How to Choose a Cordless Grinder - a Toolstop Buying Guide

The world of professional power tools is relentless moving towards cordless power. The ability to work independent from a constant power source is hugely appealing, meaning you aren't tethered to cables or power cords, and can access tricky to reach work areas much more easily.

As the battery technology behind these cordless tools continues to evolve and improve, power tool manufacturers and pushing the boundaries, slotting batteries onto power tools that were once absolutely tethered to a mains output.

Grinders have been fitted with batteries for a while, but:

• what should you look out for when choosing a cordless grinder?
• will a cordless grinder match up the applications I want to undertake?
  
• how can you make sure you'll get the best cordless grinder for your typically applications?
• which one will give you the right balance of power and performance per battery charge?

We've put together a shortlist of cordless grinders and whittled down all of the manufacturers' bluff about their features so that, at a glance, you'll have a rough idea of the performance and features of the top cordless grinders on our website.

Look out for the maximum size of grinding disk that you can fit, the top speed that it'll spin the disks, any special features related to protecting you - and the tool - from misuse, and the sort of batteries the grinder is compatible with.

While cordless grinders have perhaps been viewed as tools that you only use if you've got a very quick job to undertake, such as a couple of cuts, or to quickly deburr some material, nowadays you can expect them to perform like corded grinders. Up to a point...

The power rating on your cordless battery is vitally important.

The Makita, Bosch and Metabo offerings all support (or are supplied with) 3Ah 18v batteries. This means you'll get longer run time and high power from your grinder. The DeWalt is supplied with a NiMH battery, but it's still 18v, while offering a slightly lower power rating of 2.6Ah.

Using a grinder carries some level of risk.

You're operating a machine that will be spinning an abrasive disk or cutter at extemely high speeds. You need your cordless grinder to be in asbolute control over the electronics of the motor. The electronics should be constantly monitor the motor - and the battery - to makes sure you, the operator, are not putting undue stress on either.

Working the grinder too hard could result in the disk shattering, the motor jamming or other such mechanical failures.

With this in mind, your ginder should be equipped with some sort of diagnostic system, whether it's as simple as a fan that keeps the motor cool while you work, or a more sophisticated system such as electronic limiters, electronic motor protection or themal overload cut out, each of which are intended to keep you - and your investment - safe will you grind or cut.

Flexibility with the size of disk you can fit onto the cordless grinder may be something to consider. Both the Metabo and the DeWalt grinders can take disks up to 125mm in size, but they do lack some of the speed offered by both the Makita and Bosch models, which take 115mm disks.

Metabo offer a 3 year warranty on the grinder and the supplied 3Ah 18v lithium-ion batteries, while Bosch supplies its in an L-Boxx. The DeWalt and Makita grinders are supplied in kit bags.

In summary, then a cordless grinder may be the answer if you need to be independent from a power source while you work, but recognise that a cordless grinder won't give you the same amount of power or run times than a corded equivalent.

Safety must come first, so check to make sure your new cordless grinder has enough safety checks and balances on the motor and battery, and pay close attention to the power rating of the battery and the motor.

If you've got any questions about cordless grinder and the range we stock, let us know in the comments or on Facebook.

See the cordless grinders in action:
Bosch GWS 18V Li
Metabo W18 LTX

DeWalt DC411