Bad Dog 4.5″ HDII – The Original. The Workhorse. The One That Does It All.
Cut, sand, grind, sharpen, or shape—if the job involves an angle grinder, the 4.5" HDII is built to handle it. Our most popular wheel, the original Bad Dog HDII delivers unmatched versatility, durability, and safety in one rugged tool.
This isn’t your average grinding wheel. The HDII features a solid steel core that won’t shatter or explode like fiberglass wheels if it binds under pressure. Coated with 6 karats of 46 grit industrial-grade diamond on both the face and edge, it gives you incredible wear resistance, fast material removal, and precision across a wide range of applications.
Whether you’re working in metal, masonry, tile, plastic, or composites, the HDII eliminates the need to switch wheels. It cuts like a blade, grinds like a cup wheel, and lasts longer than anything else in your toolbox.
From cutting bolts and grinding welds to shaping stone and sharpening mower blades, the 4.5" HDII does it all—and it does it safely, quickly, and cleanly.
✅ Multipurpose Functionality – Cut, grind, sand, sharpen, and shape—all with one wheel
✅ 6 Karats of Diamond Grit – 46 grit industrial diamond for long life and serious bite
✅ Steel Core = Safety – Won’t explode like fiberglass wheels
✅ Works on Nearly Any Material – Metal, masonry, porcelain, PVC, composites, and more
✅ Edge + Face Coating – Get full cutting and grinding versatility
✅ 7/8″ Arbor – Fits most standard 4.5" angle grinders
✅ Lifetime Guarantee – If it wears out or fails, we replace it—no questions asked
Note: Use with a 4.5" angle grinder. Power tool not included.
Absolutely. The industry standard for grinders is as follows: Rotary Tools (i.e. Dremel TM) - 1/8" 3" Cut off tools and Die Grinder - 1/4" & 3/8” 4" Angle Grinder - 5/8" 4-1/2", 5”, 6", 7" Angle Grinder - 7/8" arbor flange for a 5/8" coarse arbor shaft At Bad Dog, we find that an HDII with a 7/8" arbor flange runs truest because it is a more precise fit. The 4-1/2" and 6" Flange wheel use the 5/8" Coarse thread which is standard on ALL grinders. Call us at 800.252.1330 if you have any questions.
Wood: It will shape wood well but burns when cutting. Glass: The HDII is too aggressive and leaves a jagged edge.
Nothing lasts forever but we Guarantee the HDII for LIFE! If you ever dull or damage your HDII return it to us and we will repair or replace it. For full details see our Lifetime Guarantee page.
We'll replace it - even if it's your fault! Here's a link to the details of our Lifetime Guarantee.
Sometimes when cutting softer metals like aluminum the HDII will "gum" up. If this happens to you, simply run your HDII through a concrete block and it will be as good as new.
As safe as they get! Cut-off wheels can be some of the most dangerous tools in a shop. We are not telling you that you don’t need to be wearing safety when using our wheel, however, the 46 diamond grit is embedded on a hard steel plate to ensure that the wheel will not fly apart on you.
Dull or damage our tools and we will repair or replace them.
Economical Flat Rate Shipping for orders under $50 in the USA. Some exclusions apply.
Don’t love your Bad Dog Tools? Return them in 60 days for your money back.
