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How to Choose a Cordless Grinder – a Toolstop Buying Guide

Posted by Toolstop Fraser on 25th Jan 2017

The world of professional power tools is relentlessly moving towards cordless power. The ability to work independently 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 you want to undertake?
  • how can you make sure you’ll get the best cordless grinder for your typical 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 (click here to go straight to our short list) 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. If we’ve got a demo of the grinder in action, you’ll be able to see it on Toolstop TV.

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 capacity of the battery you’ll be using in your cordless grinder is important. Clearly, the motor in the grinder is going to need to draw lots of juice from the battery pack, so the higher the capacity of the battery is important.

And now that we’ve seen Dewalt launch 54v cordless tools, including a grinder (click to read our review), we can expect the other manufacturers to follow suit with higher power cordless grinders that are truly capable of replacing corded versions.

Obviously, if you’ve got a few 18v Li-ion batteries kicking about, buying a naked (or body only) grinder might be more cost effective as you’ll be able to slap in a battery, while your others are charging.

Using a grinder carries some level of risk.

You’re operating a machine that will be spinning an abrasive disk or cutter at extremely high speeds. You need your cordless grinder to be in absolute control over the electronics of the motor. The electronics should 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 disc shattering, the motor jamming or other such mechanical failures.

With this in mind, your grinder 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 thermal overload cut out, each of which is intended to keep you – and your investment – safe will you grind or cut.

Our recomendations for best cordless angle grinder:

Makita DGA452Z Cordless Li-ion Angle Grinder 18V (Body Only) – SHOP HERE

Key Spec:
  • No Load speed: 10,00 rpm
  • Disc size: 115mm
  • Easy-to-grip, small circumference motor housing
  • Compatible with Makita’s 18v 3Ah, 4Ah  & 5Ah batteries
  • Weight: 1.9kg
Benefits:
  • More compact design at only 12-1/2″ long and weighs only 5.6 lbs. for less operator fatigue
  • Equipped with Battery protection circuit
  • Anti-restart function
  • Electronic current limiter

Bosch GWS18-125V-LI 18V Li-ion Cordless Angle Grinder 125mm in L-Boxx (2 x 4Ah Batteries)

Key Specs:
  • No Load speed: 10,000rpm
  • Cutting depth: 35mm
  • Disc size: 125mm
  • Spindle: M14
  • Weight: 2.4kg
Benefits:
  • Very powerful due to high performance 4 brush motor with “lifetime brush”
  • Long life due to overload protection (ECP & EMP)
  • Ergonomic with slim grip and short length and only 2.4 kg
  • Safe to use due to bullet proof guard, two-motion side switch and restart protection
  • Compact size makes it easy to use in narrow spaces
  • Light weight and well-balanced for easy one-hand usage
  • Slim and comfortable grip size and soft-grip

Dewalt DCG414T2 Grinder XR Flexvolt 54V Cordless 125mm (2 x 6.0Ah Batteries) – SHOP HERE

Key Specs:
  • Disc size: 125mm
  • No load speed: 7,000rpm
  • Spindle: M14
  • Supplied with 2x 54v XR FlexVolt batteries, charger and 2 position side handle
  • Weight: 2.2kg
Benefits:
  • Powered by a 54v brushless motor
  • Electronic brake
  • Electronic clutch
  • Includes a keyless protective guard
  • Ergonomic grip, rubber over moulding and hand/arm vibration when grinding of 5.9 m/s²

Hitachi G 18DBAL Angle Grinder 18V Cordless Brushless – SHOP HERE

Key Specs:
  • Disc Diameter: 115mm
  • No load speed: 9000rpm
  • Weight: 2.4kg
  • BODY-ONLY, compatible with Hitachi’s 18v batteries
Benefits:
  • Brushless motor
  • Smallest body & grip circumference, most lightweight in its class
  • Dust and water-resistant construction that remarkably increases durability
  • Electronic control – Kickback protection system, anti-restart protection and soft start

Metabo W18LTX Angle Grinder 115mm Quick Cordless (Body Only) in Metaloc Box – SHOP HERE

Key Specs:
  • Disc size: 115mm or 125mm
  • No load speed: 8,000rpm
    Spindle thread: M 14
  • Quick adjusting nut
  • Supplied body-only in a Metaloc box
  • Weight: 2.4kg
Benefits:
  • Metabo claim this cordless grinder will behave – and give you the same capabilities – as a corded grinder
  • Robust and wear-resistant motor featuring easy-access carbon brushes
  • Motor protection via thermal overload cut out and overload cut out features
  • Detachable dust filter
  • The battery pack can be rotated to allow you access to tight spaces


In summary, then a cordless grinder may be the answer if you need to be independent of 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!