Custom Machined Flanges
Resolute Precision Manufacturing produces custom machined flanges to your drawing: turned, faced, bored, and drilled to your specifications in steel, stainless, aluminum, and brass. Whether you need a simple pipe flange with a drilled bolt circle or a complex weld neck flange with precision bore and face tolerances, our custom flange machining services deliver it directly to your team, with 24-hour quote response and ISO 9001 controlled quality. Request a QuoteTurning and Milling Combined for Custom Flange Machining
A precision flange requires both turning operations (OD, bore, and face) and milling or drilling operations (bolt holes, slots, and machined pockets). At Resolute Precision, custom machined flanges are produced on CNC turning centers with live tooling that complete the turned OD, bore, and face in the same operation as the drilled bolt hole pattern and any milled features.
For larger flanges that exceed our bar-fed turning diameter, chucked turning followed by milling on our vertical machining centers produces flanges up to 25.5 inches in diameter, with all features referenced from a single common datum.
Critical Flange Dimensions and Tolerances
The dimensions that matter most on a precision flange are:
- Face flatness and perpendicularity to the bore axis
- Bore diameter and finish, which must match the mating pipe or fitting
- Bolt hole circle diameter and angular spacing
- Overall thickness
Our custom flange machining services hold these dimensions to drawing specifications, with CMM-verified inspection on first articles and spot checks throughout production runs.
Flange Applications From RPM
Custom machined flanges from Resolute Precision are used across a broad range of fluid, mechanical, and structural connection applications:
- Pipe flanges: ASME B16.5 weld neck, slip-on, socket weld, and blind flanges in carbon and stainless steel
- Hydraulic and pneumatic flanges: SAE 4-bolt and 2-bolt split flanges for high-pressure connections
- Shaft flanges and couplings: precision turned flanges for shaft-to-shaft and shaft-to-housing connections
- Instrument flanges: stainless flanges for pressure, temperature, and flow instrument connections
- Industrial machinery mounting flanges: custom flanges for motor, gearbox, and actuator mounting
- Marine hardware flanges: brass and stainless flanges for through-hull and sea-cock connections
Specifications
| Turning Capacity | OD up to 25.5″ diameter; bore sizes from small-bore to near-OD |
| Bolt Hole Patterns | Drilled with live tooling (smaller flanges) or machined on vertical mills (larger flanges) |
| Face Flatness | Turned and faced in the same setup; flatness to drawing specifications |
| Bore Finish | Bored or reamed to the specified diameter and surface finish |
| Standards | ASME B16.5, ASME B16.47, DIN, JIS, or customer-proprietary drawings |
| Metals | Carbon steel (A105, 1018), stainless steel (304/316/F316L), aluminum (6061), brass |
| Tolerance | OD/bore: ±0.001″ standard; flatness: 0.001″ per inch; bolt circle: ±0.002″ standard |
| Volume | Prototype to production |
| Certifications | ISO 9001:2015 |
Frequently Asked Questions
Can RPM produce ASME standard flanges?
Yes. We produce flanges to ASME B16.5, B16.47, B16.48, and other applicable standards. We work from your drawing that references the standard we machine to the dimensions and tolerances that drawing calls for.
What is the largest flange diameter RPM can produce?
Our turning centers handle chucked workpieces up to 25.5″ in diameter. For larger flanges, we can machine the critical ID, OD, and face features on a turning center and complete the bolt hole pattern on our vertical machining centers.
Can RPM supply flanges with material traceability?
Yes. We source materials with mill certifications and can provide certified material test reports (CMTR) with the delivery. For pressure-containing applications or regulated industries, material traceability documentation is available on request.
Does RPM offer flanges with surface treatment?
Yes. Through our outside coating and processing services, we coordinate passivation of stainless flanges, zinc or nickel plating of carbon steel flanges, and anodizing of aluminum flanges delivering fully finished parts from a single purchase order.