17pc R8 ER-40 Collet Chuck Set 1/16″-5/8″ Range | Bridgeport Mill | MPN 3900-0005

17-Piece R8 Taper ER-40 Collet Chuck Set (MPN: 3900-0005)

This listing is for a complete, high-precision 17-piece R8 ER-40 Collet Chuck Set. This is the single most valuable upgrade for any R8 spindle machine, including Bridgeport-style mills, mill-drills, and many other vertical milling machines.

The ER-40 collet system offers a massive gripping range and superior concentricity, allowing you to securely hold any tool from 1/16″ to 5/8″ in diameter.

Technical Specifications & Key Features

• High Precision: The chuck (holder) is balanced and certified to 0.0005″ T.I.R. (Total Indicated Runout), ensuring your tools run true for accurate cutting and drilling.

• Taper: R8 Spindle Taper, the North American standard for Bridgeport-style mills.

• Drawbar Thread: Standard 7/16″ – 20 (fits all standard R8 drawbars).

• Construction: The collet chuck is fully hardened and precision ground for maximum durability and accuracy.

• Range: The 15 collets cover a full gripping range from 1/16″ to 5/8″.

What’s Included in the 17-Piece Set?

This kit includes everything you need to get started, all protected in a custom-molded case.

1. (1) R8 ER-40 Collet Chuck (Hardened, Ground, 0.0005″ TIR)

2. (15) ER-40 Spring Collets (Covering the full 1/16″ to 5/8″ range)

   • 1/16″

   • 3/32″

   • 1/8″

   • 3/16″

   • 7/32″

   • 1/4″

   • 5/16″

   • 11/32″

   • 3/8″

   • 13/32″

   • 7/16″

   • 1/2″

   • 17/32″

   • 9/16″

   • 5/8″

3. (1) ER-40 Spanner Wrench (For tightening the collet nut)

4. (1) Fitted Storage/Carrying Case

Why Choose an ER-40 Set?

• Versatility: Each ER collet has a collapsing range of ~1mm (0.039″), meaning it can hold undersized tools or drill bits securely.

• Gripping Power: The 8° collet angle provides exceptional holding force, preventing tool pull-out during heavy cuts.

• Cost-Effective: This single set replaces dozens of individual R8 collets.