CNC Machined Flanges
Flanges join two components through a bolted, often sealed interface — so bolt-hole pattern accuracy and sealing-face flatness are what matter. We machine custom pipe, mounting, and adapter flanges in steel, stainless, and aluminum to your pattern and standard.
What is a CNC machined flanges?
A flange is a flat, usually round collar that connects pipes, shafts, valves, or equipment through a ring of bolt holes and a sealing face. CNC machining produces custom flanges, non-standard bolt patterns, and adapter flanges that mate two different standards — with the bolt-circle accuracy and face flatness that a sealed, leak-free joint requires. The critical features are the bolt-hole position (on the bolt circle) and the sealing-face flatness and finish.
Common materials
The standard for structural and pipe flanges carrying load and pressure.
For corrosion resistance in fluid, marine, food, and chemical service.
Lightweight mounting and adapter flanges where load is moderate.
Typical tolerance
±0.05 mm (bolt circle tighter)
Bolt-hole position on the bolt circle and sealing-face flatness are the critical features — held tight so the flange bolts up and seals to its mating part.
How we machine them
Machines the round body, bore, raised face, and outer diameter.
Drills the bolt-hole pattern accurately on the bolt circle.
Produces the flat, specified-finish sealing face.
Design tips that lower cost
Reference bolt holes to the bolt circle
Position the bolt holes with their location on the bolt-circle diameter and angular spacing. This is the feature that lets the flange bolt up to its mating part — call it out clearly.
Specify sealing-face flatness and finish
A flange that isn't flat won't seal. State the flatness and the surface finish (or the standard, e.g. a raised-face serrated finish) on the sealing face.
Match an existing flange standard where possible
If the flange mates to a standard component, machine it to that standard (ANSI/DIN/JIS) so it bolts up and seals with off-the-shelf gaskets and fasteners.
Call out the mating bore fit
Where the flange registers onto a pipe or shaft, specify the bore fit (e.g. H7) so the assembly locates correctly.
Industries we machine flanges for
Flanges — frequently asked
Can you machine flanges to ANSI, DIN, or JIS standards?
Yes — give us the standard and class (or a drawing) and we machine the bolt pattern, face, and bore to match so the flange mates to standard components.
Can you make adapter flanges between two standards?
Yes. Adapter flanges with a different bolt pattern on each face are a common custom-machined part — share both interfaces and we'll machine the adapter.
What tolerance do you hold on the bolt-hole pattern?
Bolt-hole positions are held tight (typically ±0.05 mm or better) so the flange bolts up without binding to its mating part.
Need flanges machined?
Upload your drawing — our engineers review it for DFM and send a real quote within 24 hours. No minimum order.
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