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Mini Brass Drill Chuck Shaft Adapter – 4.05mm for 550 / 775 Series DC Motors & DIY CNC
Mini Brass Drill Chuck Shaft Adapter – 4.05mm for 550 / 775 Series DC Motors & DIY CNC
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The Mini Brass Drill Chuck Shaft Adapter – 4.05 mm is engineered for mid-range DC hobby motors — including select 550 and 775 series motors — commonly used in DIY CNC routers, desktop engraving machines, and lapidary grinding setups. Precision-machined brass construction ensures a secure, low-runout fit between your motor shaft and collet chuck — no custom machining required.
Key Features
Precision-Machined Brass Construction
Solid Brass Body: Machined to tight tolerances for a secure, wobble-free fit between your 4.05 mm motor shaft and collet chuck — minimizing runout and vibration at operating RPM.
Knurled Grip Surface: Textured exterior for positive hand-tightening and secure seating during chuck installation and removal.
4.05 mm Shaft Fit
Compatible with 550 and 775 series DC hobby motors commonly used in DIY CNC builds, desktop engraving machines, and lapidary grinding setups.
Output bore: 3.17 mm (1/8") — compatible with our Mini Brass Collet Chuck and most third-party mini brass chucks accepting a standard 1/8" input bore.
Universal Chuck Compatibility
Designed to pair directly with our Mini Brass Collet Chuck (3.17 mm bore) — sold separately or as part of the Full Collet Chuck Set.
Also compatible with most third-party mini brass chucks accepting a standard 3.17 mm (1/8") input bore.
Applications
DIY CNC & Engraving Machines
CNC Router Spindles: Attach a collet chuck to 550/775 series DC motors for improved tool grip on engraving bits and routing tools in desktop CNC builds.
Desktop Engraving: Secure, low-runout chuck interface for engraving machines using mid-range DC motors with 4.05 mm shafts.
Lapidary & Glass Finishing
Motor Shaft Upgrades: Repurpose existing 550/775 series motors for lapidary grinding and glass carving setups with a collet chuck attachment.
Precision Drilling in Hard Materials: Pair with diamond hollow drill bits for clean, chip-free holes in gemstones, glass, and ceramic.
Jewelry Making & Bench Work
Mid-Range Motor Integration: Connects 4.05 mm shaft motors to collet chucks for use with fine carbide burs and engraving bits in jewelry fabrication and stone setting.
Technical Specifications
| Specification | Detail |
|---|---|
| Shaft Bore (Input) | 4.05 mm |
| Chuck Bore (Output) | 3.17 mm (1/8") |
| Material | Solid Brass |
| Compatible Motor Types | 550 / 775 series DC hobby motors, DIY CNC spindles |
| Typical Applications | DIY CNC, engraving, lapidary grinding, jewelry, glass finishing |
Comparison: Shaft Adapter vs. Full Chuck Set
| Feature | Shaft Adapter (This Listing) | Full Collet Chuck Set |
|---|---|---|
| Contents | 1 × 4.05 mm shaft adapter | Chuck body + 11 collets + 1 adapter + hex key |
| Best For | Replacing or adding a 4.05 mm adapter to an existing chuck | Complete micro-drilling solution from scratch |
| Chuck Required | Yes — sold separately | Included |
Installation
Press the 4.05 mm adapter firmly onto your motor shaft.
Thread or press the collet chuck body onto the adapter’s output end (3.17 mm bore).
Insert the appropriate collet, load your drill bit or bur shank, and tighten with the hex key before operating.
Best Practices
Verify your motor shaft diameter with calipers before ordering — nominal sizes (e.g. “4 mm”) may vary slightly by manufacturer.
Ensure the adapter is fully seated and secure before operating at high RPM to prevent runout or chuck wobble.
When drilling hard materials such as stone or glass, pair with diamond-coated drill bits and use water as a coolant to extend bit life.
Compatible Collet Sizes
This adapter is compatible with the following collet sizes when used with our Mini Brass Collet Chuck:
| Collet Size | Clamping Range |
|---|---|
| 0.5 mm | 0.2 – 0.5 mm |
| 0.8 mm | 0.3 – 0.9 mm |
| 1.0 mm | 0.7 – 1.1 mm |
| 1.2 mm | 0.8 – 1.3 mm |
| 1.6 mm | 1.3 – 1.7 mm |
| 1.8 mm | 1.4 – 1.9 mm |
| 2.0 mm | 1.8 – 2.1 mm |
| 2.4 mm | 2.1 – 2.5 mm |
| 3.0 mm | 2.5 – 3.0 mm |
| 3.2 mm | 2.8 – 3.2 mm |
Related Tools
Mini Brass Collet Chuck Set — The matching chuck body and collet set for use with this adapter.
Diamond Wire Hollow Drill Bits — Ideal for drilling gemstones, glass, and ceramic with your chuck setup.
Sintered Diamond Core Drills — For larger bore drilling in hard stone and glass with superior longevity.
Machine Accessories — Full range of shaft adapters, backing plates, and motor accessories.
Jewelry Making Tools — Burs, mandrels, and precision tools for bench jewelers and stone setters.
Why Choose This Shaft Adapter?
Precision Fit: Machined to tight tolerances for a secure, low-runout connection between your 4.05 mm motor shaft and collet chuck.
Mid-Range Motor Coverage: Covers the 550/775 series DC motor shaft diameter — the workhorse of DIY CNC and desktop engraving builds.
Immediate Upgrade: Extend the utility of your existing collet chuck to a 4.05 mm motor platform without sourcing custom parts.
Ideal For: DIY CNC builders, desktop engraving enthusiasts, lapidary artists, jewelry makers, and makers upgrading or expanding their precision drilling setup.
Explore our full range of machine accessories and diamond drill bits to complete your precision drilling setup. For bulk orders or custom configurations, contact our team for tailored solutions.