Cast iron square box

A cast iron square box is a specific six working face cavity cube made of cast iron or steel,with a V-shaped groove on one of the working faces.Mainly used for inspecting and marking the parallelism and verticality of components.Each working surface of the square box must not have rust,scratches,cracks,dents,or other defects that affect the measurement performance.Non working surfaces should be sandblasted and painted with chamfered edges.There should be signs on the inner wall of the square box,indicating the specifications,dimensions,level,factory number,and manufacturer name.

Verification method for cast iron square boxes:For square boxes with a side length of 315mm and below,1mm measuring blocks are placed at both ends of the inspected surface of the square box during verification.A knife shaped ruler is placed on the working surface of the measuring block,and then a measuring block is used to test the plug at each inspected point.The difference between the size of the equivalent block group just inserted and the size of the measuring blocks at both ends is the deviation between the inspected point and the two ends.This calibration should also be carried out on several cross-sections of the square box working surface in the longitudinal,transverse,and diagonal directions.When the error direction in the measured straight lines at each position is consistent,the maximum value is taken.When the error direction is inconsistent,the sum of its large positive and large negative differences is taken as the flatness of the tested surface plane.

Precision of cast iron square boxes:For scraped square boxes,in addition to verifying flatness,contact spots should also be inspected using the coloring method.The number of spots in any square with a side length of 25mm is:level 1,level 2,not less than 25 points;Level 3 with no less than 20 points.

Precautions for using cast iron square boxes:

1.Before using the cast iron square box,clean it with pure gasoline and wipe it clean with gauze.At the same time,check whether there are any rust,scratches,cracks,scratches,dents,sand holes,and impurities that affect the quality of the square box on each working surface to prevent affecting the measurement accuracy.

2.The working faces of the cast iron square box are processed to maintain mutual verticality and parallelism.Therefore,the square box is mainly used for fastening and positioning the workpiece.It provides an auxiliary reference perpendicular to the reference plane for the measured workpiece.By flipping,the measured dimension is perpendicular to the platform(flat plate)working surface,achieving platform measurement.Therefore,when using,the square box should be placed on a clean platform(flat plate),continue to shake the guide rail,and other reference planes.

3.After using the cast iron square box,it should be cleaned and wiped clean,and coated with anti rust paint.