5 Tips for Choosing and Sawing Wood Stock

Over several decades of working with steam-bent wood, I’ve developed some tips and guidelines for choosing and sawing stock. Following these points, I have timbered out many boats without breaking a single frame.

David Stimson

A tapered white-oak butt log, with measurements being taken from the bed of the sawmill to the top of the log to ensure that the log’s top surface is level.

1. Use the Butt Log

About 50 years ago my mentor, Mert Long, taught me that one should use only lumber from the butt log; wood from higher up the tree will be stiffer and hence more difficult to steam-bend.

2. Look for Wide Growth Rings

I have found that wood with wide growth rings is more pliable and less likely to break than wood with tight rings.

3. Saw the Wood Flat-Grain

The wood should be sawn flat-grain, so that the annual rings are parallel to the plane of bending. In practice, however, some of the stock is likely to have rings that are at an angle to the plane of bending—sometimes as much as 45 degrees. These pieces can be used in places where the bend is less severe.

David Stimson

The first few cuts are made parallel to the outside of the log to avoid grain runout.

4. Custom-Saw Parallel to the Grain When Milling

Butt logs generally taper from top to bottom. To avoid grain runout, which will weaken a frame, the stock must be custom-sawn parallel to the grain when milling the log. The first cuts should parallel the outside of the tree. As one gets closer to the heart, sacrificial wedges must be removed to keep the grain parallel.

If one does not have the luxury of custom sawing, extra stock should be purchased and pieces with grain run-out set aside for floor timbers and other members where straight grain is less important.

David Stimson

As the cuts approach the center of the log, the tapering of the grain diminishes; a wedge is removed from the log to compensate for this.

5. Don’t Forget to Steam

Hardwoods should be steamed for 45 minutes to one hour per inch of thickness. Cedar planking should not be steamed for more than 15 minutes per inch; if steamed longer it will swell, only to shrink and leave a gap in the seam after drying. And your carefully spiled whiskey plank will refuse to go in and you’ll have to find something else to do with that bottle of spirits that you’ve been saving for the occasion!

 

David Stimson designs and builds wooden boats in Warren, Maine.