Ruby Polishing Stones

High-purity synthetic ruby oilstones (Mohs 9 hardness) for hand polishing mold surfaces, slot deburring, and micro-machining tools.

1. Standard Rectangular Stones Flat & General Purpose

General Surface Polishing

Standard Ruby Stone (150×50×25mm)

Standard Dimensions: 150 × 50 × 25 mm / 100 × 20 × 10 mm
Grits Available: 180#, 240#, 400#, 800#, 1200#
Material: Sintered Synthetic Ruby (Aluminum Oxide)
Application: Hand polishing mold cavities, leveling weld beads, and removing fine scratches.

Request Free Sample & Quote →

2. Slim & Narrow Slot Stones Ribs, Slots & Tight Cavities

Narrow Slots & Ribs

Slim Ruby Stone (100×10×10mm)

Standard Dimensions: 100 × 10 × 10 mm / 100 × 6 × 6 mm
Grits Available: 240#, 400#, 800#, 1200#, 3000#
Material: High-density Sintered Ruby
Application: Polishing narrow slots, rib grooves, and small internal holes in injection molds.

Request Free Sample & Quote →

3. Shaped & Profile Stones Round, Triangular & Semi-Circle

Complex Contours & Angles

Profile Ruby Stones (Round / Triangular)

Profiles Available: Round Rod, Triangular, Half-Round, Knife-Edge
Grits Available: 320#, 600#, 1000#, 2000#
Material: High-density Sintered Ruby
Application: Deburring sharp internal angles, radius polishing, and lathe cutter sharpening.

Request Free Sample & Quote →

Ruby Stone Grit & Size Selection Guide

Choose the correct grit size and shape profile based on your workpiece geometry and polishing stage.

Grit Grade	Color / Finish Impact	Stage	Recommended Purpose
180# - 240#	Rough Surface Cut	Heavy Deburring	Remove heavy machining marks, weld excess, EDM scale.
320# - 400#	Medium Matte Finish	General Polishing	Standard mold cavity polishing and edge deburring.
800# - 1200#	Fine Semi-Gloss	Fine Finishing	Eliminate rough stone scratches before diamond paste polishing.
2000# - 3000#	Ultra-Fine Sheen	Pre-Mirror Prep	Micro-finishing on carbide dies and optical mold steel.

Frequently Asked Questions (FAQ)

Q: What are the advantages of ruby polishing stones over standard aluminum oxide stones?

A: Synthetic ruby stones (sintered micro-crystal aluminum oxide) possess extremely high hardness (Mohs 9) and excellent wear resistance. They maintain sharp geometric edges far longer than standard stones, making them superior for narrow slots and precision ribs.

Q: Should ruby stones be used wet or dry?

A: Ruby stones perform best when used wet with a light polishing oil, kerosene, or water-soluble lubricant. Lubrication prevents metal swarf from clogging the stone pores and ensures a smoother surface finish.

Q: What grit sizes are available for ruby mold polishing stones?

A: Common grit sizes range from 180# (coarse deburring) and 240#/400# (general surface grinding) up to 800#/1200#/3000# for pre-mirror polishing.

🎁 Request Free Sample