Five Inch Fully Machined Threaded Back Plate For Lathe Chuck With 1.5 Inch By 8 T Thread, Shoulder Diameter 3.78 Inches, Bolt Circle 4.25 Inches, Flange Thickness 0.708 Inches, Fits Three Or Four Jaw Chucks SKU 2026192

Single Five Inch Machined Lathe Chuck Back Plate for 1-1/2 x 8 T
✔️ 1-1/2'' x 8T thread, shoulder 3.78'', bolt circle 4.25'', flange 0.708''

This five inch back plate is a precision machined mounting adapter designed to fit lathe chucks that use a 1-1/2 inch by 8 T thread. It’s meant for install with three- or four-jaw chucks, and requires machining to create a precise seating surface on your chuck body.

✅ Thread size: 1-1/2'' x 8T
✅ Shoulder diameter D1: 3.78"
✅ Bolt circle diameter D2: 4.25"
✅ Flange thickness B: 0.708"
✅ Fits three- or four-jaw lathe chucks

💡 What is a lathe chuck back plate used for in workshop setups?

Handy workshop component that lets you mount a chuck to a lathe spindle with a precise thread and seating surface.

- Supports quick chuck swaps with compatible back plates - Improves alignment and reduces runout in turning operations - Useful when upgrading to a different chuck style