A photograph is not a drawing
A photograph carries shape, colour and proportion. It does not carry a single dimension that can be manufactured. When a purchase order is a picture plus a price, every number the factory needs gets chosen by the factory, and the choices are invisible until the goods land. The usual outcome is a chair at 460 mm seat height instead of 450, a table at 760 instead of 750, and a set that is 10 mm out at every contact point, which is exactly enough to be uncomfortable and not enough to be obviously wrong in a photograph.
The cost of that gap is not the price difference. It is four to six weeks of remaking, a second sea freight, or an air freight bill on 40 chairs that can run 3 to 4 times the ocean cost, plus a restaurant opening date that does not move. A drawing pack that takes a buyer half a day to assemble removes that entire category of risk, and it is the same document the factory needs anyway to quote accurately rather than defensively.
The five dimensions that get left off
Seat height, first, and it is the one that ends in a callback. 450 mm to the top of the compressed seat is the number for a 750 mm table; the compression matters, because a 40 mm cushion that compresses 10 mm under a 75 kg guest is a 440 mm chair on paper and a 450 mm chair in use. Write both the uncompressed and the compressed figure, and write the load you compressed it at.
Seat depth, 450 to 480 mm for a dining chair, measured from the front edge to the back frame at seat level, not to the backrest face. Then back height above the floor, 850 to 900 mm for a dining chair, and the angle — 100 to 105 degrees from the seat plane is comfortable for a two hour meal and 95 is not. Fourth, knee clearance under the apron or the table frame, minimum 300 mm from the floor to the underside of the apron across the full seating width, and 620 mm between the legs at the knee position. Fifth, the overhang: 25 to 30 mm per side on a fixed table, and 20 mm on a pedestal, because past 30 mm a guest who leans on the edge tips a light base.
The relationship between them is the actual specification. Table height minus seat height should land between 250 and 300 mm, and the number that matters to the guest is 270 to 280. If a buyer changes the table from 750 to 760 because the top is 40 mm thick instead of 30, the chair does not need to change, but the gap does, and nobody notices until the chairs are already on the water.
Frame and joint callouts
State the species, not the colour. Oak and ash machine differently, move differently and take finish differently, and a drawing that only says natural wood will be built in whatever the factory has on the rack. Then the section sizes: a 38 by 38 mm leg for a timber dining chair is the minimum for a commercial chair, 32 mm is domestic, and the difference in a room doing 6 turns a day is a two year life against a six year life.
Joint detail is three lines on the drawing: mortise width and depth, tenon length, and the fastening that backs it up. An 8 mm mortise at 35 mm depth with a 30 mm tenon and a glued corner block is a commercial joint; a 6 mm mortise at 25 mm with no block is a decorative one. Screws, when they are used, want a gauge and a length, not a word: a 4 by 40 mm countersunk screw into a pilot hole at 80 percent of the shank diameter, two per joint, is a buildable instruction.
Add the parts that never appear on a rendering but always appear in a warranty claim: the glide or foot, its material and its fixing, and the floor protection under it. A nylon glide on a 12 mm stem is a different product from a felt pad, and a restaurant with a timber floor will care about which one was specified long after the drawing is filed. This is the level of detail that separates a restaurant furniture specification from a mood board, and it is the reason we ask for a section drawing rather than a front elevation alone.
Upholstery: foam, fabric and deck
Foam is specified by density and by thickness, and both numbers are needed. A seat at 35 kg/m³ and 60 mm thick holds its shape through 6 turns a day for five to seven years; 25 kg/m³ collapses to the deck in 18 to 24 months and takes the fabric with it, because a crease that forms over a collapsed seat is a tear within a year. Backs can run lighter, 25 kg/m³ at 40 mm, because they carry pressure rather than load.
The seat deck matters as much as the foam. 12 mm plywood with a 40 mm crown and webbing underneath stops the foam from being punched through at the front edge, which is where every chair fails first. Staple spacing at 40 to 50 mm around the deck edge, with the fabric pulled and not stretched, is the difference between a seat that stays flat and one that ripples along the front rail in the first summer.
Fabric needs three numbers: composition, abrasion cycles and light fastness. 40,000 Martindale cycles is the working minimum for a dining room, 25,000 is domestic, and a room with 300 covers a day wants 60,000 to 80,000. Light fastness at 6 or better on the blue wool scale, because a chair by a window fades on one side and the room looks uneven by year two. Send the fabric reference with the drawing, not the colour name — the word taupe covers about 400 different fabrics.
Finish, colour and the approval sample
Name the finish chemistry and the sheen. A two-pack polyurethane at 25 to 30 percent sheen is the right answer for a commercial dining room: it resists alcohol spills and cleaning agents, and it can be repaired locally. Nitrocellulose looks warmer and marks at the first hot plate. Powder coating on steel wants a film thickness in microns, 60 to 80, and a colour reference, not a photograph taken under a different lamp.
Colour needs a physical reference or a code. A RAL number for painted steel, a Pantone or a stained sample board for timber, and a signed approval sample in the buyer's hand before the batch starts. Stain lots vary: two batches of the same stain on the same species will differ by 1 to 2 on the delta-E scale, which is visible across a 30 chair room if the second batch is bought six months later. Note the lot on the drawing so the replacement order can be matched.
The last line on this section is the touch-up instruction. A restaurant will damage the finish inside the first month, at the chair back and at the table edge, and a 50 ml bottle of the matching lacquer with a stated repair method turns a 90 dollar chair replacement into a five minute job. It is the cheapest line in the whole pack and it is almost never written.
Tolerance, glides, packing and the container
Write the tolerance. Plus or minus 2 mm on any overall dimension, plus or minus 1 mm on a joint gap, and 1 mm maximum difference in leg length across a set of four, measured on a flat plate. Without a stated tolerance, 4 mm becomes close enough and a table that rocks becomes normal. With it, the factory has a number to inspect against and the buyer has grounds to reject, which is the only reason to write it down.
Packing is part of the drawing because it decides the landed cost. Chair cartons at 5-ply with a 20 mm foam wrap and two chairs per carton, table tops packed separately from bases with corner protection and a 3 mm hardboard facing, and a loading plan that states how many sets fit a 40 foot high cube. A room of 60 covers in restaurant table and chair sets is roughly 20 four-tops; the difference between 2 and 3 chairs per carton is 8 to 12 cubic metres, and that is a real number on the freight invoice.
Hardware goes on the list too: the bolts that fix a top to a base, the spanner that fits them, and a spare of each. A table that arrives without its fixing kit is a table that sits in the corridor on opening night, and a bag of 40 bolts costs less than the phone call.
The drawing pack, in order
One page per item, and in this order: a dimensioned front elevation, a side elevation, a plan, and a section through the joint that carries the load. Then the bill of materials with species, section sizes and quantities, the upholstery schedule with foam densities and fabric references, the finish schedule with chemistry, sheen and colour code, the tolerance block, and the packing note. Attach the approval sample photograph with a date, and the signed sign-off sheet.
Ten fields most packs still miss, in one list: compressed seat height under load, knee clearance at the apron, overhang per side, glide type and fixing, foam density per component, fabric abrasion and light fastness, finish sheen in percent, tolerance per dimension class, carton configuration and units per container, and the spare parts allowance. Every one of them has produced a claim in a project we have seen, and every one costs a line of text to close.
When the pack is complete, the floor plan and the drawing should agree. That is when restaurant tables for your floor plan and restaurant seating to your floor plan stop being catalogue browsing and become a quantity take-off: 20 four-tops at 700 mm square, 12 two-tops at 700 by 700, 8 armchairs at the window run, and a stack height for the chairs that get cleared for service. If a four-top has to be cleared and stacked for events, square timber table with stackable metal chairs is the kind of set the drawing has to describe down to the stack height and the contact point between frames, because that contact point is where the finish wears through in year two.
The same discipline applies to anything custom restaurant furniture covers, which in practice is most of a restaurant fit-out: non-standard table heights, banquettes built to a wall that is 40 mm out of square, and chairs sized to a room rather than to a catalogue page. Send the plan, the elevations and the sample references, and the pack that comes back is a quotation you can compare line by line instead of a price for a photograph. If you would rather start from your own drawing, send your floor plan and we will mark it up with the fields above before quoting.