Hidden tension in southern yellow pine

[gasman]

I was cutting some square section spindles for a bannister I am replacing at home. I had 8 perfectly 900mm long straight piece of SYP measuring 25x40 which I was going to cut in half so that each would make 2 at the final dimensions of 22x17mm. As the first piece of wood passed the circular saw blade, it gripped on the riving knife then as it reached the end, it sprang apart due to tension within the wood. The final bend in the 2 pieces was over 20 mm out of 900 - ie over 40 mm for the 2 pieces together. Unbelievable!
Just thought I'd share. Is there any way to predict this?
Thanks
Mark

 

[Steve Maskery]

That's bad luck. I've always thought of SYP as fairly stable.
What are you going to do now? Buy some more or use what you have? If you glued two pieces together you would have a more stable unit, I guess.
It's always infuriating when you go to all that trouble of machining stuff up nicely and then it goes and does a dance like that.
S

 

[woodbloke]

Is there any way to predict this?
Mark

Nope...just happens - Rob

 

[jimi43]

Good job you were using a riving knife or you might have been treated to a trip to A/E with a bannister sticking out of your head!

A classic case for those thinking about removing this safety device....DON'T!

Thanks for sharing!

Jim

 

[kmcleod]

I've had the same experience with SYP...spend ages getting it squared,,,soon as it hits the saw, it's banana time,,,

Absolutely no way to tell if its going to happen, and its darned frustrating,,,

:-x :-x :-x

 

[cerdeira]

Hi,

Is there any reason to go with that american pine instead of, say, redwood?
the times I've worked with redwood it has been fairly stable, specially the slow growth one.