Adjustable spreaders (23)

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Iteration 23 is an improvement on iteration 17 of adjustable spreaders, adding a small mast fitting which helps the arms bear cleanly against the mast.  The milled angle is now 30 rather than 45.  And there is no folded washer to hold the shrouds.  These performed better for me at the 2006 IOM Nationals, in that they were quicker to adjust and to remove and replace than the versions I had been trying recently.

Each end of the spreader arm is milled to a 30 degree angle.  On one arm, clearance is milled for a M2 machine screw to screw into the corresponding tapped M2 hole on the other arm.

The mast fitting clips onto the mast and provides a smooth bearing pad for the spreaders.  The 25 mm machine screw has had its head turned down a little to improve clearance.

The other end of each arm is tapped to take a short 5 mm long M2.5 machine screw.  As in version 17, the now slightly larger machine screw clamps the shroud against the spreader. The M2.5 hole is relieved, which seems important to allow the screw to properly "bite" the shroud and clamp it securely.  The 30 degree milled surface at the shroud end of the spreader arm, parallel to the milled surface to the mast end, allows the shrouds to remain more or less vertical as the spreader arm is rotated to increase or decrease the spreader "V".

2006-09-06


2011 Lester Gilbert