A Vernier depth gauge is used to measure the:

Explanation:

Vernier depth gauge:

• The construction of a vernier height gauge is similar to that of the vernier caliper except that it is vertical with a rigid base.
• It is graduated on the same vernier principle which is applied to the vernier caliper.
• It consists of an upright steel beam fastened to a steel base.
• The beam is graduated with the main scale in mm as well as in inches.
• The main slide carries a jaw upon which various attachments may be clamped.
• The jaw is an intergral part of the main slide.
• Vernier height gauges are used in conjunction with the surface plate.
• In order to move the main slide, both the locking screws of the slide and the fine adjusting slide have to be loosened.
• The main slide along with the chisel pointed scriber has to be set by hand, for an approximate height as required.

• The vernier height gauge is mainly used for layout work.
• It is used for measuring the depth of a blind hole.
• It is used for measuring the width of the slot and external dimension.
• The vernier height gauge is used with the dial indicator to check hole location, pitch dimensions, concentricity and eccentricity.
• It is also used for measuring depth, with a depth attachment.
• It is used to measure sizes from the lower plane with the help of an offset scriber.