Surface Gauge : definition and uses - Electrical4u

Definition Surface Gauge

• Surface Gauge is a Adjustable Stand For Marking off casting and Tasting the Accuracy of plane surface with used of Surface Plate.

• This contains a square shaped base with a vertical spindle attached to it. A small bush with a projection is fixed on it which can slide by loosening the wing nut with Surface Plate. 

Uses Of Surface Gauge

• It is used to draw layout lines at a set height from the base, thus it is also known as draw surface height gauge. 

• The work piece is held at an angle plate so that, it is perpendicular to the surface plate. 

• The scriber block is then adjusted to the required height and used to scribe a parallel line by sliding the table along the table's surface. 

• These can be used as limit pins to allow the blocks to press against the edge of the table, controlling its movements in that plane. 

• The upright post can be adjusted to tilt backward or forward, effectively moving the scriber point up or down in a controlled manner. 

• Coarse adjustments is made by sliding the scriber along with Clamping Block.

Types of Surface Gauge

Generally, two types of surface gauges are used :

1. Fixed surface gauge
2. Universal surface gauge

Fixed Surface Gauge 

• Also known as scribing block, it consists of heavy flat cast iron block fitted with a vertical steel rod. An adjustable device carrying a knurled screw at one end and a hole for scriber on the other is fitted on the steel rod. The scriber can be tightened or loosened, using a rod by the aid of knurled screw at a position Sliding bit upwards or Downwards along the. A surface gauge is mainly used for locating the center of the round bars held by the V-block, by making straight lines and by tilting the job through various angles. It is generally used along with a surface plate or marking table.

Universal Surface Gauge

• It is the improved type of fixed surface gauge and is more accurate than the fixed surface gauge. In this surface gauge, the pillar or spindle can be adjusted by scriber nut. Scriber can be moved up and down by means of rocker arm. This arm consists of spring at one side and fine adjusting screw at another side. Fine adjusting can be done by means of a screw. The base is made of cost iron. 'V' shape of groove is cut on its base. The guide pins are fitted in the base of this surface gauge. These guide pins are helpful for scribing lines from any datum edge. The scriber can be clamped at any position on the spindle with the help of a snug and a clamping nut.