在螺丝上加垫片用英文怎么讲

题目

在螺丝上加垫片用英文怎么讲
椅子的扶手上有螺丝固定,我们想在螺丝和扶手中间加垫片,应该怎样描述呢?
add a washer at the screw for arm
add a washer between screw and arm
我觉得这两种句型都有点怪怪的,

答案

The arm of the chair is fixed by the screw,we plan to add the washer between the arm and the screw for fasten the screws.