A jig is how a small shop does what a big one does. Say what you're trying to cut and work it through: which jig does it, whether it's worth building, and every part sized from numbers you measure off your own machine. The math is shown, and the test at the end is pass or fail.
Craft intelligence, written down.
A machine makes one cut well. A jig holds the work, or the tool, so the machine makes your cut well, and then makes it again, and again, the same. Every jig that's worth the plywood buys one of three things. If it buys none of them, it's shop clutter with a name.
Six rails that match. Forty tenons the same length. A square cut on Tuesday that's still square in March. The jig carries the setting so you don't have to find it twice.
Your hands stay where they belong because the jig holds the part. A badly sized jig is a safety problem before it is a precision problem, which is why this page sizes before it draws.
Cuts the machine can't reach on its own: a taper, a dovetail in a long board, a curve that has to match a pattern. The jig turns the tool you have into the one you'd need.
A hundred-dollar router on a carriage cuts what a machine costing thousands cuts. That's the whole argument for jigs, and it's why the small shop never had to apologise.Hewn, The Grammar of Jigs, 2026
There's a reason jigs are the one piece of woodworking Hewn can check its own work on. You can't grade taste. You can grade square. A sled either passes the five-cut test or it doesn't; a tenon jig either makes a tenon that fits or it doesn't. That makes a jig the only woodworking output with a yes/no test, and the test is written into every one this page sizes.
Jigs look like a thousand different things and are really seven. Each family exists to answer one question about the cut, and the question is how Hewn tells which one you need. Say what you're trying to do and the verb in your sentence points at the family.
Straight-edge guides, router bases, dovetail guides. The tool rides something true.
Crosscut sleds, miter sleds, taper sleds. The work rides a carriage past the blade.
Patterns for curves, hinge mortises, inlays. One true shape, copied by a bearing.
Stop blocks, auxiliary fences, length stops. The dimension lives in the jig, not your tape.
Clamping and assembly fixtures, glue-up cauls. The part can't move, so the cut can't drift.
Story sticks, marking gauges, centre finders. A number kept as a thing, not a reading.
Bending forms, laminating forms, steam-bend jigs. The wood takes the jig's shape and keeps it.
You don't need to be. Describe the cut in plain words under Name the jig and the page says which family it heard, and why.
Jigs come in three tiers, and only the first one can be copied. The crosscut sled in a magazine was built for the author's table, the author's miter slot, the author's blade height. Build it from the drawing and it binds, rattles, or stops short. This page sizes the second and third tiers to the shop in front of you.
Works in any shop as drawn: a push stick, a bench hook, a marking gauge. The books have these right. Build them from the book.
Copy itSized to one machine: a crosscut sled, a router table fence, a tenon jig. Every dimension hangs off a measurement of your saw, and the book can't know it.
Sized hereBuilt for one part in one project: the curve of this chair's back rail, the taper of this table's leg. There is no book. The jig is the product of your layout.
NextHewn doesn't start from a jig and look for a reason. It starts from your problem, your shop and the stakes, and it's allowed to say the job isn't worth a jig. When it is, every part gets sized from a number you measured, the formula sits beside the number, and the build ends in a test that says yes or no.
"Cut six identical curved rails" is a copy-a-curve problem: the Template family. The page also names what people reach for first, and why it fails.
On this pageHow many parts, what tolerance actually matters, and how long the jig takes against doing it by hand. For one part the honest answer is usually no jig.
On this pageSlot width, slot to blade, table depth: numbers you take off the machine that exists, not a default. Every part is a formula of those numbers, and the formula is shown.
The crosscut sled, todayThe build steps, then the test that grades the jig: five cuts, an error per inch, a limit. Fails? The step says what to shim and whether you can undo it.
The crosscut sled, todayWhat you're making, what you own to make it with, and how much a bad cut costs you. The same three things a good shop teacher asks before answering.
A cut list with each part's formula, the layout mark, the steps in order, and the test. Not a plan copied from anywhere: a jig worked out for your numbers.
Square is measurable. Every sized jig ends with the measurement, the limit, what failing looks like, and what to do about it. If it can't be tested, it isn't finished.
Say it the way you'd say it across the bench: the cut, the count, the part. The page names the family it heard, the jigs that fit, the wrong answers, and whether it's worth building one. Nothing is sent anywhere; the answer is drawn on this page.
You are trying to cut a joint the same every time.
That points at the Template/Pattern family: the question it answers is, what holds the true shape?
How many parts is this: one, or a batch? The quantity decides whether a jig pays back. What tolerance actually matters for this job? Then compare: Hinge-Mortise Template is about 30 minutes to build, against doing it by hand once per part. A jig has to buy repeatability, safety or access; if it buys none of those for you, skip it.
Every jig named here is a draft entry: written down, not yet through its outside check. The test under each one is how you would know it worked.
The crosscut sled is the first jig this page sizes, because it's the one every table saw shop needs and the one every drawing gets wrong for your saw. Seven of the numbers come off your machine and your work; three are choices. The grey numbers in the boxes are a common cabinet saw, so you can see the shape before you fetch the calipers; type your own over them. Any box you leave blank is sized from the sample, and the answer will say which. The runners are the whole game: they're cut to your slot width less a few thousandths of play, and that's the number no book can know. The fence has to stand above the blade, and the page won't draw one that doesn't.
The second jig sized here is the taper jig, for legs that narrow to the foot: size a taper jig to your leg. Two widths and a start line, and the jig is set by the first leg you mark.
What's true about this page today. It names jigs from a written-out table of problems and families, not from guesswork, and it says so when it can't tell. It sizes two jigs so far, the crosscut sled here and the taper jig on its own page; the others are named but not yet sized, and every one of them is a draft entry still waiting on its outside check. The formulas are shown so you can check them; the five-cut test is how you check the sled, and the page does that arithmetic too. Nothing here is copied from a plan or a book, and nothing you type is kept.