tomstaf Posted August 3, 2014 Share Posted August 3, 2014 Hi, I'm wanting to make some digger type arms work. On the real thing they're moved by pneumatic double cylinders. I've been looking around and see that various model diggers (mainly in Germany) have been made to work but they seem to use a motors and wires. I want to make the 2 arms move left and right and should have enough space to make them move left/right with a micro servo. As you can see there are double cylinders mounted on top to raise and lower the arms. But as you can see wires and pulley would look odd making the cylinders work. I was thinking about solenoids but don't know if you can slow down their action, and then wondered if memory wire would do the trick? Aside from them, is there any suitable electronic component which would do the action? Cheers Tom Link to post Share on other sites More sharing options...
raymw Posted August 3, 2014 Share Posted August 3, 2014 Hi Tom, What diameter are the cylinders in the model, and the stroke? Best wishes, Ray Link to post Share on other sites More sharing options...
Titan Posted August 3, 2014 Share Posted August 3, 2014 If you have the wires running through the cylinders it can be very unobtrusive and convincing. Many years ago I saw a layout on which someone had managed to motorise the backhoe on a 4mm scale Airfix JCB using wires. It had an exceptionally realistic action - Dig the trench, lift, slew, empty bucket in adjacent dumper, slew back and repeat. It remains to date in my mind as the best bit of layout animation I have ever seen. Link to post Share on other sites More sharing options...
tomstaf Posted August 3, 2014 Author Share Posted August 3, 2014 Hi Tom, What diameter are the cylinders in the model, and the stroke? Best wishes, Ray Hi Ray, The thicker yellow cylinder scaled down is 2.7mm and the silver arm is 1mm. If the stroke is how far the arms extends that's 8.5mm Cheers Tom Link to post Share on other sites More sharing options...
raymw Posted August 3, 2014 Share Posted August 3, 2014 I think I would try thin piano wires, in plastic tube, in the back of the cylinders connected to the 1mm rod. Move them with servos hidden wherever you can in the cab. A memory wire system may be smaller, but I've not found it easy to work with. I think it's a bit small to try and wind coils within the cylinders themselves, Best wishes, Ray Link to post Share on other sites More sharing options...
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