Surface Plate

Scope This part of ISO 8512 specifies requirements for rectangular or square granite surface plates ranging from 160 mm x 100 mm to 2500 mm x 1600 mm, as preferred sizes, in four grades of accuracy O, 1, 2 and 3. NOTE 1 “Granite” is a commonly used description; a more specific description is given in clause 4. This part of ISO 8512 applies to new granite surface plates, granite surface plates in use, and those reconditioned according to their grade. 2 Definition For the purposes of this part of ISO 8512, the following definition applies. deviation from flatness of the working surface: The minimum distance separating two parallel planes between which the working surface can just be contained. 3 Nomenclature For the purposes of this part of ISO 8512, the nomenclature shown in figure 1 applies. 4 Material Surface plates complying with this part of ISO 8512 shall be made from stable, workable rock presenting a wear-resistant surface which does not tend to scratch steel surfaces. Igneous rocks such as diabase, gabbro and various other granites have been found suitable; they are commonly referred to as “granite” for the purposes of this part of ISO 8512. Rock used for surface plates shall be close-grained and of uniform texture, sound and free from flaws and fissures and from inclusions of softer materials. Repair of defects in the top surface is not permitted. The colour of the granite, which is dependent on the mineral composition, is of no importance, but the colour of any individual plate shall be uniform. NOTE 2 Some of the physical properties of granite used for surface plates are given in annex E. 5 Preferred sizes The preferred sizes for granite plates are given in table 1. If plates of other sizes are required, the requirements of this part of ISO 8512 shall nevertheless apply. The lengths of faces of plates shall be within +- 5 O/. of the nominal size. NOTE 3 It will be seen that the nominal lengths of faces, with one exception, are taken from the R5 series of preferred numbers; one plate, size 2000 mm x 1000 mm, is included because it is an established and widely used size, although 2000 is not an R5 preferred number. 6 Rigidity The thickness of granite surface plates shall be such that when a concentrated load is applied about the centre of the plate, the loaded area shall not deflect below the remaining area of the plate by more than 1 pm/200 N. The limiting value for deflection applies to surface plates of size 400 mm x 250 mm and larger.

Finish of the working surface The top (working surface) of grades O and 1 plates shall be finished by lapping, whereas grades 2 and 3 plates may be finished by lapping or left as ground. However, an item placed on it shall not wring to the surface of the plate. 8 General features 8.1 Supporting feet of surface plates All surface plates shall be supported on three feet. Plates larger than size 1000 mm x 630 mm shall have safety feet. Feet shall be positioned within the boundary of the working surface to minimize deflection. NOTE 5 The setting of adjustable feet may affect the deviation from flatness of the working surface; specific instructions for adjusting the feet are given in footnote 3 to table 1. Edge The feet shall be smoothly machined, but machining of the supporting feet into a plane parallel to the working surface is optional. 8.2 Projection of top If the purchaser so requires, the top of each plate may extend beyond the faces by at least 20 mm on plates of diagonal length up to 400 mm and by at least 25 mm for larger plates. The underside of the projecting surface shall be reasonably flat for accommodating clamps. 8.3 Surfaces other than the working surface If the purchaser requires the faces to be finished straight, mutually parallel and square, the tolerances shall be specified in the purchasing order. Side and end faces shall be finished smooth. All edges and corners shall be rounded with of at least 2 mm. 

We are manufacturing and servicing of Cast Iron Surface Plates to Grade 1 accuracy as per IS 2285-2003.Cast Iron Surface Plates used for layout, tooling, work holding, assembly testing & inspection. We offer wide variety of cast iron surface plate manufactured in compliance with international quality standards. Extensively used for tool making, inspection, spotting, gauging etc., these cast iron surface plates can be customized as per the specifications of the bulk buyers.

•  Hardness between 170 to 220 BHN.
• Box type ribbing pattern.
• Inspection by high precision level or electronic level traceable to NABL.
•  Stress relieved to relieve internal stresses.
• M.S. stands or C.I. columns with leveling facility can be supplied..
• All plates are provided with rexine protection cover

• Hardness between 170 to 220 BHN.
• Box type ribbing pattern.
• Inspection by high precision level or electronic level traceable to NABL.
• Stress relieved to relieve internal stresses.
• M.S. stands or C.I. columns with leveling facility can be supplied..
• All plates are provided with rexine protection cover
• Castings stress relieved to relieve internal stresses.
• Made from close-grained cast iron conforming to grade FG : 220,
• heavy ribbed and hardness between 180 HB to 210 HB
• Hand scraped surface finish

Good quality, close-grained, plain cast iron or alloy cast iron at least equal to grade 250 of ISO 185 shall be used; the material shall be sound and free from blow holes and porous patches. Minor defects in working surfaces of grades 2 and 3 only may be repaired by plugging with material of composition similar to that of the plate.

After being cast and rough machined, all plates of grades O and 1 and of size up to and including 400 mm x 250 mm shall be given a suitable treatment to relieve internal stresses before being tinished. H is strongly recommended that larger plates of all grades be stress-relieved by similar means; however, where facilities for this purpose are not available, such plates may be stabilized by natural ageing by agreement with the purchaser. The manufacturer shall, on request, supply the purchaser with a statement of the stress-relieving process which the plate has received.

Cast iron surface plates shall be made with adequate ribbing and the total depth [i.e. the combined thickness of the top (working surface) and the depth of the framing] shall be such that when a concentrated load is applied about the centre of the plate, the loaded area shall not deflect below the remaining area of the plate by more than 1 pm/200 N. The limiting value for deflection applies to surface plates of size 400 mm x 250 mm and larger.

Technical Specifications

GRANITE SURFACE PLATE

Grade: ‘0’

 Standard: IS 7327 – 2003

    Flatness Accuracy:  Grade 0

  Granite Texture: Fine

WE ARE MANUFACTURING OF GRANITE / CAST IRON SURFACE PLATES AS PER IS 7327-2003 AS PER IS STANDARDS. WE ARE SELECTED QUALITY GRANITE STONE AS PER IS 7327-2003 PROPERTIES.  

Surface plates complying with this part of ISO 8512 shall be made from stable, workable rock presenting a wear-resistant surface which does not tend to scratch steel surfaces. Igneous rocks such as diabase, gabbro and various other granites have been found suitable; they are commonly referred to STANDARDS.

The thickness of granite surface plates shall be such that when a concentrated load is applied about the centre of the plate, the loaded area shall not deflect below the remaining area of the plate by more than 1 pm/200 N. The limiting value for deflection applies to surface plates of size 400 mm x 250 mm and larger.

The top (working surface) of grades O and 1 plates shall be finished by lapping, whereas grades 2 and 3 plates may be finished by lapping or left as ground. However, an item placed on it shall not wring to the surface of the plate.

Two flatness tolerances are applied, one for the working surface overall and one for any local area of 250 mm x 250 mm of the working surface. A border zone, the width of which shall not exceed 2 “A of the shorter side with a maximum of 20 mm, may be excluded from these requirements for accuracy provided that no point on the border zone projects higher than the remaioder of the working surface of the plate.

We are manufacturing granite surface plate as per required  size with grade 0 accuracy as per IS 7327-2003 and rigid fabricated stand.

We are into manufacturing, supplying and servicing of Granite Surface Plates to Grade '0' accuracy as per IS 7327-2003. These plates are preferred for the inspection and layout making purposes. These surface plate make an ideal base for mounting sophisticated mechanical, electronic and optical gauging systems.We provide fabricated stand with adjustable leveling screws on request by our clients. The overall working height of surface plates with stand and leveling screw will be 900 MM (approx) from floor level

• Closed grained & uniform texture.
• Very hard, high wear resistance & extreme rigidity. .
• Outstanding dimensional stability.
• Top surface lapped smooth & flat.
• Inspected by electronic level, precision level & auto collimator traceable to NABL.
• Least subjected to internal stresses

Accuracy

Rigorous quality control inspection is carried out at all stages and final inspection is carried out with Electronic Level calibrated by an NABL accredited lab at regular intervals.

Material

Granite Surface Plates are made from select granite with uniform distribution of light and dark constituents. Granite used for surface plates should have the following physical properties.

Basis of Tolerances

• The values specified in table 1 are based on the following formula
• T = C1L + C2 Where
• T is the tolerance on deviation from
• flatness overall, in micrometres;
• L : is the nominal length of the diagonal of the plate rounded
• up to the next 100 mm;
• C1 and C2 are constants for the grade of plate and are given in table 1

We are into manufacturing, supplying and servicing of Granite Surface Plates to Grade '0' accuracy as per IS 7327-2003. These plates are preferred for the inspection and layout making purposes. These surface plate make an ideal base for mounting sophisticated mechanical, electronic and optical gauging systems.We provide fabricated stand with adjustable leveling screws on request by our clients. The overall working height of surface plates with stand and leveling screw will be 900 MM (approx) from floor level

• Closed grained & uniform texture.
• Very hard, high wear resistance & extreme rigidity. .
• Outstanding dimensional stability.
• Top surface lapped smooth & flat.
• Inspected by electronic level, precision level & auto collimator traceable to NABL.
• Least subjected to internal stresses

Accuracy

Rigorous quality control inspection is carried out at all stages and final inspection is carried out with Electronic Level calibrated by an NABL accredited lab at regular intervals.

Material

Granite Surface Plates are made from select granite with uniform distribution of light and dark constituents. Granite used for surface plates should have the following physical properties.

Features 

• Surface plates should be of high quality black granite having homogenous texture.
• Accuracy under load: surface plate should be capable of supporting a total normal load of 25 kgs. per 0.1 sq. mtr
• Surface plate should have lowest co-efficient of expansion resisting temperature changes
• Top surface should have smooth finish done by hand lapping to required flatness accuracy
• Bottom surface should be machine cut.

Reports

• Self-inspection report to be provided along with the material
• Surface plates shall be supplied with calibration certificate traceable to nabl

Stand

• Stand fabrication should be of heavy angle iron and to be reinforced for rigidity
• MS. stand should be painted with "smoke grey" colour
• Suitable anti vibration mount to be provided in the bottom

We are servicing granite / cast iron surface plate of any size as per standard accuracy with provide NABL calibration report.

We are into manufacturing, supplying and servicing of Granite Surface Plates to Grade '0' accuracy as per IS 7327-2003. These plates are preferred for the inspection and layout making purposes. These surface plate make an ideal base for mounting sophisticated mechanical, electronic and optical gauging systems.We provide fabricated stand with adjustable leveling screws on request by our clients. The overall working height of surface plates with stand and leveling screw will be 900 MM (approx) from floor level

The SPT can supply, on request, special inserts, steps and tolerances other than standard ones as per drawing