Adjustable spreaders (19)

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Yet another idea for adjusting the spreader "V".  My 19th.  Really...  I think this one shows excellent promise.  The spreaders are held between two plates at the mast.  The schematic shows adjustment for "V" angle using a screw.  In the sketches on the left, the adjustment screw works with a captive nut.  In the sketches on the right, the adjustment screw works within the tapped spreader.

The first part of the illustration shows how the spreaders for my A class "Bakers Dozen" work.  The 2.5mm adjustment screw passes through the end of the spreader carrier and to a nut.  The nut is held captive, and as the screw is turned it pulls the spreader carrier forward or eases it aft.  The nut, and the spreader carrier, is held between two plates.  The plates are 2mm thick, and their gap is 5mm, the size of the nut across its flats.  The nut is a nylok.  The adjustment screw in fact has a nylon thumbwheel at its head for finger adjustment.  The thumbwheel, slightly dished, bears against the aft edge of the plates.  Different spreader lengths can be inserted into the carrier arms, and are bolted in place.  The carriers are milled from 8mm rod, and the spreaders themselves are 5mm dia (cut down aluminium knitting needles).  The end of the spreader is tapped for a clamp screw to hold the shroud.  A small groove is milled in the end face of the spreader to improve the clamping action.

The second part of the schematic shows a lighter version for my IOM, pictured below.  The two plates, 1.5mm thick, have been lightened with holes and are 4mm apart.  There is no captive nut.  Instead, the end of the spreader is tapped for the 2mm adjustment screw.  As with its heavier version, the adjustment screw has a nylon thumbwheel at its head, which bears against the aft edge of the plates.  The spreader is a 4mm dia aluminium knitting needle, and is turned down to 3mm along its middle section.  The spreader end is again tapped for a 2mm shroud clamping screw.


2011 Lester Gilbert