Granite Surface Plate 15.7 x 15.7 x 2.36 in - Grade A Precision

In this review the HHIP 15.7 x 15.7 x 2.36 in Grade A granite surface plate is evaluated for small shops and inspection benches that need a stable, low-maintenance reference surface. The bottom line: this plate is best for machinists, inspectors, and hobbyists who want a hard, non-magnetic, non-conductive work surface with a certified flatness of +/-.0001 in for routine layout, squareness checks, and height gage work. It offers measurable precision without the premium cost of larger, NIST-traceable systems.

Key Features

• Precision ground top: The surface is precision ground to deliver a high degree of flatness so measurements and layouts remain consistent.
• Grade A accuracy: As a Grade A (Grade 0) plate with +/-.0001 in accuracy, it supports fine dimensional checks and calibration tasks in a small shop environment.
• Certificate of inspection: The included certificate documents the plate's flatness verification, providing confidence for inspection and setup use.
• Durable granite construction: Being non-magnetic, non-conductive and harder than steel, the plate resists nicks and burrs and serves as a long-lasting work surface.
• Versatile use: It is suited for measuring flatness and squareness, laying out parts, calibrating instruments, setting up tools, and use with a height gage.
• Quality assurance: HHIP checks plates with an auto collimator for overall accuracy assurance so buyers get a verified flat surface.

Who It's For

The plate is ideal for small machine shops, toolrooms, and inspection benches where a compact, accurate reference surface is needed for layout, gaging and setup. Its 15.7 x 15.7 in footprint gives enough area for most height gage and small fixture tasks without occupying excessive bench space.

Professionals who require NIST-traceable certification or very large working areas should look elsewhere; likewise, users needing a highly polished mirror finish for optical work may prefer a different grade or finish. For routine dimensional work, this plate is a practical, cost-effective choice.

Pros & Cons

Pros

• High documented flatness of +/-.0001 in gives reliable reference accuracy for inspection tasks.
• Non-magnetic, non-conductive granite resists nicks and remains stable over time compared with softer materials.
• Includes a certificate of inspection and is checked by auto collimator for quality assurance.
• Compact size and substantial weight make it a solid, vibration-resistant work surface for small shops.

Cons

• Certificate is not NIST traceable, so it is not suitable where formal traceability is required.
• Surface finish and perceived flatness received mixed feedback from some users, so expectations about polish may vary.

Specifications

Brand	HHIP
Model size	15.7 x 15.7 x 2.36 in
Grade	Grade A (Grade 0)
Accuracy	+/-.0001 in
Material	Granite (non-magnetic, non-conductive)
Certification	Certificate of inspection (not NIST traceable)

Our Verdict

The HHIP Grade A 15.7 x 15.7 x 2.36 in granite surface plate is a sensible, value-focused choice for small shops and inspectors who need a durable, accurate reference surface without NIST traceability. It balances precision, durability, and footprint well, making it a practical tool for layout, gaging and assembly tasks where documented flatness and a stable work plane matter.

Frequently Asked Questions

Is the plate NIST traceable?
No, the included certificate of inspection is not NIST traceable; it documents measured flatness but does not provide NIST traceability.

Can this plate be used with a height gage?
Yes, the 15.7 x 15.7 in top and Grade A accuracy make it suitable for height gage work and routine dimensional checks.

Will the surface nick or magnetize?
No, granite is non-magnetic and harder than steel so it resists nicks and burrs and will not magnetize.