My 'A' Class SWORD has stimulated me to return to 'adjustable' spreaders.  Here is version 24.  The wider mast with a wider base on the 'A' allows a try at an 'obvious' solution of the sort seen on full-size.  The carrier is milled from Delrin, while the spreaders and the threaded body of the adjustment started life as 5 mm aluminium knitting needles.  The eyebolt is a standard 3 mm x 20 mm SAILSetc item.  The eye has been tapped to accept a M2 machine screw.

Spreader drawing

To make adjustments, unscrew the eye from the holder on the spreader, give it a turn in or out, and re-insert.  The next version won't need this;  I only need to figure out how to allow the body to turn without detaching it...

As before, the shrouds are clamped to the end of each spreader arm.  A shallow groove is milled so that the shroud, when clamped by the machine screw, doesn't get excessively compressed.

Spreader on mast

The "next version" is illustrated here, where a pair of proper bottlescrews are used for the length adjustment -- no un-screwing and re-screwing.  They work well!  (Render created with Autodesk's "Inventor" CAD software.  What a learning curve!)

Spreaders with bottlescrew adjustment

2007-09-04

©2024 Lester Gilbert