JASH Cast Iron Straight Edges are widely used for setting up and leveling machinery and for checking and spotting bearing surfaces during hand scraping operations. Properly supported, they may be used with various indicating devices to check surface flatness of large machined areas like Surface Tables, Machine Tables and Bed, Machine ways etc.

SALIENT FEATURES:

Offered in two types viz Bow shaped or Camel Back Type and I-section or Parallel type, in standard sizes generally as per IS-5268 – 1991.
Box shaped straight edges are provided with pads on their bow for supporting Engineer’s level.
Made from close-grained plain cast iron conforming to Grade FG: 220 of IS: 210 – 1978.
Castings stress – relieved to remove internal stresses.
Offered in three Grades of accuracies viz Grades 0, 1 and 2 Standard sizes, dimensions, flatness and parallelism tolerances are as stated in table.
Straightness determination done by inclination Method as per clause 4.2.3. Of IS: 12937 – 1990 Indian Standard on “Engineering Metrology – Methods of Testing Straightness Flatness and Perpendicularity”.
Straightness accuracy checked by Electronic level. Computer print out of the contour of working surfaces is furnished.
Hand scraped surface finish for Grade 0 and 1 straight edges. Smooth machined / ground / scraped surface finish for Grade 2 straight edges.
High spots uniformly distributed proportion of bearing area of the working surface not less than 20 percent for Grades 0 and 1 straight edges and not less than 10 percent for Grade 2 straight edges.
Flatness of side faces: Any 300 mm length that within 25 microns for Grades 0 and 1 and within 50 microns for Grade 2, subject to the maximum tolerance on flatness over the whole length, as under.
For straight edges upto and including 4000 mm length, 50 microns for Grades 0 and 1 and 100 microns for Grade 2.
For straight edges longer than 4000 mm – 100 microns for Grades 0 and 1 and 200 microns for Grade 2.