What order should I assemble a woodworking project in?
Sub-assemblies before the whole, glue-ups you can still reach into, sanding before you box yourself in, and the dry run that tells you whether the plan works.
- Difficulty
- beginner
- Time
- 15 min
- Read
- 3 min
Short answer
Break the piece into sub-assemblies that can each be glued and checked square on their own, then join those. Do all the work that is hard to reach later — sanding, finishing insides, fitting hardware in tight corners — before the part that closes the piece up. Dry run every glue-up fully, timed, before any glue comes out.
Most disastrous glue-ups are planning failures rather than skill failures. A carcass with twelve joints, all needing glue at once, exceeds the open time of ordinary PVA and exceeds most people's number of hands. Deciding the order in advance turns one impossible operation into three easy ones.
Step by step
- Divide the piece into sub-assemblies.A table becomes two leg-and-rail frames, then those two joined by the long rails, then the top. A cabinet becomes a carcass, a face frame, a back, a door and drawers. Each sub-assembly is glued, clamped and checked square by itself.
- Dry run each glue-up completely and time it.Clamps set to roughly the right opening, cauls cut, blocks ready, everything within reach. If the dry run takes longer than the glue's open time, split it further or use a slow-setting glue.
- Do the finishing that will be unreachable later.Sand and often finish the insides of a carcass, the inner faces of a frame, and the back of a panel before assembly. Sanding into an internal corner after glue-up is slow and never as good.
- Mask off the glue surfaces if you pre-finish.Glue does not stick to finish. Tape over the tenons, the joint faces and the housings before applying anything.
- Fit hardware trial-wise before final assembly.Drill for hinges, catches and runners while the parts are flat on the bench and accessible. Take them off for finishing and refit at the end.
- Assemble so that each stage can be checked and corrected.Square each sub-assembly on a flat surface with diagonals before the glue grabs. An error caught at the frame stage costs a clamp adjustment; the same error found at final assembly costs the piece.
- Leave the closing component until last.The back panel, the top, the face frame — whichever component encloses the piece — goes on after everything inside it is done.
- Fit doors and drawers to the finished carcass, not to the drawing.The carcass as built is never exactly the carcass as drawn. Measure the actual openings after glue-up.
- Finish the outside last, after final levelling.Any planing, scraping or sanding to level joints has to happen before finish, and it always throws up a spot you missed.
Tips
- Number and mark every joint as you cut it. Parts that fit their partner and nothing else are extremely easy to mix up an hour later.
- Keep a written build order taped to the wall for anything with more than about six components. It sounds excessive and it prevents the one mistake that cannot be undone.
- Have a damp cloth, a chisel and a bin bag ready before the glue comes out, not after.
Common mistakes
- Gluing an entire carcass in one operation — The first joints are past their open time before the last clamp goes on, and there is no chance to check square. Sub-assemblies fix this completely.
- Leaving internal sanding until after assembly — Internal corners cannot be sanded properly with a machine or a flat block, and the result is a visible difference in surface quality inside the piece.
- Finishing before final levelling — Any joint that needs planing or scraping flush cuts through the finish, and patching finish is far harder than applying it once.
Questions people ask
Should I finish before or after assembly?
Pre-finish anything that will be hard to reach, and mask the glue surfaces. Finish the outside after final assembly and levelling. Most good work uses both at different stages rather than choosing one.
How many clamps do I need?
More than you think, and the dry run tells you the number. A useful rule is to have every clamp you will need already open to roughly the right size and within reach before any glue is spread.