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What is the difference between a 4 1/2” Angle Grinder & 5” Angle Grinder?

20 April 2018

Author: Nick Mole 

Our Metal Fabrication Supplies 5” Angle Grinder & Cutting Disc Combination promises to save you time, increase production and make your operator safer.

What are 4 1/2” Angle Grinders used for?

The most common small angle grinder purchased in the UK is the 4 1/2” Angle Grinder. 4 1/2” Angle Grinders are suitable for light duty tasks, or when access could be a problem. Due to the smaller size a 4 1/2” Angle Grinder will never be as productive as a 5” Angle Grinder. 4 1/2” Angle Grinders are also more compact which makes them easier to grip and manoeuvre for some applications. 4 1/2” grinders are purchased more often because they appear to have a lower initial cost when compared to a 5” Angle Grinder. However, when it comes to cost against performance, the 4 1/2” Angle Grinder may not prove to be the best value product when compared against the 5” Angle Grinder. 

Below is a specification comparison between a Metabo 4 1/2” Angle Grinder and Metabo 5” Angle Grinder. The only benefit that the 4 1/2” Angle Grinder seems to offer is its light weight.


4 1/2” Angle Grinder

5” Angle Grinder


Grinding Wheel ø



8.6% greater depth of cut

Rated Input Power



39% more input

Output Power



41% more output

No-load Speed



4.7% faster

Revolutions at Rated Load



6.6% faster




36% greater




12.7% heavier


In a comparison test, we used a Metabo 4 1/2”” Angle Grinder against a Metabo 5” Angle Grinder with the same bond Speedgrit 1.6mm cutting discs. We carried out two cutting comparisons on 8mm x 150mm carbon steel plate. We recorded the number of cuts and average time taken per cut to establish what would be the difference in performance.


4 1/2” Angle Grinder

5” Angle Grinder


In house cutting test results cutting 150mm x 8mm mild steel flat and 1.6mm discs

3 cuts

6 cuts

100% greater consumable life

Average time per cut


55 secs

21.8% faster cutting speed

Time saved = 17.91%

Increased production = 21.81%


The number of cuts achieved with the 5” Angle Grinder were 100% greater than the 4 1/2” Angle Grinder. The 41% output power and 36% torque provided by the 5” Angle grinder, meant that the disc speed remained at its optimum, allowing the disc to work more efficiently. The number of cuts were doubled from only an 8.6% increase disc diameter. 

The extra output power and torque provided by the 5” Angle Grinder ensures the optimum periphery speed of the disc is maintained, this helped to reduce the average time taken per cut by 17.91%.

How much money would I save using a 5” Angle Grinder?

The average UK labour rate for a Fabricator is £10.25 per hour. This means the 5” Angle Grinders could save a possible £1.83 per every hour used. Maintaining the optimum cutting speed also helped to achieve a 21.81% increase in product (based on an average charge out rate of £25 per hour), the 5” Angle Grinders would deliver an extra £5.45 profit per every hour used.

In most industrial applications the larger and more powerful 5” Angle Grinders will quickly give a return on the extra investment made when purchasing. They could save you money, help you make money and in the case of our Metabo grinders and Speedgrit discs, they are designed to be much safer.

Will all 5” Angle Grinders and disc combinations give the same performance and safety?

To deliver a high performance, Metabo angle grinders are fitted with several features.

  • New patent-pending Marathan Motors which deliver up to 50% more torque, 20% more output power and 20% more overload protection compared to most other brands.
  • The S-Automatic Torque Limiting Clutch ensures no kickback arises should a disc jam or snag unexpectedly. This allows for immediate continuation of work afterwards.
  • Auto-Balance ensures up to 50% less hand-arm vibration in surface grinding and stock removal applications. This allows for longer trigger times without the need for further action, it also contributes to doubling the working life when used with grinding discs.
  • Side handle Vibratech handle vibration damping for convenient continuous operation.
  • M-Quick System for tool-free disc change at the touch of a button by means of M-Quick flange nut.
  • Restart protection prevents unintentional start-up after power supply interruption.
  • Electronic soft-start for smooth start-up.

Metabo features 

Our Maxitek Speedgrit range of cutting discs are manufactured and tested based on the European safety standards and the oSa trademark clearly signals to the user the high-quality manufacture and high stands of the safety testing.

The video below shows the difference between our Metabo and Speedgrit Combination compared to our competitor’s combinations. Look and see the results for yourself!


Satisfaction guaranteed... Or your money back!

If this combination fails to outperform your current combination in terms of performance or safety, we will credit you in full and you can keep the Angle Grinder and Speedgrit Cutting Discs.


Click below to view our exclusive offer.



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