What is PCD in a flange?
PCD means pitch circle diameter. It is the diameter of the imaginary circle that passes through the centre of every bolt hole in the flange.
FLANGE BUYER GUIDE
MS Flange PCD, OD, Bore and Drawing Requirement
Share these drawing details to get a practical quotation for MS Flanges, Mild Steel Slip-On Flanges and plate flange blanks from Regal Profile Mumbai.
PCD Guide
What PCD means in MS flange drawings
PCD is the bolt-hole circle size. If the PCD, hole count or bore is wrong, the flange may not match the pipe, pump, valve or fabrication fitment. Send the drawing or sample photo whenever possible.
| PCD | Pitch circle diameter The circle on which bolt-hole centers sit. This is one of the most important flange drawing details. |
|---|---|
| Hole count | Total number of bolt holes Mention 4, 6, 8, 12 or the exact count shown on the drawing. |
| Hole size | Diameter of each bolt hole If holes are slotted, mention slot length, width and direction. |
| Bore / ID | Inner opening or pipe clearance Mention machining allowance if the bore will be finished later on lathe. |
| OD | Outer diameter Send final OD or rough blank OD if machining allowance is needed. |
PCD geometry tool
Check equal bolt-hole spacing before sending the drawing
Enter the PCD, number of holes and hole diameter to calculate angular spacing and adjacent centre distance. The approved project drawing remains the production reference.
Drawing check
PCD bolt-hole geometry calculator
- PCD radius
- 100 mm
- Angular spacing
- 45.00 degrees
- Adjacent centres
- 76.54 mm
- Approx. edge gap
- 58.54 mm
Geometry aid only. It does not select a flange standard or pressure class. A red overlap warning means the entered hole diameter is larger than the calculated gap between adjacent centres. Use the approved project drawing for production dimensions.
Details Needed for MS Flanges
For faster MS Flange, slip-on flange or MS ring blank quotation, send a drawing or a clear photo with OD, bore, PCD, hole count, hole size, thickness and quantity. These details help avoid rework and help the workshop check material, cutting, drilling and machining feasibility properly.
| OD | Outer diameter of the flange |
|---|---|
| ID / Bore | Inner bore size or center opening |
| Flange Type | Plate flange, slip-on flange blank, blind flange-style plate or MS ring blank |
| PCD | Pitch circle diameter for bolt holes |
| Hole Details | Number of holes and hole diameter |
| Thickness | Flange thickness required for the job, with heavy MS plate support up to 200mm depending on size and stock |
| Standard | Project requirement such as IS 2062, ANSI, ASME or DIN if specified by the buyer |
| Quantity | Total pieces and delivery urgency |
| Application | Piping, fabrication, machinery, tank or structural use |
Buyer questions
PCD questions buyers ask before ordering
Is flange PCD the same as flange OD?
No. OD is the outside diameter of the flange, while PCD controls the circle on which the bolt-hole centres are positioned. Both dimensions must be shown separately.
What details are needed with flange PCD?
Send PCD, hole count, hole diameter, OD, bore, thickness, flange type and quantity. Mention slots, orientation and machining allowance where applicable.
Can PCD be checked from an old flange sample?
An old sample can help initial checking, but production should follow an approved drawing or confirmed size list so hole centres, bore and OD are not based on an uncertain measurement.
Reference this guide
Stable source for buyer and engineering notes
Publications, procurement teams and fabricators may cite this page with a link to the original guide. Technical suitability must still be checked against the approved project drawing.
Reviewed 1 August 2026