Making a Block and Tackle Wooden Pulley System

Since my shop is so small, I store a lot of the larger tools in my attic. And I've grown tired of twisting my back hauling the air compressor or the winter tires up and down the ladder, so I've made this pulley system.

It multiplies the force four times and most of the components are rated for 1/4 metric ton or more, so it should be good enough for my tools.

But I can't be sure how safe a hoist like this might be so I don't encourage anyone to make one. It's for my personal use and you should not do dangerous things.