It's cheap and very easy!
Step 1: Need!
1. Square aluminum tube without 1 wall
3. Bolts and 2 nuts
Step 2: Drill Hole!
Ignite blade as shown in the photo on the site drill hole.
Step 3: Cut!
Ropes width depends on how much incised
Step 4: Screw a Pin!
Insert knife and screw a pin as shown in the photo