I've got a summit tubing bender, (only $9!) and I get the basic idea of the marks with the degrees. What I don't get is what the R, L and related tick mark are for. I'm guessing it has something to do with how much the bender drags the tubing through, to allow you to figure out how to place the bend where you want it. It didn't come with any instructions, and I don't want to waste a bunch of tubing trying to figure out how to read it. Anyone know how it works?

Bend to template or make a pattern ie bend to fit

dont worry about degrees

Oh yea you mentioned you dont want to waste tubing... but I recommend you send a few feet to the scrap heap while you learn how to use a tubing bender..

The result if you dont sacrifice some tube.. is some tube youll have to throw away

i got the same bender from summit ..... it fell apart within 10 minutes.

Those benders from Summit are made for aluminum, copper, or brake-line grade steel tubing only... don't go near DOM or Chrome-Moly with them, and same thing for stainless..