A.長(zhǎng)約50mm,錐度為1:20,大端比管孔大0.025~0.05mm B.長(zhǎng)約40mm,錐度為1:25,大端比管孔大0.025~0.05mm C.長(zhǎng)約40mm,錐度為1:20,大端比管孔大0.025~0.05mm D.長(zhǎng)約50mm,錐度為1:25,大端比管孔大0.025~0.05mm