My son is about to go camping, and wished for snatch blocks to hoist bear bags into trees more easily. I suggested that we had the stuff around the house to manufacture this ourselves, and make it much lighter (useful for camping) than the expensive high-load snatch blocks available for sale.
- 1" polyethylene rod
- ½" aluminum rod
- ½" x ⅛" aluminum strap
- 2 x M5*8 pan-head screws
- 2 washers
Lathe: Used a 10mm round carbide insert as a form tool to make a pulley. Drilled it ½" through. Drilled and tapped ½" aluminum rod ¾" deep M5 (because I have appropriate M5 screws), parted it off ¾" long. This is a bushing.
Mill: Two pieces: Cut ⅝" and ½" holes at opposite ends of the aluminum strap, about 3" long. (The ½" hole about ½" from one end, and the ⅝" hole about ⅝" from the other end. ⅝" is just because it was a good match for some carabiners we have; choose hole size and corresponding placement to match.)
Vice: Bent the aluminum straps together near the ⅝" hole ends so that the ⅝" holes touch.
Put loctite in both ends of the aluminum rod.
- M5 screw
- Screwed into bushing rod
- One strap over bushing
- Pulley over bushing
- Other strap over bushing
- Other washer
- Other M5 screw
- Tightened solidly onto loctite
(On this first pass, the ½" holes are closer to the end than the hole diameter because we changed our mind about design partway through, and I could have rounded the edges on the straps. But for a quick and dirty low-load snatch block set, I was pleased.)