Bend It Like Beckham (Not Like Benny)
So this week I made some more progress with the cage. Take into account, this is my first cage I've ever made. So with that said, it was a fairly expensive learning curve. I've been self taught with 95% of all the things I've ever made, so I always view my cost in "wasted" material as my tuition for my newly gained education. I got my bases of information from the forum Pirate4x4's tech section tutorial. It worked perfect for the main hoop (minus a few of my own careless errors) and then I combined my own method for the remaining parts.
Tools/Templates and jigs
JD2 Model 4 Tube bender & Hydraulic pump
JD2 TN-100 Tube Notcher (limited to 50* notches) Replaced with Raceline (JMR) TN300
JD2 1.5" Round Tube Die (cant remember which CLR I got though- I think its 5.5")
Templates and Jigs:
Various pre-bent tubes at different angles
Various tubes notched at various degrees
Small Diameter tubes to use as sleeves
Much like anything in life, they're many methods to do once task -- here's my method. For the main hoop I did exactly what was posted on the Pirate 4x4 link. But I also transferred my main hoop drawing onto cardboard to test fit inside the car to make sure it would fit as well as to save for a template. The rest of the process is the same so I will just include my pictures with brief descriptions.
The tape lines indicate where the bends start and indicate where to line up the tube on the bender. Placing the pre-bent tube over the cardboard hoop template allows me to mark where all the points will be to feed into the tube bender. Once it is all laid out, I measure from the center out how far those indications points are then transfer it to my straight tube I will bend. Mark ONLY the first bends at this time, marking the second bends prior to bending the tube will mess up the calculations due to shrinking and stretching of the tube when its radius bent (How I messed up tube #2 lol)
Always work from middle out. Measure the perimeter of your template and account a few extra inches on each side. Once cut, mark the midpoint and transfer the bent points onto the tube.
IE The top of my main hoop is 36" long. Midpoint is the 18" mark. Now my bend point starts at 14.5" so I mark the first bend points 14.5" from the center (both sides since we are mirroring it). Also I include the bend degree's and an arrow to indicate which way the tube will be stretched.
Since there are compound bends in the main hoop you want to make sure your bender is level, this way as you bend the tube, you can make sure the bends are level with each other
Looking closely you can see where I marked the bend point on the tube and die, this indicates the tube is set up in the correct location.
First bend complete. Now this is crucial that the tube is leveled, If it is not leveled and you make your next bend, your hoop will come out twisted. Once complete, place your 90* template bend on top of your the bar and transfer the bend points, measure the distance to the next bend point and repeat!
Traditionally I believe people make cages by measuring to the point where the bends start and draw out their layout like that. However, when you have a long radius bend, it can be difficult to mark exactly whats the best point to mark as the bend, especially if you are aiming to build the cage as tight as possible. So being more of a visual guy, it was easier for me to make a jig system where I could test fit various bends to get a better gauge where bends should be and at what degree.
For my pre-bent tubing, I have them bent in 5* increments this is plenty to give me angles for my base mock up and then I can fine tune the 1*-4* in my final.
Here is my A-pillar mock up. You can see the first bend starting at the front mounting plate, a tube sleeve to connect the second bend, then another straight sleeve to meet the main hoop. With this mocked up, I marked the space between the sleeves so I could take them out and transfer to my cardboard template.
With this mocked up, I marked the space between the sleeves so I could take them out and transfer to my cardboard template. Once I transferred the outline, I used my 90* bend tool to mark the bend points.
Now repeat the process! Measure the the length, account for some extra, mark the midpoint, mark bend points and bend! Note- the front of the A-Pillar bars are not resting on mounting plates yet, they still need to be trimmed. Since the connection of the A-pillar bar and main hoop is a little more complex I stopped here since I didn't want to botch the whole bar by screwing up the notch. So I bought the Pipemaster contour gauge tool to help determine the angle of this notch.
Here are my results:
Get it right, Get it tight.