doesn’t necessarily have to make a board longer. Making a board wider into a panel is also “stretching the board”. Attention to detail is all that is needed in this basically simple process. A few key points to attend to will yield beautiful panels for your work. Here are tips from WOODCRAFT on the subject:
https://www.woodcraft.com/blog_entries/ ... ess-panelsYour attention to the small stuff and detail will be rewarded
Note that there are two schools of thought about spring joints both valid to their adherents, go with what you believe in and are familiar with that gives you your desired results.