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© 1977 to 2008 Splat Publishing Ltd
DATELINE: August 2008
John Disborrow Clockmaker and gentleman,
by
Brian Loomes.
For head or hand A fascinating Lenzkirch movement,
by
D K Stevenson.
The floating balance Robust and tolerant,
by
Brian Barkworth.
Overwound! A common problem analysed
by
Alf Wilford.
West Dean appoints
new horology tutor Matthew Read has been appointed as Programme Tutor on the Conservation and Restoration of Antique Clocks programme at West Dean College, to follow Roger Still’s retirement.
Penman's Design & Build Cutting rack teeth,
by
Laurie Penman.
American Notebook Clocks as decor,
by
D K Stevenson.
Sundial Page A 'Moorish' dial,
by
Christopher Daniel.
Diary of a Clock Repairer The fragility of clocks,
by
Robert Loomes.
Invariably, replacement pendulum bobs purchased from suppliers do not fit existing pendulum flats. It is not easy to remove excess lead from the flat hole within the bob. Filing a fit is frustrating since Swiss files, even the coarest cuts, quickly clog with lead particles. The use of a steel drift to enlarge the hole is also beset with problems, not least the removal/release of the drift, usually resulting in an enlargement of the mouth of the hole for the pendulum flat. I looked in Agricola's De Re Metallica and Moxon's Mechanical Exercises hoping to find inspiration, to no avail.
Then I remembered that wooden plane makers used coarse toothed rasps to clean out blade and wedge holes in moulding planes. Small 'flat' rasps are no longer made, so I made my own from a piece of brass strip, see sketch. The cutting eeth are made using a small cold chisel and held as indicated. The cuts have sufficient strength to cut away lead and do not block. These float rasps work best on the pull-back stroke.
Derek D Clabburn more tips
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