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5/8-11 Threaded Hubs for Cut-Off Wheels, Grinding Wheels and Flap Discs

A 5/8-11 threaded hub is a common mounting option for abrasive products used on compatible U.S.-market angle grinders.

The abrasive wheel has a 5/8-11 UNC internal thread that screws directly onto a grinder with a matching 5/8-11 external spindle. This provides convenient installation without the standard retaining-nut arrangement used with many plain arbor-hole discs.

Many professional angle grinders sold in the United States use a 5/8-11 UNC spindle. However, the grinder specification should always be checked before selecting an abrasive product.

What Does 5/8-11 Mean?

The designation 5/8-11 describes the thread size:

• 5/8 inch: nominal thread diameter
• 11: threads per inch
• UNC: Unified National Coarse thread

The recommended product description is:

5/8-11 UNC Threaded Hub

Do not describe it simply as a “5/8-11 hole.” A plain opening is an arbor hole, while 5/8-11 is a threaded mounting system.

5/8-11 Cut-Off Wheels

A 5/8-11 cut-off wheel has an integral threaded hub for direct mounting on a compatible angle grinder spindle.

These products may include Type 1 or depressed-center Type 27 cut-off wheels, depending on the wheel design. Typical applications include:

• Cutting steel and stainless steel
• Cutting sheet metal
• Cutting stainless steel tubing
• Cutting exhaust pipes and clamps
• Notching and fabrication work

Major U.S. abrasive ranges include Type 1 and Type 27 cut-off wheels with optional 5/8-11 hubs. Only use a wheel for grinding when it is specifically designed and marked as a combined cut-and-grind wheel.

5/8-11 Grinding Wheels

A 5/8-11 grinding wheel is normally a reinforced, depressed-center wheel designed for material removal with an angle grinder.

Typical applications include:

• Weld removal
• Heavy stock removal
• Edge grinding
• Beveling
• Deburring
• Surface preparation

Common U.S. sizes include 4-1/2, 5, 6, 7 and 9 inches. Type 27 grinding wheels with 5/8-11 internal threads are widely available for steel and stainless-steel fabrication.

5/8-11 Flap Discs

A 5/8-11 flap disc has an integral threaded hub that mounts directly onto a compatible grinder spindle.

Flap discs are commonly used for:

• Weld grinding and blending
• Edge deburring
• Beveling
• Surface preparation
• Rust and coating removal
• Finishing steel and stainless steel

Available constructions can include:

• Type 27 flat flap discs
• Type 29 conical flap discs
• Curved flap discs for fillet welds
• Zirconia alumina flap discs
• Ceramic abrasive flap discs

Abrasive manufacturers specifically describe 5/8-11 internal-thread flap discs as products designed for direct mounting on tools with matching 5/8-11 external threaded shafts.

5/8-11 Threaded Hub vs. 7/8-Inch Arbor Hole

These mounting systems should not be treated as interchangeable without approved mounting hardware.

How to Check Compatibility

Before installing a 5/8-11 abrasive wheel, confirm:

1. The grinder has a 5/8-11 UNC spindle.
2. The wheel diameter is approved for the grinder.
3. The wheel’s maximum RPM is equal to or higher than the grinder speed.
4. The product is designed for the intended cutting, grinding or finishing operation.
5. The correct grinder guard is installed.
6. The threaded hub is clean, undamaged and properly seated.

Never force a 5/8-11 threaded product onto an M14 or other incompatible spindle.

RECORE 5/8-11 Product Options

RECORE can supply 5/8-11 threaded-hub products for the U.S. market, including:

• Ultra-thin cut-off wheels
• Type 27 grinding wheels
• Standard flap discs
• Curved flap discs
• Zirconia alumina products
• Ceramic abrasive products

Available specifications can be customized according to wheel diameter, thickness, abrasive grain, grit, target material, maximum operating speed, label and packaging requirements.

Frequently Asked Questions

Is 5/8-11 the same as a 5/8-inch arbor hole?

No. A 5/8-inch arbor hole is a plain opening. A 5/8-11 threaded hub has an internal thread with 11 threads per inch.

Is 5/8-11 the same as M14?

No. They use different thread dimensions and pitches and should not be forced together.

Does a 5/8-11 disc require a retaining nut?

An abrasive product with an integral 5/8-11 threaded hub normally mounts through the hub itself. Always follow the instructions for the exact grinder and abrasive product.

Can a 5/8-11 cut-off wheel also be used for grinding?

Only when the wheel is specifically designed, tested and marked for both cutting and grinding. Standard thin cut-off wheels should not be used for side grinding.

Which information is required for an enquiry?

Please provide:

• Product type
• Wheel diameter and thickness
• 5/8-11 threaded-hub requirement
• Abrasive grain and grit
• Workpiece material
• Grinder speed
• Application
• Packaging requirements

Request a 5/8-11 Abrasive Product

RECORE provides standard and custom 5/8-11 cut-off wheels, grinding wheels and flap discs for compatible U.S.-market angle grinders.

Contact us with your product size, machine speed, target material and application requirements for product selection or OEM development.