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Alpha Groove Cutters for Granite & Engineered Stone
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At a Glance
Quick Decision Guide
Blade Thickness
4.2mm
Recommended Slab
3/4"
Thread
5/8"-11
Maximum RPM
14,500
Material
Granite
Application
Joint Seaming
Cutting Method
Wet
Tool Type
High-Speed Angle Grinder
Why Choose This Product
Key Benefits
Level Groove Alignment
Produces consistent mating grooves for countertop seams
Slab-Specific Sizes
Matches 4.2mm cutters to 3/4" slabs and 7.5mm cutters to 1-1/4" slabs
Joint Seam Preparation
Creates grooves for accurately aligned butt joints
Material Compatibility
Designed for granite and engineered stone fabrication
High-Speed Grinder Use
Rated up to 14,500 RPM on compatible 5" angle grinders
Two Thread Options
Available with 5/8"-11 or M14-2 connections
Product Information
Product Details
Specifications
Brand
Alpha®
Part Number
GCW258
UPC
749173470516
Product Type
Wet Groove Cutting Blade
Blade Thickness
4.2mm
Recommended Slab Thickness
3/4"
Thread
5/8"-11
Maximum RPM
14,500
Recommended Material
Granite
Additional Material
Engineered Stone
Application
Joint Seaming
Cutting Method
Wet
Tool Compatibility
High-Speed Angle Grinders
Groove Performance
Creates level, consistent grooves for joint seams
About This Product
Wet Groove Cutters for Countertop Joint Seaming
Alpha® Groove Cutters are wet-use blades designed to create level, consistent grooves for butt-joint seaming in granite and engineered stone. Their specialized design keeps mating grooves aligned, supporting strong and accurately positioned countertop seams.
4.2mm and 7.5mm Groove Cutting Options
The 4.2mm Groove Cutters are recommended for 3/4" (2cm) slabs, while the 7.5mm models are designed for 1-1/4" (3cm) slabs. Both thicknesses are available with either a 5/8"-11 or M14-2 thread, allowing the groove cutter to be matched to the slab and compatible grinder.
5" High-Speed Angle Grinder Compatibility
All four models have a maximum operating speed of 14,500 RPM and are designed for compatible 5" high-speed angle grinders. Alpha specifies using the Groove Cutter with its Universal Safety Guard Kit, an external water supply, and a Ground Fault Circuit Interrupter for wet groove cutting.
Product Resources
Documentation & Downloads
Common Questions
Frequently Asked Questions
What are Alpha Groove Cutters used for?
They create level, consistent grooves for butt-joint seaming in granite and engineered stone countertop slabs.
Which Alpha Groove Cutter should I use for a 3/4" slab?
Use a 4.2mm Groove Cutter for 3/4" (2cm) slabs. GCW258 uses a 5/8"-11 thread, while GCW214 uses an M14-2 thread.
Which Alpha Groove Cutter should I use for a 1-1/4" slab?
Use a 7.5mm Groove Cutter for 1-1/4" (3cm) slabs. GCW358 uses a 5/8"-11 thread, while GCW314 uses an M14-2 thread.
What materials can Alpha Groove Cutters be used on?
Alpha specifies the granite Groove Cutters for joint seaming granite and engineered stone.
What is the maximum operating speed?
All four Groove Cutter models have a maximum operating speed of 14,500 RPM. Do not exceed the cutter's rated maximum speed.
What thread sizes are available?
The Groove Cutters are available with 5/8"-11 and M14-2 threads. Select the configuration that matches the compatible angle grinder.
Are Alpha Groove Cutters used wet or dry?
They are designed for wet use only. Alpha specifies an appropriate Universal Safety Guard Kit with water feed, an external water supply, and a Ground Fault Circuit Interrupter.
Can an Alpha Groove Cutter be used with a router or polisher?
No. It is not a groove router bit, and Alpha does not approve it for use on a polisher. The Groove Cutter must be used with a compatible 5" high-speed angle grinder and the required wet-cutting safety equipment.