Hi,
I am quite new to machining and metal work in general, and I'd like to ask for some advice about making a round tapered (cone shaped) aluminum tube. The tube in question is meant to be a mast for a sailboat, 5.5 meters in length, 70 mm in diameter at the bottom, gradually tapering to around half of that (35 mm) at the top. Tapering is done in order to save weight, which is important for sailboat stability - every gram counts. Wall thickness of said tube would probably be 3 mm.
Shape requirements are pretty relaxed. The tapered profile does not have to be perfectly round - it can have some teardrop shape, although the closer to the round, the better to resist sideway bending forces.
I am exploring options on how to manufacture such a tube, considering that there are no such tubes readily available for purchase (yes, I have looked up flag poles, street light poles, etc., but they are never the right dimensions).
I have considered making a "stepped" reduction in diameter (making this mast from sections of different diameter aluminum tubes that slide inside one another, like a fishing pole), but the required overlap between these tubes to have sufficient strength in the joints overcomes any weight savings of the tapering, making overall weight even higher. Additionally, these "steps" would create a lot of inconveniences when raising and lowering sail on the boat.
My idea - not sure how realistic - is to take a 70mm x 3mm tube, split it lengthwise with a V-shaped gap. This gap would be near-zero width at the point where the taper starts (around 1m above the bottom end of the tube),and then gradually get wider towards to the top. Then, the idea is to press the tube with clamps so that the edges of this gap would come into contact, and then weld them together again. The difficult part would be clamping this tube with sufficient force and precision.
Can anyone comment on this, do you believe this is a realistic approach to turn a round straight tube into a tapered tube? If not, can you suggest any alternatives to make tapered aluminum tube that are possible to do with typical DIY tools? I have angle grinders, welding equipment, 1 ton hydraulic press, a lathe (not large enough for 5.5m long tube, though!), and some other typical equipment, but no special machinery for this task.
I am quite new to machining and metal work in general, and I'd like to ask for some advice about making a round tapered (cone shaped) aluminum tube. The tube in question is meant to be a mast for a sailboat, 5.5 meters in length, 70 mm in diameter at the bottom, gradually tapering to around half of that (35 mm) at the top. Tapering is done in order to save weight, which is important for sailboat stability - every gram counts. Wall thickness of said tube would probably be 3 mm.
Shape requirements are pretty relaxed. The tapered profile does not have to be perfectly round - it can have some teardrop shape, although the closer to the round, the better to resist sideway bending forces.
I am exploring options on how to manufacture such a tube, considering that there are no such tubes readily available for purchase (yes, I have looked up flag poles, street light poles, etc., but they are never the right dimensions).
I have considered making a "stepped" reduction in diameter (making this mast from sections of different diameter aluminum tubes that slide inside one another, like a fishing pole), but the required overlap between these tubes to have sufficient strength in the joints overcomes any weight savings of the tapering, making overall weight even higher. Additionally, these "steps" would create a lot of inconveniences when raising and lowering sail on the boat.
My idea - not sure how realistic - is to take a 70mm x 3mm tube, split it lengthwise with a V-shaped gap. This gap would be near-zero width at the point where the taper starts (around 1m above the bottom end of the tube),and then gradually get wider towards to the top. Then, the idea is to press the tube with clamps so that the edges of this gap would come into contact, and then weld them together again. The difficult part would be clamping this tube with sufficient force and precision.
Can anyone comment on this, do you believe this is a realistic approach to turn a round straight tube into a tapered tube? If not, can you suggest any alternatives to make tapered aluminum tube that are possible to do with typical DIY tools? I have angle grinders, welding equipment, 1 ton hydraulic press, a lathe (not large enough for 5.5m long tube, though!), and some other typical equipment, but no special machinery for this task.