Gearbox [GB]
One turn of the central gear drives the four compression screws of the cell at once, for a homogeneous mechanical closure.
Mechanical pressure on four screws
BETSA® offers the membrane as the standard pressure maker for its M-DACs. Pressure can also be built up with four compression screws, either by hand or with a gearbox.
The gearboxes are made for users who chose a diamond anvil cell with the clamp screw option. A single rotation on the central gear distributes the movement over the four compression screws of the DAC, so the closure stays homogeneous on all four at the same time — unlike a manual closure, which has to be done crosswise.
To know the closing distance, the upper part of the gearbox is graduated: it controls the degree of central rotation that is transferred to the external gears.
The four compression screws can be supplied with four right-hand threads, four left-hand threads, or two right-hand and two left-hand threads mounted in opposition, depending on the cell.
![BETSA® Gearbox [GB] mounted on a diamond anvil cell](/wp-content/uploads/2026/07/betsa-gear-box-gb-140-2xx-01.webp)

