Variance from 45 sawing

[esarratt]

My understanding is rift sawn lumber is 30-60 degrees to the rings and quarter sawn is 60-90 degrees.

Is lumber that is sawn perfectly at 45 degrees to the rings the most stable?

How much can one vary from 45 degrees before stability starts to become sacrificed?

[Tom the Sawyer]

I don't think you could get a board sawn "perfectly at 45 degrees to the rings", since you are talking about flat planes intersecting with curved planes.  If the center line of a board intersected with the rings at 45 degrees, the angle of intersection would be different on both sides of the center point.  IMO, "rift" is more sought after as an appearance factor.  Quartersawn is generally considered more "stable", but it depends on what type of stability you are seeking.

You would likely get more answers by posting this in the sawmills and milling section, it really doesn't have anything to do with urban and community forestry.

[Southside]

Like Tom said, as a rule QS is the most stable and has the least shrinkage.  Look at the old heart pine flooring, all QS / vertical grain.  What is it you are wanting to produce?

[esarratt]

Shingles cut on a bandsaw.  I was wondering if a little more effort (I have the wood) would increase the longevity.

[Don P]

For a shingle its just like a rived shake, quartersawn would give the best service.