All of our products use kiln dried basswood. Most stretcher bars use a two part construction with meshed-tooth joinery that ensures dimensional stability for museum-quality stretchers and strainers. Lip sizes include 1 1/8, 1 1/2, 2 and 2 1/2 inches deep (custom depths up to 3" available for an additional cost.)
Our more cost effective product is a strainer. It comes in standard and heavy duty stretcher bars that both share 2 1/2 x 7/8 inch crossbars. Strainers have all joints glued and nailed together so they are unable to be keyed out or taken apart. For a more in depth explanation please look at the wikipedia page
https://en.wikipedia.org/wiki/Strainer_bar
corner joint of a heavy duty strainer
We do not make traditional stretchers that are keyed with wooden triangles. Instead we make mechanical stretchers using an innovative fastening system that holds expanding miter joints tight when expanded. Mechanical stretchers are only made with the heavy duty body.
corner of a mechanical stretcher
video showing how the mechanical stretcher works