# Shear stress in a pinned shaft

So I am trying to figure out this shear stress problem that I have no idea how to approach. I have a shaft which is transmisitting a torque. It can be locked to its housing by using a pin which passes through it radially. I need to know that the shaft wont snap when transmitting its torque when unpinned however, and do not know how to solve this problem. I found the stress concentration factor for such a model, but I don't know what equation to use for max or average shear stress, this is beyond my understanding of stress, and beyond all the texts i have my hands on.

## Answers and Replies

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You need to post quite a bit more detail.

Is the shaft solid or hollow?

Does the pin transmit the load?

Is the pin tapered, a cotter or what?

If the pin does not transmit the load, is there a keyway, spline, flat or what?

A simple sketch would help enormously.

sorry, been staring at it soo long everything sounds obvious, I am sure you know the feeling.

it is a solid shaft with a hole drilled through it from the side. I am not worried about failure of the pin, but failure of the shaft it passess through when the pin is removed. it is a plain cylinder shaft undergoing pure torsion.
Code:
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|         |
|    o    |
|_________|
i can do a picture in a bit if that drawing is not enough. It is a very simple stress concentration problem, but it is one i have never seen before and can't find reference on.

Well I would have hoped a mech engineer? could have provided better information but still, here is the formula you require from my stress conc tables.

You realise that the max shear stress occurs at the outer surface and that your shaft is only at risk if the hole is between the load and the drive?

go well

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