |
| Motor | Brushless coreless motor |
| Speed | 15,000–22,000 rpm |
| Controls | Power button and speed-adjustment knob |
| Weight | Approximately 310 g in Xiaomi’s product/case presentation; the page does not establish this as the bare tool’s weight |
The slim pen form and small diameter are intended to make detailed work easier to handle. Xiaomi describes the motor as delivering up to 22,000 rpm; that is a manufacturer specification, not an independently measured result.
How long does the battery last, and can it run plugged in?
The tool has an 800 mAh lithium battery. Xiaomi states up to 60 minutes of continuous operation after a full charge in controlled tests, and notes that ambient temperature, workload and other factors affect actual runtime. It can also operate while connected to power for longer sessions, but it does not charge while running: charging starts after the tool stops. Xiaomi recommends a 5 V / 3 A input when the low-battery indicator flashes red.
#1 Best Overall
- Push pop-up, magnetic Storage - Classic award-winning design: The Mi Precision Screwdriver has won five international design awards; namely the iF, Red Dot, Japan Good Design, IDEA and Chicago Good Design awards. The Xiaomi Electric Precision Screwdriver uses the same popup design, featuring a convenient, push-to-release mechanism.
- Electric precision screwdriver, enhanced precision efficiency: Thanks to the powerful magnetic motor with a speed of up to 200rpm. and the all-metal gearbox, the screwdriver has a screwdriving bit concentricity of no more than 0.2mm when rotating, for greater precision efficiency.
- Compact design with an extra-long battery life, 400+ precision screws on one full charge: The screwdriver has a shaft diameter of just 16.4mm. The built-in rechargeable lithium battery is powerful and long-lasting and can process 400+ precision screws on one full charge.
- 24 x S2 steel precision screwdriving bits in 9 major types: The 24 x high-quality S2 tool steel screwdriving bits are durable and tough and have a hardness of up to 60HRC. The 24 types of precision screwdriving bit are ideal for dismantling and assembling most standard electronics and new small household appliances.
- 6 commonly used 45mm long screwdriving bits for complex deep-hole applications: 6 commonly used screwdriving bits out of the 24 are 45mm long for use in a wide range of complex applications, such as deep holes and narrow spaces. (Xaomi Quality Trustworthy. Only “Xiaomi US” official store provide 13 months warranty for electric screwdriver.)
Which bits fit the Mijia electric grinding pen?
The kit includes 16 bits, all with 2.35 mm shanks. Xiaomi’s listed accessories include a wool polishing wheel, twist drill, diamond grinding bits, abrasive grinding bits, rubber grinding heads and wool grinding heads. The bits are consumables, so replacements may be needed as they wear.
Do not assume that every rotary-tool accessory fits. Before buying or using a replacement, check that its shank matches the chuck and that its rated speed is at least the tool’s maximum speed of 22,000 rpm. Inspect each accessory before use, as the manual advises.
Rank #2
- Note about Compatibility: The precision-machined F2 Master collet accepts 3/32" (2.3mm) accessories
- Whisper-Powerful: The Fanttik F2 Master features a hollow cup motor that reduces noise by 30% compared to standard motors. It delivers stronger performance and less heat. 5 adjustable speed settings make it easy to handle various precision tasks
- Revostor Hub: No more searching for attachments! The F2 Master features a 360° rotating magnetic stand with 35 organized accessories (3/32" / 2.3mm), making DIY tasks like grinding, polishing, drilling, engraving and 3D printing finishing easy and convenient
- Mini & Portable: Weighing just 0.22 lb, its lightweight design is perfect for on-the-go creativity. The durable aluminum case resists rust and features a one-click pop-out design for quick and easy tool access
- Stylish & Practical: Seamless integrated speed control button, waterproof and dustproof for easy cleaning, adaptable to any work environment. Innovative LED speed indicator displays real-time settings for precise operation at every step
What should you know before using it?
- Wear suitable eye or face protection. Depending on the work, use dust and hearing protection, gloves and protective clothing.
- Inspect the bit for damage and confirm that it is correctly fitted before starting.
- Secure small workpieces as appropriate, keep bystanders clear, and avoid using the tool near flammable materials.
- Do not use liquid coolants.
- Work on valuable objects can cause irreversible damage; Xiaomi advises professional supervision for such jobs.
Are the launch prices current?
No. IT Home reported on 17 August 2024 that China sales were scheduled to begin at 8 p.m. that day, listing a price of 199 yuan and a reservation price of 179 yuan. Those are historical China launch-period figures, not a statement of current price or availability. Xiaomi’s product page also says packaging with a multilingual information label would be added starting 15 July 2026, with either packaging version potentially shipping during the transition; this does not establish a hardware revision.
Quick Recap
Best Value
- 【ONLY FOR LIGHT-DUTY WORK & SUPPORT RESOURCES】 1‑YEAR PRODUCT WARRANTY. PLEASE CONTACT CUSTOMER SERVICE FOR ANY QUALITY ISSUES, WE PROVIDE 24‑HOUR SUPPORT FOR YOU.
- 【RICH 448‑PIECE ACCESSORY SET】The EWORK cordless rotary tool kit includes the 4V electric rotary tool, a USB charging cable, and 448 rotary tool accessories and rotary tool bits. You get : 198pcs surface sanding kit, 112pcs professional grinding kit, 74pcs heavy-duty cutting kit, 37pcs polishing kit, 10pcs precision carving kit, 6pcs drilling kit, 9pcs essential mounting & utilities, 2pcs tool & charging cable. this set functions as an all-in-one rotary tool accessory kit for any project.
- 【5‑SPEED ADJUSTABLE SPEED CONTROL】 This mini rotary tool supports variable speed adjustment from 8000‑23000 RPM for flexible operation. Lower speed settings suit polishing work while higher speeds apply to cutting tasks. Simple dial adjustment is friendly for new DIY users.
- 【LIGHTWEIGHT PEN‑STYLE ERGONOMIC GRIP】 Weighs only 140g with pen‑grip construction to reduce hand fatigue during long‑time operation. Built‑in LED light improves visibility for resin engraving, jewelry polishing and model sanding in dim work environments.
- 【PRACTICAL DIY GIFT CHOICE】 This cordless engraving pen enables handmade craft creation for daily use. It serves as a thoughtful gift choice for DIY enthusiasts on birthdays, Father’s Day, Thanksgiving and other holiday occasions for handicraft‑making hobbies.
Rank #4
- Note about Compatibility: The precision-machined F2 Master Kit collet accepts 3/32" (2.3mm) accessories
- Precision Control & Quiet Operation: This cordless rotary tool provides smooth, adjustable performance with quiet operation at 32 dB and reduced vibration, supporting greater accuracy and comfort for detailed cutting, grinding, and polishing
- All‑in‑One Storage: The mini rotary tool kit includes a premium flip‑lid storage case with magnetic compartments to keep accessories neatly organized, plus dedicated space for bits, and in-case charging for an efficient, clutter-free workflow
- Seamless Pressure‑Sensitive Speed Control: Designed as a slim engraving pen, the lightweight aluminum body(0.22 lb) fits naturally in hand for extended use. Pressure-responsive speed control supports smoother operation and improved handling for fine engraving and detail work
- Clear LED Status & Work Lighting: Built-in LED indicators display battery status, speed levels, and overload alerts, while the integrated work light enhances visibility on fine details for more controlled and confident operation
Rank #3
- Powerful Magnetic Motor & Ultra-high Torque: Xiaomi electric screwdriver uses a strong magnetic motor with up to 5 N.m torque. The powerful magnetic motor and all-metal gearbox makes installation of light fixtures, home furnishings, electronics and other items simple and easy
- Cordless and Portable: Xiaomi electric screwdriver rechargeable comes with High-capacity 2000 mAh battery with USB-C charging port for cordless portability. Insulated, flame-retardant, removable battery case design.
- S2 High-quality 12 pcs Steel Bits with Added Extension Rod: The 12 high-quality S2 alloy steel bits are hard, durable and have a high-precision fit. Use the 60 mm added extension rod for hard-to-reach places—perfect for most at-home needs
- One-piece Body Design: Patented design of Mi Cordless Screwdriver is aesthetically pleasing and reliable thanks to the one-piece, screw-free design. High-quality engineering plastic, 2-coat lacquer finish for a comfortable grip, with anti-dirt and anti-rust treatment.
- Innovative Dial & Convenient to Use: One-hand spin-direction toggle. The innovative three-shift dial makes it easy to use the screwdriver with one hand and to work with greater precision. Three LEDs form a circular light strip with automatic lighting.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
