……………….BS 8888

Dimensiynu

Dimensioning

……………….BS 8888

Dimensiynu Cyfochrog / Parallel Dimensioning

Nifer o dimensiynau yn cychwyn o un llinell tafliad

Several dimensions originating from one projection line

……………….BS 8888

Dimensiynu Cadwyn / Chain Dimensioning

Dim ond ei ddefnyddio os nad yw’r darn yn cael ei effeithio gan goddefiant cynyddol

Only to be used if the object is not affected by the accumulation of tolerances

……………….BS 8888

Dimensiynu Cyfuno / Combined Dimensioning

Dimensiynu sy’n cyfuno cyfochrog a chadwyn

Dimensioning that combines parallel and chain

……………….BS 8888

Dimensiynu Cylchoedd / Dimensioning Circles

A) Dimensiynu tu fewn i’r cylch / dimensioning internally

B) Dimensiynu tu allan i’r cylch / dimensioning externally

C) + D) Dimensiynu tu allan os yw’r cylch rhy fychan /

External dimensioning if the circle is too small

……………….BS 8888

Dimensiynu Radiws / Dimensioning Radii

A) Dimensiynu gyda canol y radiws ar y gwaith / dimensioning with the centre of the radius on the work

B) Dimensiynu radiws heb angen lleoliad canol y radiws / dimensioning a radius that doesn’t require the location of the radius centre

C) Dimensiynu radiws sfferaidd / Spherical radius dimesioning

……………….BS 8888

Dimensiynu Tyllau / Dimensioning Holes

……………….BS 8888

Dylunio Edau / Drawing ThreadsA) Pan yn dylnuio edau or pen, maer llinell adau yn cael ei ddangos gan cylch sydd wedi torri

A) When drawing threads end on, the threaded line is shown by a broken circle

B) Yn aml fydd edau yn cael ei ddangos tu fewn i rhan gan llinell wedi torri

B) Frequently a thread will be shown inside a part by a broken line

C) Dyma sut i ddylunio edau ar ddyluniad trychiadol

c) This is how to show a thread on a sectional drawing

……………….BS 8888

Esiamplau gwerthoedd Ra gwahanol / Rules of Thumb for surface finish in Ra values Turnio garw – medru gweld y marciau / Rough turned with visible toolmarks....Ra = 12.5μm (micro.m)

Peiriannu llyfn / Smooth machined surface....Ra = 3.2 μm (micro.m) Greindio / Surface Grinding… Ra = 1.6 μm(micro.m)

Gwynebau Lapio Llyfn / Fine lapped surfaces.... Ra= 0.025 μm (micro.m)

BS EN ISO 1302:2002 Geometrical product specifications (GPS). Indication of surface texture in technical product documentation

Dangos GARWEDD ar luniadau Peirianneg - Showing ROUGHNESS on Drawings

The information below is taken from the British Standards 1302 for labelling diagrams to describe the surface finish:

Mae’r gwybodaeth isod wedi ei tynnu or British Standards 1302 ar gyfer labelu diagramau er mwyn ddisgrifio garwedd

Example showing the symbol being used on an engineering drawing

Esiampl o ddiagram yn dangos y symbol ar gorffeniad