Joinery
Wood and metal joints that go together square and stay that way. Bridles, hinges, tube corners, weld order.
Wood Joinery
2 rules
TWCDesign (@takuwoodcraft)Doweled bridle corner
Cut a through bridle at the corner: an open slot in the rail and a centre tenon on the leg, each a third of the stock width. Glue it, then drive glued dowels through it from two perpendicular faces, down through the slot cheeks and in through the side. Pinned both ways, it can't rack or pull apart.
Wooden knuckle hinge
Cut interleaving knuckles one router-bit width each, so one leaf's knuckles fill the other's slots. Round the knuckle ends to a full radius, tape the two leaves together meshed, and drill one pin hole through every knuckle in a single pass. A brass or copper pin about a third of the stock thickness finishes it.
Metal & Tube Joinery
4 rules
Craft Hacks StudioNotch-and-fold tube corner
To bend square tube to 90° without a bender, cut a 90° V-notch through three walls at the bend line, stop at the inside face of the fourth wall, and fold until the notch closes. The uncut wall becomes the hinge on the outside corner. Split the 90° across several smaller notches for a rounded corner.
WeldermanThree-way angle iron corner
For a three-way angle iron corner, lay all three pieces in their final positions with the ends overlapping, then scribe each miter line in place with a 45° square, from where the pieces cross out to the edge. Hash-mark the waste side of every line before anything moves, then cut to the lines.
Craft Hacks StudioSlit-and-fold rail cap
For a rail-to-post corner in the same size square tube, cut across the rail's side walls one post width from its end, leaving the top wall whole. Free and fold the bottom wall of that end section out of the way, then tap the end down over the post so its top wall caps it.
Weld sequence for a square corner
Tacks alone won't keep a mitered tube corner square; weld sequence does. After tacking, weld the outside corner first, work the remaining seams from the inside out, and run the fillet last. Let the corner cool completely, then check it with a square before you trust it.