Threaded Axles


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Introduction

Threaded axles can be useful for many purposes. Two of them I will present here. The first is how to build supports that can be used for example in crane models and the second is how to use threaded axles for a constant movement in a specified direction.


Supports

Support with threaded axle

The first important thing you should know about threaded axles is that they are not as tension-resistant as normal Technic axles. Therefore I use them just in applications where they have to support pressure and no tension.
One of these applications is the use as a support for a crane model. In my third mobile crane I used four of them as supporting legs. This way they direct the pressure forces in the support arm and from there into the chassis of the crane.
By screwing them up or down, you can adjust the height individually.
There are two different types of nuts for the threaded axles. The older ones are threaded over the whole lenght. But there are also the newer ones which are just threaded over about the half of their length. Therefore I recommend to use always the older ones because they can support greater forces.

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Constant Movement with Threaded Axles

Constant movement with threaded axles

Another interesting application of the threaded axles is to use them for constant movement in a specified direction. This technique I use in my Kalmar forklift truck to adjust the width of the forks.
It is not possible to create great forces with this system because of the weakness of the axle and the nuts. Another fact is that they are made of ABS and not of steel. Nevertheless they do their job in this application very good. (It is not possible to adjust the width if there is a load on the forks.)
This system works similar to the one used in vises. To propel it, I use a micromotor. Because there are two forks in my model, I use a micromotor for each side. But it is also possible to do the same thing with just one motor.
To better understand the whole thing, jump to the building instructions which describe how to build adjustable forks for a forklift truck.

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