Talk:Pattern (casting)

Latest comment: 3 years ago by Doug butler in topic Contraction allowance

i want the knowlage about core mouldry; —Preceding unsigned comment added by 117.102.0.71 (talk) 15:51, 26 March 2008 (UTC) Reply


User 122.174.141.251 asked in the "Shake allowance" section "What does this even mean?". I removed it from the article as it's really a talk question, not part of the article. Can anyone help him or her? Barney Stratford (talk) 19:31, 30 September 2016 (UTC)Reply

Contraction allowance edit

"if a bush were required to be 1500mm O/D, 1000mm I/D and 300mm high using a 2% contraction rule: The Patternmaker would make the pattern 1530mm O/D, (as it will contract in), 980 I/D (as the inside diameter will contract outwards) - important to note the Inside Diameter has 20mm taken off it rather than added to it". I dispute this statement. The item when cooling would retain its shape, so the bore I/D will contract at the same rate as the O/D. This is how a ball race is shrunk onto a shaft. Thus the pattern I/D would be 1020 not 980. Or am I missing something ? Doug butler (talk) 01:36, 8 November 2020 (UTC)Reply