Mitutoyo 901991 Roller Contact Point Agd Dial Indicator

Product Description

The MITUTOYO 901991 is a roller-style drop indicator contact point designed for use with AGD dial indicators. Constructed from stainless steel, this replacement contact point features a 4-48 thread for secure mounting and delivers a 0.3937 inch diameter roller with a contact point length of 0.5906 inches (15.00 mm). It is intended for metrology and precision measurement applications where consistent surface contact and repeatable readings are critical. Dial indicator contact points are typically installed and serviced by calibration technicians, machinists, and quality control professionals working in manufacturing, tooling, and inspection environments.

This contact point is suitable for use with AGD Group 1, 2, 3, and 4 dial indicators. The roller style is particularly well suited for measurement applications involving moving workpieces, scribed lines, or surfaces where a flat or spherical point would drag or produce inconsistent contact. It is commonly installed in surface plate setups, comparator stands, and fixture-mounted gaging configurations found in machine shops and quality labs.

Key Features

• Roller contact style reduces drag on moving or delicate surfaces
• Stainless steel construction for corrosion resistance and durability
• 4-48 thread fits standard AGD dial indicator stems
• 0.3937 inch (10.00 mm) roller diameter for stable surface contact
• 0.5906 inch (15.00 mm) contact point length
• Compatible with AGD 1, 2, 3, and 4 indicator groups

Compatibility

Designed for use with AGD Group 1, 2, 3, and 4 dial indicators equipped with a standard 4-48 threaded contact point stem.

Installation Notes

Installation is performed by hand-threading the contact point onto the dial indicator spindle using the 4-48 thread; no power shutoff is required, but the indicator should be removed from service before changing contact points to avoid measurement errors or damage. Use appropriate thread engagement and avoid overtightening, which can distort the spindle or contact point threads. Verify zero calibration after swapping contact points per your facility measurement standard or applicable metrology procedure.