Assemble the Stretcher Frame
1. Lay out the braces so the widest part of the frame is toward you (if applicable). If the braces cross, put the side with the screw head(s) facing down at this time.
2. With the "canvas side" of the stretcher bar (see cross-section diagram, above) facing up, attach one of the longer stretcher bars to the bottom of the braces by sliding the slot in the braces over the bracket.
3. Attach the right stretcher bar to the bottom bar and horizontal brace. Use a mallet to tap the joints into place.
4. Attach the top stretcher bar to the right bar and vertical brace.
5. Attach the left bar to the top and bottom bars and horizontal brace. Tap all bars together with the mallet so that all joints are fitting tightly and the frame is assembled square.
6. Flip the stretcher frame over so that the "canvas side" is now down. Your frame is now ready for stretching the canvas. See our instructions for How to Stretch Canvas for more information on this step.
7. Before stapling the canvas onto the frame, check that the frame is square by measuring diagonally, which should be equal. If necessary, use the mallet to gently tap on the corners to adjust squareness.
8. After the canvas is stapled to the frame, place two keys in each corner and one key at the end of each brace. Tap all keys in with a hammer to expand the frame incrementally and evenly until desired canvas tension is achieved.