The Six Values a Hardware Order Actually Needs

A model number is not an order. It names a family and a form; it does not say which of the variants inside that family fits the door in front of you. The gap between the two is where a week goes, because the questions are asked one at a time by email across an eight-hour time difference.

Six values close the gap: model, finish, backset, centre distance, handing, door thickness. Written in that order they read as one reference — 9001-SSS-60-72-L-45 — and every one of them is a fact about the opening rather than a preference. Nothing on that line is negotiable after the mortise is cut.

Model is the family. Finish is the code, not the word: SSS and PSS are both "stainless", they are a satin and a mirror, and they do not sit next to each other on the same floor. Where a US equivalent exists we publish it beside the code, because a schedule written to US32D and a factory reading SSS are describing the same part and should not have to discover that by correspondence.

Backset is the distance from the face of the door edge to the centre of the spindle, and it is set by the door, not by the lock. A 60mm backset lock in a door prepared for 45mm does not go in. Centre distance is the gap between the spindle and the cylinder, and it is what decides whether the handle and the key hole line up with the holes already drilled in the plate.

Handing is a letter — left, right or universal — and it is discussed in its own article because the two conventions in use disagree. Door thickness is the one people assume is standard and is not: our records carry ranges like 35–45mm adjustable and 35–50mm, because the spindle and the fixing screws have a working travel and a 60mm door is outside it.

What happens when a value is missing depends on which one. A missing finish delays a quotation. A missing backset delays a shipment, because it is not visible until the case is offered up to the door and by then the container has landed. That asymmetry is the argument for writing all six at enquiry rather than the ones that feel important.

Two of the six are frequently unknown at enquiry, and saying so is a valid answer. "Door thickness to be confirmed" is a line an export engineer can work with — it flags the risk and keeps the rest of the quotation moving. A blank is not the same thing: a blank gets filled in by whoever is in the most hurry.

Our guided selector asks four of the six and returns a published model with its specification rather than a category, so the reference can be pasted straight into a schedule. Where a figure is not published for a model, the specification table shows a dash rather than a plausible number — the dash is a question for us, and it is cheaper to ask it now than to answer it on site.