Starrett 649-1 Spindle Square Range Graduation Milling Machine Tramming Tool - 0.250 0.001

The Starrett 649-1 Spindle Square is a patented precision instrument designed to make tramming the head of a vertical milling machine fast, accurate, and repeatable. Ensuring squareness and perpendicularity between the spindle and the work surface is a critical, routine maintenance task — and the 649-1 makes it significantly easier and more precise than traditional methods using a single dial test indicator.

Key Features:

• Measuring Range: 0 to 0.250" (6.35mm)
• Graduation: 0.001" (0.0254mm) with 0-50-0 dial reading
• Dual Indicators: Fully assembled with two AGD Group 2 dial indicators for simultaneous readings
• Shank Diameter: 3/8" — fits standard milling machine collets
• Contact Point Spread: 4" (100mm) between contact points
• Overall Size: Approximately 6-3/4" (172mm) wide and 5-1/2" (140mm) from top of shank to contact point tips
• Construction: Solid steel body with durable black oxide finish
• Ground Gaging Surface for accuracy and repeatability
• Patented Design — proven in machine shops worldwide
• Made in the USA

Includes: Custom fitted carrying case

How It Works: Zero both indicators on a surface plate, then insert the 649-1 into the milling machine collet and lower the head until each indicator needle has rotated approximately one full revolution. When both indicators display identical numerical readings, the spindle is square to the table — regardless of needle position.

The Starrett 649-1 is the go-to spindle square for machinists, toolmakers, and shop maintenance professionals who demand reliable, repeatable results when setting up vertical mills.