B2B & Suppliers
NPT vs BSP Thread: They Screw Together, Then They Leak
NPT vs BSP thread runs 14 TPI in both at 1/2 in, so it assembles and then leaks. TPI and major-diameter tables, plus an eight-field callout template.
Field Notes
Tips and guides for adding size annotations to your product images
Compliance
EI30 vs FD30: Four Markets, Four Fire Door Ratings
EI30 vs FD30 is not the same rating: EI covers integrity and insulation, FD covers integrity only. Four export markets, four systems, one decision tree.
Size & Fit
Aluminium Extrusion Slot Width: Why 2020 Is Not a Spec
Aluminium extrusion slot width is the number 2020 never tells you. Five ordering mistakes, the kg/m test, and the eight-field spec block that ends them.
B2B & Suppliers
Mesh Count vs Micron: Same 100 Mesh, 51 Microns Apart
Mesh count vs micron: mesh is a weave density, not an aperture. Two 100-mesh cloths can differ by 51 microns and both be honestly labelled.
Size & Fit
Drawer Slide Clearance: Lock 4 Numbers Before You Cut
Drawer slide clearance is 12.7 mm per side for side-mount and a material-dependent deduction for undermount. Here is the order to lock the numbers in.
Size & Fit
Cabinet Hinge Boring Dimensions: Five Numbers, Not One
Cabinet hinge boring dimensions are five numbers, not one: 35 mm cup, 13 mm depth, drilling distance, fixing pattern and cup position along the door.
Compliance
STC vs Rw: Why Your 45 dB Window Gets Graded at 39
STC vs Rw sound ratings differ by 1-2 points, but Rw+Ctr can cut 6 dB. What each index measures, which market grades on which, and how to write the acoustic line.
Size & Fit
Full Overlay vs Half Overlay: Two Answers, 9.5 mm Apart
Full overlay vs half overlay means different geometry on face-frame and frameless cabinets: the door-size math, the reveal, and what to ask before cutting.
B2B & Suppliers
Shore A vs Shore D: Why 'Shore 70' Is Not a Spec
Shore A vs Shore D hardness are two instruments, not two precisions: why 'Shore 70' is not a spec, why no conversion exists, and how to write a callout that holds.
Compliance
Stair Riser and Tread Dimensions: The 3/8-Inch Rule
Stair riser and tread dimensions are capped by two numbers per market, and failed by a third: no riser may differ from another by more than 3/8 inch. Limits for four markets.
B2B & Suppliers
Ra vs Rz: Same Number, Two Completely Different Surfaces
Ra vs Rz measure different things — two parts can share an Ra and only one will seal. What each parameter sees, why no conversion factor works, and what ISO 21920 changed.
Size & Fit
What Size Dining Table Seats 8? Run the Clearance Math
What size dining table seats 8 takes three numbers, not one: edge length per person, table width, and the clearance behind the chairs. With the full sizing table.