The jeweling caliper rest was manufactured by many different makers of watchmakers' lathe, including Clement who termed their version the "the quick-change combined lathe attachment". The writer has never used one but its reported function was to help with the difficult job of forming the recesses to hold jewels or bushes.  Instead of measuring the diameters needed, the jewels or bushes are used as templates. The Clement version was - in the usual overblown publicity language of that company - claimed to be "12 attachments in one - 30 advantages besides - at 1/5 the price. Fitted to any make of lathe"

The Clement version of the jewling caliper rest was - in the usual overblown publicity language of that company - claimed to be "12 attachments in one - 30 advantages besides - at 1/5 the price. Fitted to any make of lathe"