How do you use a tap backnut box spanner?

Step 1 – Select right size tool

To select the correct box spanner for your needs you will need to know the size of the nut you want to turn.

Nearly all backnuts are 1/2 or 3/4 inch. Their AF (across flats) measurements are typically  27mm and 32mm.

Step 2 – Position yourself comfortably

Once you have a box spanner of the correct size, place yourself in a comfortable position where you have good visibility of your work area (this may be difficult as tap backnuts tend to be in awkward places).

Step 3 – Align box spanner with tap tail

Align the box spanner basin wrench with the tap tail and move it upwards over the tap tail (you will have to have removed the supply pipes to do this).

Step 4 – Fit box spanner over nut

Move the box spanner upwards until its hexagonal socket fits over the tap backnut.

Step 5 – Rotate tool

Rotate the box spanner. Turn it clockwise to tighten and anti-clockwise to loosen.

You can increase your leverage by inserting the T-bar handle through the holes in the end of the box spanner and using that to turn the tool.

Warning: if your backnut is made from brass then be careful that you don’t overtighten, as this could seriously damage your basin. If the backnut is plastic then overtightening could result in splitting your backnut.

Step 6 – Remove nut

Once you have sufficiently loosened the nut, you should be able to remove it easily by hand.

Removing stubborn nuts with a Stiffnuts box spanner

Step 1 – Select required attachment

There are multiple socket attachments for this tool, so you will need to know what kind of nut you are working with before you assemble the attachments.

Step 2 – Slot in required attachment

Once you have the right socket attachment, slot it into the orange end of the body of the tool.

Step 3 – Screw tool onto tap tail

Slide the tool up over the tap tail and screw it on to the threads until it reaches just below the nut you want to remove.

Step 4 – Engage nut by hand

Lift up the socket attachment part of the tool and engage it with the nut, hand tightening until secure.

Step 5 – Disengage and rotate tool 180°

The socket attachment part of the tool will now stay on the tap tail and will be engaged with the nut.

You can now disengage the body of the tool and rotate it 180° so that the yellow end is now facing upwards.

Step 6 – Engage opposite end with socket attachment

Engage the yellow end of the tool with the socket attachment that is secured to the nut.

Step 7 – Rotate tool anti-clockwise

Rotate the body of the tool anti-clockwise. This action will engage the socket attachment and unscrew the nut from the tap tail.

You can do this either by hand or with an appropriately-sized T-bar handle (not supplied).

Step 8 – Rotate with drill (optional)

You can rotate this tool via a power drill to make life that little bit easier.

This is optional, but if you do, make sure your drill is on its lowest torque setting.