GripIt GDOTDAB20 20mm Plasterboard Undercutting Tool– Suitable for Brown Gripits (20mm)

Update to review: Picked up a set of allen/hex keys and just wanted to broadcast that the diameter of the grub screw on this, which is used to adjust the depth of the under cutter, is 1.5mm. So I can now, finally, use it!Original review: So far I'm unimpressed. I can't actually use it as the item has come fixed to a depth that is less than the thickness of my plasterboard, doesn't come with an allen key to adjust, none of my allen keys fit it (not even the smallest) and there's no indication on the packaging of the correct diameter allen key to use!

Fitted Gripits to put a TV on the wall.I didn't know that the walls in my place had insulation on the back of them, so I needed this tool to get a channel for the gripit wings to open out.Reading the reviews, it seems the main whinge is the small size allen key needed to adjust the depth of the tool (if needed), and the users didn't have one to hand.. I'm not sure if 1.5mm is really that unusual, I had a couple, and I just did a quick check on allen key sets for sale on Amazon, and they seem to be a standard part of a metric set. Anyhow.. be prepared that you may need a 1.5mm allen key to make adjustments! (I did leave a star off, because if one was included, it would be better, and I'm sure for the cost of a few extra pence, would be better.Use wise, pretty straightforward.. load up in a drill and grind away.. I would keep pressure on the bit, and once done, let it come to a complete stop before releasing the pressure and pulling it out. The reason for this advice is to keep the thickness at the required depth and minimizing the chance if could be less, and potentially causing a weak spot.Depending on what you are actually cutting/milling, it could get quite messy, in my case, it was insulation, and some plaster board and it went everywhere.Probably never going to be used again, but the job is done.

If it fits, so if your plasterboard is 1 cm thick, it should work ok. Although I would also say: it's hard to tell whether it's at correct depth, as the cutting tool bites into the plaster anyway, so still moves around, making it hard to tell whether you have it set to correct depth. Probably best to measure the plasterboard thickness after drilling the initial hole, then set the undercutting tool - if you can adjust it, that is. Yes, depth is adjustable, but not only do they not include the tool you need for this, but they also don't bother mentioning what size hex key you need - it's different for different size undercutting tools.. I saw reviews, saying you need a 1.5 mm hex key, so thought I'd be ok, but the size required for the 20 mm undercutting tool is around or below 1 mm, definitely smaller than 1.5 mm (which is correct size for 25 mm undercutting tool). I bought the 20 mm and 25 mm sizes, as have needed both in the past, but for this job, I needed the 20 mm undercutting tool and was annoyed to discover that my smallest hex key was still too big. Luckily, I had also ordered geefix plasterboard fixings, as don't require undercutting. With those, the part that goes behind the plasterboard is long and narrow, and can be positioned vertically or horizontally and depth is fully adjustable, so no undercutting required (although had to increase the hole size). While a lot more expensive per fixing, they're also stronger, as the weight is spread out over a larger area and easier to use. They can be used where GripIt's can't. Undercutting tools will doubtless still come in handy, once I've sourced the correct size hex key, that is. So unless your plasterboard is 1 cm thick, you'll need a micro hex key set including sizes below 1.5 mm - or look at alternative fixing options and avoid the need for this..

Unfortunately this is getting a 1-Star review despite being a very good tool. The reason, as mentioned by most reviewers here, is tha Grip-It don't include a 1.5mm allen key to adjust the tool. Which is daft. And they have been a bit sneaky in their advertising where they state on the packet "Adjust depth plate of undercutting tool to plasterboard thickness". They should add " *not included." Because I thought I had everything I needed to hang my TV I drilled the holes, went to undercut the dot and dab, and then had to leave it a week while I sourced a the appropriate allen key. Inconvenient. Shame because the tool works fine otherwise.

Really?! The package makes no mention of the need to buy a specialist Allen/Hex key of less than 1mm if you need to adjust the depth of the undercut. Such sizes are not in a 'normal' toolkit and thus you'll have to source one separately. Quite frankly, I'm not sure how the manufacturer can sell them without all the gear required to actually use them. How much would it have cost for them to include the right size tool for adjustment? Far less than the product itself that's for sure. Fit for purpose? - Of course not. Not so much a fire breathing dragon, but more a flowery Snapdragon. Note to manufacturer - sort this out before you lose sales.

All the instructions say to “adjust the tool to match your plasterboard depth” but don’t supply the very small Allan key needed. I went to Homebase and even a 1.5mm didn’t do it so I said f*** it and just used it, and it turned out ok. Poor though as when you buy the actual gripit’s, you get the hole saw you need.

I used this to undercut on a dot and dab wall to mount a TV bracket. Reading other reviews, the main issue seems to be the 1.5mm allen adjustment collar. I have a good few sets of allen keys and 1.5mm is included in all of the metric sets. The ability to set the depth is important, one reviewer assumed it was already set at the correct depth, this would not be possible as plasterboard comes in different thicknesses and you also have to include the layer of plaster on top which can also vary.I drilled 6 x 25mm holes for the blue Gripit fixings and only a couple needed to be undercut where the dabs were, so I set the depth of the tool against the back of the plasterboard through one of the holes that did not require undercutting. All in all a great little tool for using with the gripit fixings, and not expensive either.