Alpha® PSG-658 Pneumatic Stone Grinder (5/8"-11)The Alpha® PSG-658 is a high-performance wet pneumatic stone grinder built from the ground up for stone fabrication — not a retrofitted dry angle grinder. A 5/8"-11 spindle drives polishing pads, Vexcel rigid discs and Spike resin-removal discs at 8,500 RPM, while the center water-feed system delivers ample water through four passage holes in the shower bolt to keep dust down and extend wheel life. At 2.9 lbs (1.3 kg) the PSG-658 is smaller and lighter than most electric angle grinders and ships turn-key with 15 ft (4.5 m) all-weather air and water hoses.Features Designed from scratch as an industrial wet grinding tool for stone — not a retrofitted dry grinder 5/8"-11 spindle drives standard polishing pads, Vexcel rigid discs and Spike resin-removal discs Unique center water-feed system with 4-hole shower bolt cools both faces of the wheel 8,500 RPM no-load speed at just 15 CFM @ 85 PSI — runs on a standard shop compressor Lightweight 2.9 lbs (1.3 kg) and only 7-1/2" (190.5 mm) long for all-day handling Spring-return throttle prevents accidental starts; composite end case keeps the operator's hand warm Silicon gear head cover provides cushion and thermal insulation in cold environments All-weather 15 ft (4.5 m) hoses rated -40°F to +140°F (-40°C to +60°C) One-year tool warranty (see manual for details) .dst-accordion { margin-top: 25px; border: 1px solid #FDDCC5; border-radius: 6px; overflow: hidden; } .dst-accordion-item { border-bottom: 1px solid #FDDCC5; } .dst-accordion-item:last-child { border-bottom: none; } .dst-accordion-toggle { display: none; } .dst-accordion-label { display: flex; justify-content: space-between; align-items: center; padding: 14px 20px; cursor: pointer; font-size: 17px; font-weight: 700; color: #231F20; background: #fff; transition: background 0.2s; } .dst-accordion-label:hover { background: #FFF3EB; } .dst-accordion-label::after { content: '+'; font-size: 22px; font-weight: 700; color: #F15C22; transition: transform 0.3s; } .dst-accordion-toggle:checked + .dst-accordion-label { background: #FFF3EB; } .dst-accordion-toggle:checked + .dst-accordion-label::after { content: '\2212'; } .dst-accordion-content { max-height: 0; overflow: hidden; transition: max-height 0.4s ease; padding: 0 20px; background: #fff; } .dst-accordion-toggle:checked ~ .dst-accordion-content { max-height: 5000px; padding: 15px 20px 20px; } Models / Part Numbers Part No. Thread Disc Size Air Consumption UPC PSG-658 5/8"-11 6" (150 mm) max 15 CFM (425 L/min) 749173430176 How to Use Connect the PSG-658 to a compressor delivering at least 15 CFM at 85 PSI (6 Bar); larger compressors will keep multiple tools running simultaneously. Hook up the water hose to a standard supply using the included quick coupler with shut-off valve; confirm water reaches the shower bolt and exits all four passage holes. Mount the reversible side handle in the position best suited for the application (left or right of the body). Thread the appropriate 5/8"-11 disc or pad onto the spindle and tighten using the included wrench. For grinding, Alpha® recommends 5" Vexcel Rigid Disc 25 grit (heavy grinding) or 35 grit (general shaping); for resin removal use the 5" Spike Disc 35 grit. For profile finishing, switch to a VFlex Flexible Sanding Disc in 35, 50 or 80 grit. For cutting applications, fit a cutting blade with HydroQuad™ Adapter so water is delivered to both sides of the blade. At shift end, add a few drops of AIR-008 rust inhibitor oil at the oil port and slowly introduce air pressure to lubricate the rotor and cylinder. Specifications by Variant 6" Pneumatic Stone Grinder (5/8"-11 spindle) — PSG-658 Part No. PSG-658 UPC 749173430176 Type 6" Pneumatic Stone Grinder (5/8"-11 spindle) Packaged Weight 8.35 lbs Package Dimensions 13.5" x 11.5" x 3.5" Commodity Code 8467.11.5090 Country of Origin Japan Common Specifications Property Detail Spindle 5/8"-11 No-Load Speed 8,500 RPM Air Pressure 85 PSI (6 Bar) Air Consumption 15 CFM (425 L/min) Air Inlet 1/4" BSPP Water Inlet 1/8" BSPP Tool Weight 2.9 lbs (1.3 kg) Tool Length 7-1/2" (190.5 mm) Hose Length 15 ft (4.5 m), water + air; -40°F to +140°F Country of Origin Japan Status Discontinued by manufacturer — spare parts available Warranty One year (see manual) Related & Companion Products Alpha® PSC-150 / PSC-600 Pneumatic Stone Cutter Alpha® Vexcel Rigid Disc 5" (VDR50xx) Alpha® VFlex Flexible Sanding Disc 5" Alpha® Spike Disc Alpha® AIR-008 Rust Inhibitor Oil for Pneumatic Tools FAQs What causes the PSG-658 to bog down even with an adequate compressor?Multiple pieces of equipment sharing the compressed-air line may reduce available airflow. Verify total CFM demand for everything connected to the line and add reserve-tank capacity if needed.How is the PSG-658 different from competing wet grinders?Most wet grinders are dry metal angle grinders retrofitted with external water feeds. The PSG-658 was designed from scratch as a stone-industry wet grinder, with a center water-feed system that cools both faces of the wheel.Can the PSG-658 perform cutting operations?Yes. Alpha® recommends using a cutting blade with the HydroQuad™ Adapter so water is delivered to both sides of the blade.What is the warranty period?One-year tool warranty. See the manual for full details.Can the PSG-658 run dry?Yes, but Alpha® recommends pairing it with an Ecoguard W5 or W6 dust-collection cover and a HEPA vacuum to stay compliant with the OSHA respirable-silica rule.Does Alpha® offer an electric high-speed grinder with center water feed?No. Alpha® offers the WSPKIT to convert popular electric grinders into wet cutting / grinding / profiling tools instead.How much rust inhibitor oil should I add?Only a few drops at shift end. Slowly introduce air pressure to lubricate the rotor and cylinder. Full air pressure will simply expel the oil through the exhaust.Which discs does Alpha® recommend for grinding?5" Vexcel Rigid Disc 25 grit (VDR5025) for heavy grinding, 35 grit (VDR5035) for general shaping, and the 5" Spike Disc 35 grit (VCS5035) for resin/net removal.Are flexible discs available for profile finishing?Yes. The 5" VFlex Flexible Sanding Disc (VDF50xx series) ships in 35, 50 or 80 grit for round-over edges and vanity rim cleanup. VideosNo product-specific videos are currently available from the manufacturer or DST. Documentation 📄 PSG-658 Manual (v0620) 📄 PSG-658 Parts & Schematic (v0122) 📄 PSG-658 Flyer ⚠ WARNING: Cancer and Reproductive Harm — www.P65Warnings.ca.gov. Always wear appropriate PPE.
