07-11-2021 comment

ISO 2538:1998 pdf free download.Geometrical Product Specifications ( GPS ) -Series of angles and slopes on prisms.
1 Scope
ISO 2538 specifies two series of prism angles from 120 to 0°30’ and a series of prism slopes from 1:10 to 1:500. for general mechanical engineering purposes.
2 Definitions
For the purposes of ISO 2538, the following definitions apply.
2.1
prism
part of a piece wtch is limited by two intersecting planes
See figure 1.
NOTE — Both pianes are temwd ‘piam plenes’, When these are intended for fits, they we termed mating planes for me prism
2.2
multiple prism
part of a piece wtch is limited by several pairs of Intersecting planes
See figure 2.
NOTES
1 A double prism Is lirisled by two peirs of itersecting planes.
2 When the witersechon of each pair of planes Is a point. Ihe multØe prism Is a pyrarmd (see llgure 3).
2.3
wedge
prism with a small angle
2.4
slid, prism vee-block
dovetail
typical prism with a large angle
NOTE — These special prisms are used. Par example, as a slideway on machine tools (see figures 4 and 5).
2.5
prism angle
angle at which born prism planes intersect each other See figure 1.
NOTE — The angle between the mating surfaces for prism is caSed maling angie for pesm
prism alofie
ratio of the difference between the heights H and I. in two determined cross-sectIons to the distance I. between both crosss.ctlons
See figure 6.
2.7
rate of prism
ratio of the cMleronce between the thicknesses T and i in two determined cross-sections to the distance 1. between
both cross•sectlons
c=LzL=2 tan
See figure 7.
2.8
prism edge
theoretical intersection line of both prism planes
centr. plan. of prism
plane passing through the prism edge which bsects the pflsrn angle j
2.10
height of prism
height measured at a given cross-section which Is parallel to the edge and perpendicular Ic one prism plane
See fIgure 6.
2.11
thickness of prism
thickness measured at a given cross-section which is parallel to the edge and perpendicular to the prism centre plane
See fIgure 7.
3 Values
Ang senes I and 2 as specified in table I are to be used in this order of preference
Table 2 is only to be used tot specisi applications as mentioned in the last column.
Table 3 shows the calculated values for slope and angle respectively and rate, corresponding to each recommended prism angle and prism slope.