It confirms that tempering quality after being circle checked is the main cause for deformation of the steam seal ring made by rolling.

通过分析，确认校圆后的回火质量是钢板卷制汽封圈产生变形的主要原因。

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The quality of London watches was facilitated by hundreds of shops exclusively dedicated to threading screws or tempering springs or piercing jewels.

FORBES: Big Time: The British Pocket Watch