When grinding glass with different thickness, the wheel head can be raised or lowered fast with the air cylinder to change its position or change the heads.
在先磨削不同厚度的玻璃时，磨头可利用其气缸快速升降，以迅速改变磨轮位置或更换砂轮。
2
She has limped home on one cylinder a few times and once with a grindingwheel bearing.