oak stock material bowed badly once ripped

[Glenbirnie]

I am making an overlight above double sliding doors in oak. Due to oak costs Ive bought all material in at the machined sizes I need for accuracy and speed apart from vertical glazing bars. I am ripping 36mm square offcuts to produce 15 x 36mm. When I did this on a 1 metre off cut is has sprung badly, the pieces look like barrel staves.

Is there any way round this or should I have bought in 15 x 36.

I know wood has stresses etc and I understand why this happens Im wondering if I should be looking at the grain and cutting a certain way. ie if Id turned this test piece 90 degrees and cut might it not have happened?

Thanks

 

[Dave54]

No real way to tell. Sometimes it cuts really well, and other times it springs. Try turning it as you suggest, but with machined up pieces like you have you are nearly always going to get some movement. Oak quality was getting worse and worse when I was buying it up to about 4 years ago. Most of the English Oak seemed to have disappeared, leaving (IMO) inferior European oak most of which appears to be from the outer part of the tree.

 

[Burnerman]

+1
Timbers can be stable for years and retain it's shape......put it through a saw and it can warp on all directions.
I made a fireplace from Iroko a while back......acquired from a 30 year old lab bench top. Started to cut it, and the pieces twisted like a dogs back leg
John

 

[big-all]

i had a 4.2m long bit off rough sawn 8x2"
first 3" rip strait as a die
second 3" rip a bit off a bow
the remaining 1 3/4" x2" would have made a great propellor or cork screw

as said you dont know what will happen this is why you cut rough saw to size
you can machine strait lengths as one
select any bits with cups twists or bows cut to length for short sections machine individually to minimise waste

 

[AronSearle]

Poor drying can cause stresses.