Problem Subtracting Solid from solid Ver25

I am have an issue with this file. I am trying to subtract the Spiral Solid from the shaft solid. I select the shaft 1st, select the spiral 2nd, but it isn't subtracting the spiral from the shaft it is subtracting the shaft from the spiral. I want to end up with a spiral groove in the shaft. Can any one tell me what I am doing wrong?

Thanks,
Tom

What I would do is create only a section of your spiral, maybe 1 turn... Make that a solid and subtract.. If that works then undo and copy the spiral section down the shaft for number of turns needed. Then from there subtract each one...

Thanks Al, I will give it a try tomorrow. Any idea on why it won't work with the full spiral?

My guess is you created a swept surface...

And well it twists ....

So you would need to do a skin. But you cant skin the whole spirle just one turn, same reason the twist.