Upon return from our Atlantic voyage we were in need of blocks. We had a complete kit of wooden cheeked plastic sheaved blocks in 2007. 10 years later each one is badly wounded. Many had the injection molded sheave buckle in the narrowed mid-section, sending broken sheave into the cheek and jamming the whole setup.

I want to go sailing, and as beautiful as the wooden blocks were, they require more time to construct and more time to maintain. I am a metal worker, so I fabricated 22 blocks with 1/4″ aluminum cheeks, solid/turned delrin sheaves 2 3/4″ in diameter, the sheave has a oil-lite bronze bearing pressed in, and the pins are 3/8 stainless steel bolts, spaced with 3/8 ID / 1/2 OD ss tube.

I purchased a metal lathe in the summer of 2016, and frankly I wish I had done so the day I finished my boat-shop. It’s been invaluable in fabricated bushing, bearings, repairs to windlass, rigging, etc, etc.

Sheaves

The delrin was sliced from a 36″ x 3″ 2 7/8 rod using a table saw with appropriate blade. It was then placed in lathe chuck and faced both sides. When this was complete i centre drilled and faced the outside radius. I then enlarged centre hole for press fit to lathe mandrel, Grooving of each sheave commenced at this point.

I borrowed some radius gauges and made myself a set of (lathe) cutters for the sheave grooves. I tried a single cutter but the diameter of 5/8 was often too much for my small lathe. So this was split into 2 half diameter cutters.

Despite the firm press fit for the mandrel, many of the sheave blanks continue to slip when any real cutter pressure was applied.

Block Cheeks, Pins and Axles.

I cut the aluminum cheeks from 3″ x 1/4″ flat bar, cut them to shape on a bandsaw, sanded all edges on belt sander, and them took them to a friend with a vibra-polisher to tumble them.