Rubber Ball to Open and Close case Backs Ø65 mm, black, white, Open

Friction does the work here instead of steel keys. We mould this hollow ball from supple rubber to take the shape of screw-off case backs under direct downward palm pressure. Turn it by hand once seated to start or finish the thread.

Rubber friction body

The hollow sphere yields under steady downward force. It settles into the contours of the case back and grips the flat metal across the full contact area.

Palm grip control

You press down with the open hand and twist. Because no steel pins engage the notches, torque comes straight from friction between the rubber skin and the case metal.

Starting the thread

When closing a case, the ball turns the back until the threads seat cleanly. You feel cross-threading early through the soft material before tightening down fully.

Bench storage care

Keep the rubber free of bench oils and fine swarf so the outer surface stays tacky. Wipe the skin clean with a dry cloth before each use.