Astro Tool
Astro Tools 30045 ONYX 4.5" Compact Air Angle Grinder - 0.8HP
Disclosure: We may earn a commission when you buy through links on this page, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Learn more
Highlights
- For popular 4.5” grinding disc size with 7/8” arbor hole (5/8"-11 thread size)
- Compact overall size for a 4.5” grinder at just 8.5” long
- Push button spindle lock
- 0.8 horsepower, 12,000 rpm
Why You'll Love It
- Operates standard 4.5-inch discs with a common 7/8-inch arbor hole
- Short 8.5-inch overall length makes handling easier in tight work areas
- Generates 0.8 horsepower and runs up to 12,000 rpm for grinding tasks
- Push-button spindle lock simplifies and speeds up wheel changeouts
Pros
- +Compact 8.5-inch body length
- +Standard 5/8-11 thread size
- +Built-in push-button spindle lock
- +Reaches up to 12,000 rpm
Cons
- -Requires a dedicated air supply setup
- -Listing does not state air consumption specs
Detailed Review
The Astro Tools 30045 ONYX is a pneumatic angle grinder designed to run standard 4.5-inch discs while maintaining a small working profile. It fits workshops and job sites that already utilize compressed air and need a dedicated tool for grinding, shaping, or cutting metal.
Equipped with a 0.8-horsepower motor spinning up to 12,000 rpm, this pneumatic tool delivers steady rotational speed. It uses standard 4.5-inch grinding discs with a 7/8-inch arbor hole and a 5/8-11 thread size, keeping replacement accessories widely accessible. A built-in push-button spindle lock allows you to hold the spindle steady when changing out worn wheels.
Measuring 8.5 inches in total length, the tool offers a more compact form factor than many conventional pneumatic grinders. However, operating it requires a continuous compressed air supply, and the product data does not list the specific CFM requirements, operating air pressure, or included accessories.
Verdict: The Astro Tools 30045 ONYX is well suited for technicians and metalworkers seeking a compact, 0.8-horsepower pneumatic grinder that uses standard 4.5-inch wheels. If you have an air system ready to go and want an 8.5-inch tool with a push-button spindle lock, it is a practical choice.
Specifications
- Disc Size: 4.5 inches
- Arbor Hole Size: 7/8 inch
- Thread Size: 5/8-11
- Overall Length: 8.5 inches
- Motor Power: 0.8 HP
- Free Speed: 12,000 RPM
- Spindle Mechanism: Push button spindle lock
Who Should Buy It
A great fit if you:
- Work with standard 4.5-inch discs featuring a 7/8-inch arbor or 5/8-11 thread.
- Need a shorter 8.5-inch pneumatic tool body to fit smaller spaces.
- Prefer the quick wheel swaps of a push-button spindle lock mechanism.
Consider something else if you:
- Do not have an air compressor setup available in your workspace.
- Need to verify specific CFM air volume requirements before purchasing.
FAQ
What size grinding discs does this tool take?
It fits standard 4.5-inch grinding discs that have a 7/8-inch arbor hole and use a 5/8-11 thread size.
How fast does this air grinder spin?
The 0.8-horsepower motor delivers an operating speed of up to 12,000 rpm.
How long is the tool body?
The overall length of the grinder is 8.5 inches.
Product Details
| Brand | Astro Tool |
| ASIN | B01JBIJADY |
