Moving along with the frame saw project—once you cut the mortise and tenons for the arms (what I'm calling the horizontal boards that hold the blade) and stretchers, it's time to work on the blade-holding mechanism.
One end of the blade will be held in place with a lag screw (minus its head). The other end will have a carriage bolt.
Both the screw and bolt need to be sawn down the middle along the last inch or so of their lengths. Then you need to drill a hole through them that lines up with the holes that are located at each end of the blade. (The blade that I bought from Highland Hardware had holes, otherwise, you'll have to drill them yourself.)
These sets of holes are for crosspins, or screws, or nails—whatever you'd like to use to keep the blade from falling out of the frame.
You need to cut the head off the lag screw so you can add a washer and nut to that end. By tightening the nut, the blade is tensioned.
At the other end of the frame is a carriage bolt that does not need to move. After I drilled the hole in the arm for the carriage bolt, I squared up the top of the hole so the carriage bolt can drop down into it, locking it in place.
At this point, you have a workable saw that will be murder on your hands.
Now comes the fun part: shaping the arms and stretchers to make the saw more comfortable to use and easier on the eyes.