Re: Re: Tube bending questions/advice for FNG
bushhog750 said:
I've highly considered that also. Just trying to hold out and see if I can learn the hard way before I drop even more money on the software. I just spent like $1300-$1400.00 on the bender, notcher and hydro kit so I'm trying to be a cheap ass for a few weeks. Lol
If you want to do it the hard way, you need to be good at math.
Every bend is a change in slope. A straight piece obviously has no rise, only run.
A 45 degree bend has 1:1 rise to run.
A 22.5 degree bend has .5:1 rise to run.
A 67.5 degree bend has 1.5:1 rise to run.
Any degree bend can be converted to rise and run to calculate where the tube will end up, and you can take rise and run and work backwards to find bend angle.
Then next math is figuring out the arc length of each bend.
Divide you bend angle by 360, to find your percent of a circle.
Multiple percent of circle by the circumference of the circle your bender makes. Find this out by calculating your achieved clr. Multiple 2 pie (3.1415) by your clr to find the circumference of the circle your bender creates.
This will tell you how long each bend will be.
If you keep a chart of every bend you make and the math for each, it makes it faster next time.
But, bend tech is worth every penny.
Another note, get some cheap 1 x 4 and 2 x 4 and rip them down the center.
This will give you 1.75" strips of wood. Cut them to length for each segment of straight tube.
But a screw between two pieces, at the center of where you want the bend. This gives you a complete model of what you want to build.
Also allows you to measure from end of the piece to each apex of each bend. The apex is the intersection of two straight pieces of tube, not including the radius of the bend.
To enter the info into bend tech for a custom part, you need the length, rotation and angle.
Obviously the rotation is 0, as the flat pieces of wood are all screwed together in one plane. Length is the measurement between end and apex, and apex to apex. Angle is the bend angle.
The wood model allows to to take a protractor and accurately measure the angle of each bend.
On a large hoop, keep in mind the part should be symmetric so bend angles on opposite sides should be identical.