WORX WX803.9 18V vs Mini Angle Grinder for DEWALT 18V 20V Batteries

Performance and Motor Power

The SWTHM Mini Angle Grinder for DEWALT 18V 20V Batteries delivers significantly higher performance than the WORX WX803.9 18V. With a maximum no-load speed of 20,000 RPM compared to the WORX’s 8,600 RPM, it operates at nearly double the rotational speed, enabling faster cutting and grinding across materials. This advantage is further amplified by its 400W brushless motor, which provides more consistent power output and better efficiency than the WORX’s standard motor. The SWTHM also features an overheat protection system that automatically shuts down at high temperatures and resumes after 30 seconds of cooling, enhancing long-term reliability during intensive use.

Size, Weight and Portability

The SWTHM Mini Angle Grinder is markedly more compact and lightweight than the WORX WX803.9 18V. Weighing just 0.99kg, it is designed for fatigue-free one-handed operation, ideal for extended use in tight or overhead spaces. Its overall dimensions measure 22.7cm × 10.5cm × 9cm, making it easier to carry and manoeuvre during on-site repairs or home renovations. In contrast, the WORX WX803.9 18V lacks explicit weight and dimension data in its listing, but its description highlights “very compact” design, suggesting it prioritises handling ease. However, without measurable specs, the SWTHM’s clear advantages in portability stand out as objectively superior.

Compatibility with Battery Systems

The SWTHM Mini Angle Grinder offers broader compatibility with DEWALT’s ecosystem, supporting multiple 18V and 20V Max lithium batteries including DCB181, DCB182, DCB200, and others. It explicitly excludes only DCB183 and DCBP520 models, providing flexibility for users already invested in DEWALT’s battery platform. The WORX WX803.9 18V uses the Powershare platform, which allows battery interchangeability across WORX’s 20V range of tools, but this creates a separate ecosystem incompatible with DEWALT batteries. For users with existing DEWALT batteries, the SWTHM is the only viable option; those committed to WORX gear will find the WORX tool fully compatible within its own system.

Blade Size and Material Versatility

The SWTHM Mini Angle Grinder uses a 3-inch (7.5cm) saw blade, larger than the WORX WX803.9 18V’s 125mm disc. This size difference translates into greater cutting depth and capacity, particularly useful for thicker metal or tile work. The SWTHM package includes two metal-cutting blades and supports additional blade types for wood, PVC, and tiles, enabling multi-material versatility. The WORX WX803.9 18V specifies a 125mm disc size but does not mention blade type or material compatibility beyond general use. While both tools are suited for metal and general grinding, the SWTHM’s inclusion of dedicated blades and quick-change mechanism gives it a practical edge for diverse DIY and professional tasks.

Safety and Operational Features

The SWTHM Mini Angle Grinder includes advanced safety features not present in the WORX WX803.9 18V listing. It has a dual safety lock and start switch to prevent accidental activation, a protective guard to block sparks, and a digital display showing real-time battery level. These features enhance control and user confidence during operation. Additionally, its LED light illuminates dim work areas, improving visibility and precision. The WORX model lacks any mention of safety mechanisms beyond standard design, and there is no indication of a battery indicator or auxiliary lighting. For users prioritising operational safety and visibility, the SWTHM offers a clearly superior feature set.

Price and Value Comparison

The SWTHM Mini Angle Grinder is priced at £49.99, making it about 39% cheaper than the WORX WX803.9 18V, which costs £81.99. This represents a saving of £32.00, offering significant value for money. The SWTHM’s lower price is matched by a higher performance rating and more advanced features, including brushless motor technology, LED lighting, and digital battery monitoring. While the WORX has a slightly better bestseller rank (5 vs 22), its higher cost and fewer functional advantages make it less competitive on value. For budget-conscious buyers seeking strong performance, the SWTHM delivers far more for less.

Which should you buy?

Choose the SWTHM Mini Angle Grinder for DEWALT 18V 20V Batteries if you need a high-performance, versatile, and affordable tool that leverages your existing DEWALT battery investment. At £49.99, it is 39% cheaper than the WORX WX803.9 18V (£81.99), while offering a 20,000 RPM brushless motor, 3-inch blade compatibility, LED lighting, and built-in safety systems. Its lightweight design and tool-free blade changes enhance usability in tight spaces. Opt for the WORX WX803.9 18V only if you are already committed to the WORX Powershare ecosystem and prefer a slightly smaller 125mm disc for general-purpose grinding—though it lacks key safety and visibility features found in the SWTHM.