{"id":263342,"date":"2024-10-19T17:33:01","date_gmt":"2024-10-19T17:33:01","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/bs-978-11968\/"},"modified":"2024-10-25T13:22:07","modified_gmt":"2024-10-25T13:22:07","slug":"bs-978-11968","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/bsi\/bs-978-11968\/","title":{"rendered":"BS 978-1:1968"},"content":{"rendered":"

This British Standard relates to involute spur, helical and crossed helical gears, having diametral pitches finer than 20, in four accuracy grades. Examples of application are:<\/p>\n

Class A<\/i>. Astronomical apparatus and scientific instruments; colour printing machinery; control systems (when multiple trains of gears are involved this grade would generally be used for low speed components where the effect of positional accuracy is important).<\/p>\n

Class B<\/i>. Navigational instruments; high speed components of control systems where quietness and smooth running are essential; machine tool speed control; photographic instruments.<\/p>\n

Class C<\/i>. General purpose instruments; accounting and calculating machinery; counters; clockwork mechanisms.<\/p>\n

Class D<\/i>. Textile machinery; switch operating gear; clockwork mechanisms where accuracy is not the primary consideration.<\/p>\n

It is recommended that all spur, helical and crossed helical gears for use in horology should be produced to this British Standard with the possible exception of gears for weight or spring-driven mechanisms in which the pinion is the driven member and has 12 or fewer teeth. In such cases it may be preferable to use gears conforming to BS 978-22)<\/sup>.<\/p>\n

Gears of pitch range greater than 20, up to 200 diametral pitch. Standard pitches; two basic racks (one with backlash allowance); modification of addendum and centre distance to suit various conditions. Four grades of accuracy with elemental and dual flank composite test tolerances. Appendices: single flank testing, calculation of measuring pin dimensions, calculations for various design conditions.<\/p>\n","protected":false},"excerpt":{"rendered":"

Specification for fine pitch gears. – Involute spur and helical gears<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
BSI<\/b><\/a><\/td>\n1968<\/td>\n36<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":263343,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2641],"product_tag":[],"class_list":{"0":"post-263342","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-bsi","8":"first","9":"instock","10":"sold-individually","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/263342","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/263343"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=263342"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=263342"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=263342"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}