Stand up edge grinder comparisons with Situp N Grind

Stand to Grind Edging Problems:

Most stand up, concrete-floor edge grinders are not effective because the wheels cause them to head into the wall instead of along it while some have rear axle skew adjustments that need to be altered too frequently.

When the edging section is at the front the wheels are a nuisance

This type of grinder cannot run along the wall edge properly

Offset Arm Edge Grinders

An exception are the expensive offset-arm, stand up edge grinders which have difficulty following the dips that are often found along a wall because the grinding wheel is suspended out on an arm and cannot be tilted.

They appear to be designed for a floor where the edges have already been flattened so they are probably great if all you want to do is polish edges that are already flat.

Offset stand up edge grinders are also slow because they exert a low force on the concrete floor and typically have a slow diamond cupwheel speed. They cannot be used in overlapping circles, and if they are used for concrete floor grinding in straight lines they will leave shoulder marks.

Kneel to Grind Option Floor Edger:

Kneeling to use a floor edger is a reasonable way to go except for the physical strain and frequent rest breaks that are needed.  Control is good until you move sideways on both knees while holding the grinder out in front. Edging this way is difficult and slow although it is the most common form of concrete grinding equipment.

Concrete grinding while kneeling

Situp N Grind

Edge grinding on a mobile stool with Situp N Grind

Grinding while sitting is the best:

The smoothest, fastest and easiest floor edger is a Situp N Grind. This is because it is pulled smoothly along a wall without stopping to change knee positions and because you can see everything clearly while operating this concrete grinding equipment close to the floor. There are no dust trails and you have complete control sitting over the top of the angle grinder.

View a movie here of edging with Situp N Grind (0.9mb)

To move along you just push gently with your legs and let the stool move you backwards along the wall in a continuous, flowing motion as you float the grinder along.

When concrete floor grinding Situp N Grind can be floated in circles which reduces the amount of grinding marks (shoulders). Sitting above the grinder allows for circular movement easily as well as an instant change in direction if needed.

For storage the side handle can be quickly taken out and stored alongside it while the entire grinder can fit easily into any vehicle boot/trunk.

For more information see Concrete Floor Grinder

Productivity is reduced with kneel-down floor edger as fatigue sets in

When you kneel down to do concrete floor grinding you can move quite quickly... for a short while anyway.

The main problems are just physical ones:

- sore back, aching shoulders, numb hands from vibration, damaged knees and don't forget your sensitive eyes are very close to the action. The biggest physical problem is exhaustion and slow down for frequent breaks

... and exhaustion leads to mistakes, which is something you do not need on a job.

Productivity can be reduced by 50% with most

stand up edgers because they only grind one way

If you use a stand up edge grinder with two wheels attached it only grinds in one direction (forward) so it is only 50% productive. It must be pushed forward and then pulled backward, but it only grinds on the forward motion.

Stand up concrete grinder only grinds in one direction

Large motors are not always faster

Did you realise that large, stand up grinders with a big motor that still use domestic power are slower than Situp N Grind and do not bite into the floor or follow the dips as well because they cut too wide a path and their motors do not have high torque so you cannot put much weight on them.

Then again, there are the narrow, stand up, floor grinding equipment where a heavy motor sits on top of a 9" disc. These are quite productive, even close to Situp N Grind performance and they are easy to use except for edging and confined spaces, but they leave grinding marks (shoulders) because they cannot be floated in a circular motion.

The large planetary concrete floor grinders that use the same power source are very close to Situp N Grind performance on softer concrete only, but they progressively fall behind as the floor hardness increases because they lack the power, motor speed and torque of an angle grinder.

It is difficult to beat the tremendous torque of an angle grinder, the 6,000 rpm disc speed and up to 22 lbs (10 Kgs) of weight on a 7" (180mm) disc.

Situp N Grind is the most productive 240V grinder

Situp N Grind is the most productive floor edger and concrete floor grinder because it works 100% of the time with very little physical effort. It is mostly used in overlapping circles and leaves only minor shoulders, it has no safety problems, you are close enough to see what you are grinding and it will do the edges beautifully.

All that makes it much faster than any comparable grinder design and about half to one third the cost of most.

View floor edger comparisons video (0.8Mb)

Storage space required

A kneel-to-use grinder is the best for storage - no question.

Most stand up grinders are a painful storage problem with high handles on an angle so they take up lots of space. Situp N Grind is easy to store and takes up only a small space.

Control = quality

Angle grinders on a stand up frame with two wheels and a long handle have the least amount of control as seen in the "edging comparisons" video above. They generally cut a straight path leaving straight grinding shoulders on the floor.

Edge grinders with the head on a long, offset arm are the next hardest to control. They do not ride up and down on the bumps easily because of the long distance between the head and the wheels.

Large head, single and double grinders leave strong shoulders as they are swayed from side to side or moved forward and backward so control of them is perhaps medium.

Planetary grinders have good control in a single direction.

Situp N Grind has excellent control in any direction which can be changed in an instant to suit the variations encountered on any floor.

Visibility = productivity

This is very, very important to prevent going over floors a second time because of missed areas in dips. When you cannot see the floor for dust you will miss many of these areas on your first pass.

Standing upright is a little too far away for good visibility even with lights.

Kneeling is great for visibility, but not too safe for the eyes.

Sitting to grind is by far the best because you can see everything very clearly so you will not miss spots although your eyes are nowhere near the grinding disc and without dust trails you can clearly see what needs to be ground and when it has been ground satisfactorily.

Confined spaces work

Believe it or not kneeling to grind is more difficult in confined spaces than sitting to grind because of the distance of the legs from the grinder being held in front of the body.

Stand up grinders are not suitable in confined spaces such as bathrooms or toilet cubicles because of the long handles and their inability to move quickly in any direction or to spin around and change direction.

Probably a combination of a small, 5" kneeling handgrinder and a Situp N Grind would be best combination for confined spaces.

Go to the next page "Floor Grinder"