Manipulating and Bending thin wall bicycle tubing

[Rody]

Hey folks,

Many questions get asked about the best process to bend thin wall tubing without deformation or wrinkling of the tube's profile. I thought I would take a moment to share a few thoughts that I've found pertinent.

To successfully create perfect bends in thin wall tubing, regardless of material, requires tooling that meet a strict set of parameters;

- The tube must be fully encapsulated at the bend moment by the forming dies, supporting the circumferential walls of the tube.

- There must be a consistent, even draw pressure on the tube.

- Once the wall thickness moves below about .028", internal mandrel support is necessary to prevent the material from collapsing even with meeting the previous two requirements, especially in alloyed material.

With these three primary considerations met, it is possible to create acceptable bends in bicycle tubing for numerous applications.

So what "bender" do I buy? It is important to recognize that there is not one single tool that can accommodate every manipulation need in bicycle fabrication. I have five different tools to create the many bent shapes used in my frames;

- a custom C framed air over hydraulic bender for acute chainstay and seatstay profiles (Video 1)
- a modified JD32 bender for acute bends in forks, down tubes, support structures (Video 2)
- a custom 3 roll bender for long arcs used in seat tubes, top tubes, and some cruiser style tubing
- an Anvil roll bender for sweeping shapes in stay material where I am not creating tire clearance
- Various hand formers for small tubing such as racks, braces, and detail items

Just as there is no one tool that can do it all, it is important to remember that there is no substitute for the right tool...no amount of sand, ice, cerro bend, etc will make up for poorly designed tooling that lacks any of the previous mentioned requisite characteristics. Will these aids help a hobbiest cheat a manipulation in a home environment? Yes, but they have no place in the professionals arsenal.

Below are two short videos demonstrating distinct tube manipulations, both using titanium tubing.





As I create more video examples showing the other bending tools, I'll update this thread.

Best wishes,

Rody

[Shawn Pedersen]

Great video! Thanks for sharing.