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Post by Clinton Cool on Mar 26, 2024 1:02:54 GMT
I've designed the surfboard rack for the bike. The plan is to use 27mm tubing and key clamp fittings. The front bit will be fitted (only when needed) to the tank protector bars. These are 25mm steel, very strong. There's a handy unused lug with a hole in it on the frame of the bike, towards the rear. A nice strong fixing point for the rear part of the rack. Again, the rack will only be fitted when I need it.
My plan is to use steel tubing for the most stressed parts i.e. the horizontal members. I'll use aluminium for the u cradle bits as this will less stressed. Using this combination the front and rear members weigh in at 2.6 kilos each. A bit less actually, as this includes the fitting which attaches to the bike. The surfboard weighs around 6-7 kilos.
I've few doubts that the 27mm steel will be strong enough. I made some industrial style tables using 34mm tube. This was tough as hell. I couldn't bend it even a mm at a 1 metre length, using all of my strength. These sections will be around 300mm long.
The aluminium tube has a wall thickness of 2.5mm. I've never used aluminium so I'm less sure about its strength (or lack of). My instinct is that 27mm x 2.5mm will be more than strong enough. It will only need to support the weight of the board. Any additional stress, maybe caused by riding into a pothole or something, should only effect the horizontal, steel parts. I'm not sure about it though. Any opinions as to how strong aluminium is, do my choices of materials sound safe?
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Post by on Mar 26, 2024 7:06:27 GMT
I'd use thick wall aluminium (3.2mm or more) and worth considering Stauff pipe clamps. They can be used to transition from a tube to a flat part or something which the tube needs bolting to.
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Post by Aloysius on Mar 26, 2024 12:29:56 GMT
You can't beat a good stauff clamp.
A large consignment of stauff clamps was sent to Gaza but Hamas used them for terrorist purposes. There is now an international embarguo on stauff clamps across much of the Levant.
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Post by Aloysius on Mar 26, 2024 12:31:10 GMT
Titanium has a greater tensile strength.
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Post by Aloysius on Mar 26, 2024 12:42:12 GMT
Incidentally for purposes of quick fix and detach cunning arrangement consider the use of rivnuts which is a portmanteau word using rivet and nut
One could make handy dandy butterfly bolts with only the minimal use of a stick welder and use clutch springs to prevent vibration moving them.
Stick welders are quite cheap these days.
Also known as SMAW welders. I do not know what smaw is an acronym of.
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Post by Aloysius on Mar 26, 2024 14:24:58 GMT
Pipe bending is fun. And the results are often aesthetically pleasing.
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Post by Aloysius on Mar 26, 2024 16:20:30 GMT
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Post by thebfg on Mar 26, 2024 16:52:38 GMT
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Post by Aloysius on Mar 26, 2024 17:13:13 GMT
Would like to see a sketch of the concept though.
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Post by Clinton Cool on Mar 26, 2024 17:38:29 GMT
Cheers for all the ideas. Following consulation with around 10 people in total I think my original plan is a goer. However: my plan to bolt a single lugged bracket key clamp to the lug on the frame with the hole in it, isn't. My plan was to use this to contain and support a horizontal length of steel tubing taking the arrangement rearwards before constructing the 'u' arrangement to hold the surfboard. Doing things this way would mean that just a single bolt would need to prevent the weight of the rear rack, and at least half the weight of the surfboard from swivelling the arrangement downwards. Dangerous, not good enough. It would be better to weld the key clamp to the lug on the frame. I was hoping to avoid welding if possible, but safety is better than suffering the decline in value of a strangely adapted bike.
It was suggested earlier that it might be worth me buying a cheap welder. They seem to be around 60 quid or so. I've always been a bit nervous about welders. Angle grinders too. Angle grinders for good reason but with welders I've never used one, I'm a but nervous about the heat and loads of sparks everywhere. Is there really anything to fear?
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Post by on Mar 26, 2024 17:41:10 GMT
Stauff clamps are good.
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Post by Jim on Mar 26, 2024 17:44:49 GMT
Cheers for all the ideas. Following consulation with around 10 people in total I think my original plan is a goer. However: my plan to bolt a single lugged bracket key clamp to the lug on the frame with the hole in it, isn't. My plan was to use this to contain and support a horizontal length of steel tubing taking the arrangement rearwards before constructing the 'u' arrangement to hold the surfboard. Doing things this way would mean that just a single bolt would need to prevent the weight of the rear rack, and at least half the weight of the surfboard from swivelling the arrangement downwards. Dangerous, not good enough. It would be better to weld the key clamp to the lug on the frame. I was hoping to avoid welding if possible, but safety is better than suffering the decline in value of a strangely adapted bike. It was suggested earlier that it might be worth me buying a cheap welder. They seem to be around 60 quid or so. I've always been a bit nervous about welders. Angle grinders too. Angle grinders for good reason but with welders I've never used one, I'm a but nervous about the heat and loads of sparks everywhere. Is there really anything to fear? practice on scrap metal, make a.sculpture, whatever. The art is in striking the arc then maintaining a constant gap as the weld progresses and the rod gets used. Probably best to get a box of quality general purpose rods, 3mm or so, usually better than the Lidl/Aldi stuff. Auto switch masks are a boon too, not that expensive. If it ends up looking like a pigeon shat on your work, grind it off and repeat. |
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Post by dogless on Mar 26, 2024 17:52:18 GMT
Keep seeing the thread title so had to be done
Rog
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Post by Aloysius on Mar 26, 2024 17:54:46 GMT
Wot e said. Loads of 'hey gang let's do some welding' YouTube vidz. Some of them are good.
Stick with smaw (haha). And a rule of thumb is, 'did the weld hold after hitting it with a hammer'?
Totally go for it. Practice with scrap.
BTW welding to the bike frame not a good idea. Stick with clamps. But if you decide to do it anyway remove the battery and ignition unit first. Maybe the reg-rec as well.
The key clamps of which you speak look quite good, I have to say.
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Post by Clinton Cool on Mar 26, 2024 18:16:13 GMT
Keep seeing the thread title so had to be done Rog Very good! |
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