What Hole Diameter Do I Need For A GroundGrabba to Screw Through?

We often get asked what size or diameter hole is needed for a GroundGrabba to pass through. We have two widths of GroundGrabba flights of the GR13 Model which covers the GroundGrabba Pro, Pro I and Pro II.

You need a slightly smaller hole when talking about a thin material like sheet metal compared to a thicker material like timber.  With thinner material like sheet metal, the GroundGrabba can wind through like a screw but with a thicker material you won't be able to do that.

In timber, you'll need a 1” or 25 mm hole, for the flights of the Pro to go through. If that material is mounted or sitting on the ground, you could basically just drive your GroundGrabba Pro straight the way through. 

For the GroundGrabba Pro I and Pro II, you'll need a 1 3/8 inch or 35 mm hole, and then the flights will drive all the way through without obstruction.

With the thinner materials like sheet metal, you can start off with a ¾” or 19 mm hole for the GroundGraba Pro, and it will screw through at an angle.

The GroundGrabba Pro will also fit through larger holes too of course.

Our GroundGrabba Lite is larger again. Although it can screw through a 1 3/8" hole (35mm) it is tight, so best use a hole larger  1 34" however, the GroundGrabba lite is not suited for holding down plate steel or timber.

With the PRO I and PRO II through thin metal you'll need at least a 1” or 25mm hole to screw through. 

There is a challenge associated with a hole size larger than the Collar under the Hex Head size of 25mm. The diameter of the head and collar are very close to the same size as the hole and therefore can slip through. 

To prevent the collar of the Hex Head slipping through, we've created a special washer called the "HookWasher". 

To use the HookWasher, it's very easy. Just hold the HookWasher on a bit of an angle then slowly screw the flights of your GroundGrabba through the tear drop shape and then slide it up the shaft.