Most of the popular nine inch (230mm)angle grinders on the market have a similar power rating and appear to perform as a concrete grinder with little noticeable difference.

However, beware of very cheap products where the bearings may not be of the highest quality because concrete grinding is hard on the bearings in particular.

Also, there is a difference with the efficiency of the motors so that one of the same wattage input will put out a different power to another.

Voltage

In countries where the domestic power is 240 Volts the 2400W and 2500W grinders are better than the 2300W models for Situp N Grind.

In countries with 110 Volts power, use 2300W models and limit the total number of weights on a Situp N Grind to 4 instead of 6.

Nine in (230mm)angle grinders

The best model is a 9 in (230mm) angle grinder because it runs at around 6,000 rpm and has powerful torque and strong gears. Situp N Grind attachments will fit all popular 9 in angle grinders using the spacers provided. The ideal speed of diamond segments for cutting is found with a 7" cupwheel at 6,000 rpm.

Seven in (180mm) angle grinders

are usually identical in appearance to 9 in angle grinders, but they run at around 8,000 rpm which is too fast for the diamond segments and not enough torque when you need it.

Do not use polishers as your main grinder for first-cut preparation because the gears may not be as heavy duty as a 9" angle grinder, however 7" polisher/sanders are excellent for polishing concrete. They are better suited for use with resin pads. Use them for first cut work on the edges only and fit them with 5 inch cupwheels. The 5" Cornerhood dust shroud can be fitted to most 7" polishers with the exception of Milwaukee because they do not have a bearing mounting boss.

Next page "Concrete Grinding Equipment"