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Mast bending tool

On the first event I joined I got some tips and tricks about rigging and tuning my IOM. The most important one was that I needed to bend the mast forwards (in neutral state, so no stays attached) due to lack of tension in the rig. But bending the mast after drilling the holes needed for the rig is not something SailsEtc is recommending. Therefore I made a small tool with a couple of bearings and 3D printed rollers to fit the mast profile. With this tool I have bent my masts successfully with the same radius over the total length.

Are you interested in building your own tool to bend your mast? Here is the shopping list:

  • Rollers for 11mm mast
    Designed by me, available at Shapeways – Strong & Flexible Plastic was OK for the job
  • Do you want a roller for another mast? Contact me
  • Bearing 26x10x8 (Dxdxw)
  • Plywood for the basic construction (I used underlayment but I suggest something more robust)
  • Screws, bolts and nuts to fix the wheels

The roller in the middle need to be adjustable in height in order to adjust the bending radius with small steps. For the jig a slotted hole takes care of this.



I am no expert on the right amount of bending or the ideal bending radius for each jig. As a starting point I used the guidelines Graham Bantock from SailsEtc mentioned in his rig building instructions.


There are some points of attention while rolling the mast

  • Bend the mast step by step. It is better to repeat the procedure with a slightly adjusted middle roller than to correct the bending.
  • Be careful and bend the mast over 1 plane, don’t bend a S shape. Drill a hole trough the mast (or use the one for your spreaders) and insert the loose drillbit in the hole. Keep the drillbit parallel to the floor while feeding the mast trough the rollers.

Good luck!

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