Summary

Attaches to a chain saw handle (with a diameter of approx 25mm) to help cut firewood logs at proper length.

Instructions

See picture for the part in action. With this part, it's a lot easier to cut logs at proper and equal length.

Rotate 90 degrees before printing so the nut pocket faces upwards.

You need an M5 nut and bolt, a thumbwheel ( e.g. http://www.thingiverse.com/thing:728871) and a 5mm thick metal rod.
The nut might be a somewhat thight fit in the nut pocket.

Measure 30 cm (or however long you want your logs to be cut), perpendicular to the chainsaw blade, and cut the metal rod at the proper length.

Chainsaw log/wood measure device.