How to Read a Door Hardware Drawing: P, Ø, W.L, Cutouts and Brackets

Updated 2026-11-09 · RAYEN 雷茵

Why learn to read the drawing?

A drawing is the specification's first draft. Every figure on it is a promise about where a hole will be. A buyer who reads it correctly can check a part against a door before ordering a container. A buyer who misreads one mark drills every hole in the wrong place. These are the marks you will see on ours.

P: the distance between fixings

P is the centre distance: from the centre of one fixing to the centre of the next. It is the figure you set out on the wall or the door.

Take PRE_G400, a towel bar. It is 500mm overall, with P=450mm. The holes are 450mm apart, not 500mm. Marking the overall length puts both holes in the wrong place.

Some parts have more than one P. PRE150 lists P=75mm twice, for two pairs of fixings. A wall plate may give P across and P up the plate, as on OASHB3000: P=40mm across and P=110mm + P=60mm up.

Ø: a diameter

Ø marks a round size: a tube, a rose or a hole. HB2102 has a Ø32mm tube on Ø80mm roses. Check which one a Ø refers to by following its leader line. A tube diameter and a rose diameter on the same drawing are easy to swap in a hurry.

W.L: the wall line

W.L is the face of the finished wall. A dimension that runs to it tells you how far the part stands off the wall, or how far it reaches from the wall. On a grab bar or a robe hook, that is the clearance a person has to live with. Measure your own wall to the finished face, tile included, to compare.

The cutout

A part that sits in a wall or a door shows the opening you must cut. On our drawings it is marked with the Chinese word for opening, kai kong, next to its figure. OAS_PTH01 has a 345 × 345mm face plate over a 327 × 316mm cutout. The plate is larger than the cutout so it covers the edge. Always cut to the cutout, never to the plate. See recessed bathroom cutouts.

Figures in brackets

A figure in brackets has one of two meanings, and the note beside it says which.

• A second version. On PRE150, the door thickness reads 40mm with a 45mm version available, and the cutout is 42 × 174mm, or 46mm wide for 45mm doors. The bracketed figures belong to the 45mm door.
• A reference size, given for information and not to be made to. Ask us if you are not sure which you are reading.

Ranges and inches

A range such as 35-50mm on AL-114 is the door thickness the part is made for. Your door must fall inside it. Some parts are sized in inches: D3762 SS comes in lengths from 6” to 24” and is 1” wide. Do not convert in your head on an order. Write the size as the drawing gives it.

What to do when a figure is unclear

Ask. A figure you cannot place on the part is a figure that can go wrong. Every figure in our specification tables comes from the factory drawing or a measurement, so we can tell you what each one measures. If two figures on a drawing seem to disagree, send us the drawing with the question marked, and we answer before you order.

Next step

Send the drawing you are reading, or your own, to [email protected] with the figures you want checked. Or WhatsApp the factory owner; the number is on the contact page. We mark up the answer on the drawing.