Types of grinders
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The final choice you make will depend on the size of the job and the type of material you need to remove.
In corners and tight areas, you can use a hand held grinder.
These purpose-made grinders have a dust shroud and extraction hose, unlike an ordinary angle grinder.
It's important to use these attachments when you're grinding concrete and generating a lot of dust.
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Most floor layers use machines driven by mains electricity - either 240 volts or three phase.
However, petrol, diesel, LP gas and compressed air are sometimes used to drive larger models.
The most common types of heads are single, double and planetary action, but it's also possible to get four headed grinders and other configurations for large projects.
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Single headed grinders
These grinders have a central shaft that drives a single head.
On smaller machines the head comprises one disc, often with a diameter of 250 mm.
Larger machines can take three discs in a range of diameters, generally up to 250 mm each, which gives them a grinding width of 550 mm or more.
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However, these machines are designed more for concrete polishing rather than preparing a surface for a floor covering.
Depending on the type of tooling you're using, the disc will have slots, holes or other mounting fixtures to take the diamond segments or plugs.
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Double headed grinders
As the name suggests, double headed grinders have two shafts, and each one takes one or more discs.
On some machines, the shafts are counter rotating - that is, they rotate in opposite directions - to balance the torque and make the machine more manoeuvrable.
Other machines allow both heads to rotate in the same direction.
These grinders tend to pull to one side, which is a characteristic that can be put to good use when you're working along a wall.
The grinding width typically ranges from about 750 mm to 1000 mm.
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Planetary action grinders
The idea of a planetary action grinder is to enable the large planetary head to rotate independently of the grinding discs - or 'satellites' - that are mounted to it.
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This has the effect of increasing the speed, and therefore the aggressive nature of the cut, when the diamonds are closer to the outside of the head.
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However, counter rotation is not used when grinding the floor in preparation for a covering.
Learning activity
Audio 9 (mp3 |6|KB)The video clip below demonstrates the action of a counter-rotating planetary grinder:
Concrete grinding machine - Planetary Pro Genie
Watch the video and answer the following questions:
- How many diamonds does this three-headed machine hold?
- How is the tooling secured to the grinding discs?
Now go to a promotional video produced by HTC Professional Floor Systems at:
Select the second video clip in the first column, called: 'Each HTC Greyline grinder presented'. Watch the video and answer the following questions:
- What type of grinder is the first machine? (That is, describe its head configuration.) What is its grinding width?
- What type of grinder is the last machine? What is its grinding width?
Go to Diamond tooling