Valve Seat Cone with 90% Blue Checked Contact Band and 0.01mm Seat Runout, Air Tested at Working Pressure
Valve Seat Cone Turning
,Seat Contact Blue Check
,Cone Angle Seat 0.01mm
A conical seat seals on a narrow contact band, not on a drawing dimension. Every seat is turned with a profiling insert, lapped where specified, blue checked against a matched gauge, and air tested at working pressure before packing.
- Contact pattern90% or better on blue check
- Cone angle±0.02°, optical and profile measured
- Order size1 piece, prototype in 3–7 working days
- MaterialsSS316L / 304 / 303, brass C36000
- Seat finishLapped to Ra 0.4 µm
- Track recordExporting since 2008, ISO 9001:2015
A conical seat seals on a narrow band where the cone meets its mating part. The drawing gives a cone angle, an opening diameter and a depth — and a supplier can hit all three while still shipping seats that leak. What actually seals is the contact pattern: how much of the cone circumference touches, where the band sits along the cone, and how smooth that band is. A cone that is on angle but has a chatter ring around it will pass a diameter check and fail a leak test.
So the seat is finished in a way that produces a clean band, then verified the way the customer uses it. The cone is turned with a small nose radius at a controlled feed, lapped where the specification requires a fine band, checked with blue on a matched gauge to confirm contact percentage and position, and air tested at working pressure before packing. Cone angle, seat runout and band width are recorded together — because a good angle with a band in the wrong place seals just as badly as a bad angle.
| Step | Operation | Control Point |
|---|---|---|
| 1 | Bar and certificate | SS316L, 304, 303 or brass bar, mill certificate traceable to heat number. |
| 2 | Rough turn body and recess | Outside diameter and the deep recess roughed with stock left inside, so the finishing pass is a light, stable cut. |
| 3 | Semi-finish bore and cone | Bore and cone brought close to size; the cone is cut with a profiling insert so the angle comes from the tool path, not from a form tool that wears. |
| 4 | Seat finishing | Cone finished with a small nose radius at low feed to give a continuous band without chatter; roughness checked on the band itself. |
| 5 | Lapping where specified | Seat lapped on a matched lap to widen the contact band and bring Ra to 0.4 µm; band position re-checked after lapping. |
| 6 | Threads and ports | Threads cut with relief and gauged; cross ports drilled and deburred from inside so no chip reaches the seat. |
| 7 | Blue check and cleaning | Contact pattern checked against a matched gauge; part cleaned and borescope inspected before any test. |
| 8 | Air test and pack | Leak test at working pressure with the record shipped; seats protected with caps, parts bagged individually. |
| Feature | Held To | Verified By |
|---|---|---|
| Cone angle | ±0.02° | Profile projector and optical comparator |
| Seat contact band | 90% or better, per drawing | Blue check on matched gauge |
| Seat runout to bore | 0.01 mm | CMM and indicator |
| Seat band roughness | Ra 0.4 µm (Ra 0.8 as-machined) | Roughness tester on the band |
| Seat opening diameter | ±0.01 mm | CMM |
| Seat depth from face | ±0.02 mm | Depth gauge and CMM |
| Bore diameter | ±0.01 mm | Bore gauge |
| Bore to OD concentricity | 0.01 mm | CMM |
| Thread | 6g / 6H, gauged 100% | Go / no-go gauges |
| Leak tightness | No bubble or decay at test pressure | Air or hydrostatic test with record |
- Material: SS316L for aggressive media, SS304 general, SS303 for fine finish, brass C36000 for potable water and instrumentation, 17-4PH for high pressure, PTFE and PEEK for chemically aggressive seats.
- Seat forms: 30°, 45° or 60° cone, radius seat, flat seat with relief, double seat, seat with a secondary sealing land.
- Body forms: straight cup body, deep recess cup, body with flange, body with hex or spanner flats, body with cross port, angled body.
- Finish: passivation per ASTM A967, electropolish for hygienic service, bead blast on non-sealing surfaces, as-machined seats.
- Size: body diameter 8 mm to 120 mm, seat diameter 2 mm to 80 mm, depth to 150 mm.
- Input: STEP, IGES, DXF, PDF drawing, or a sample valve body we measure and re-model.
A valve seat drawing carries the cone angle, the seat band width and the spring or actuator interface — together these describe how a system controls flow, which is confidential design intent rather than a commodity dimension. We sign a mutual NDA before any file is opened, in English or Chinese or on your own form, and return a countersigned copy before work starts.
Access is limited to the project engineer, the lathe programmer and the cell supervisor, with the file held in a restricted folder rather than the open shop network. The cell is camera free: no photographs for our catalogue or website, no customer part kept on display or reused as a sample, subcontracting only with your written approval, and at program close drawings, test records and inspection data are deleted or returned with written confirmation.
Dongguan Changxinda Precision Technology Co., Ltd has machined custom metal parts since 2008: 15+ years, 90 to 100 staff, 50–60% of output exported to North America and Europe, 200+ customers served, turnover in the RMB 10–20 million band. The plant runs CNC lathes, turn-mill combined centres with live tooling and sub-spindle, and 4-axis / 5-axis machining centres under an ISO 9001:2015 quality system, serving medical, robotics, automotive, aerospace, automation, laser, LED, lithium battery and precision instrument programs. Turning, lapping, passivation coordination and leak testing are handled in our own plant in Dongguan.
Seat and valve components from this plant ship into ten sectors. The list is what customers order, not a marketing wish-list.
| Industry | Typical Parts We Machine |
|---|---|
| Consumer electronics | Phone, tablet and laptop housings / heat spreaders / camera brackets / VR and AR headset structural parts / smart wearable enclosures |
| Automation and industrial equipment | Automation jigs and fixtures / module frames / linear guide blocks / motor mounts / sensor housings / conveyor line components |
| Semiconductor and vacuum | Vacuum chamber bodies / vacuum fittings / precision bases for semiconductor equipment / thermal and insulating parts / inspection tooling |
| Medical equipment | Surgical instrument bases / medical instrument housings / endoscope components / aesthetic device structural parts (medical grade aluminium and stainless) |
| Automotive | New energy motor housings / battery end plates / sensor brackets / lighting structural parts / retrofit components / hydraulic valve blocks |
| Aerospace and UAV | Aircraft structural parts / UAV frames / landing gear components / avionics instrument housings (lightweight precision parts) |
| Optics and photonics | Optical lens barrels / lens mounts / light source heat sinks / camera module brackets / inspection optical platforms |
| Telecom | 5G heat dissipation cavities / filter components / signal adapter structural parts / telecom equipment enclosures |
| Robotics | Robot arm joint parts / robot bases / reducer housings / AGV structural components |
| Instrumentation | Test equipment housings / precision gauge bases / flow meter components / laboratory equipment parts |
All ten sectors run through the same plant and the same ISO 9001:2015 inspection discipline — only the material, finish and documentation package change.
- Prototype: 4–7 working days after drawing approval, including lapping and air test.
- Small batch 10–100 pcs: 8–15 working days.
- Repeat orders: released from archived program, lap and tool list — seat angle and band position repeat to the same values.
- Capacity: 10,000 pieces per month across the plant.
- Visibility: a dated progress note with photos of your actual parts at cone turning, lapping and testing.
- Shipping: seats capped and protected, parts bagged individually, foam-lined export carton so a seat cannot be nicked in transit.
- Rush: lapping and test slots held weekly; tell us the deadline and we confirm before the order.
By blue checking the contact pattern against a matched gauge and then air or hydro testing at your working pressure, with the record shipped. A cone angle alone does not prove a seal; the contact band percentage and its position do.
A profiling insert, so the angle comes from the tool path rather than from a form tool that wears and drifts. That matters on 45° seats, where a worn form tool changes the band position without changing the angle reading.
Yes. Lapping is done on a matched lap and the band position is re-checked afterwards, because lapping widens the band and can move it if the lap is not guided.
The recess is flushed and borescope inspected before the test fixture goes on, and ports are plugged during finishing. A chip sitting on a seat gives a leak that looks like a geometry problem and wastes everyone's time.
One piece, no tooling charge. Price follows material, seat angle and band requirement, depth, thread and test specification; a written quotation normally returns within 24 hours.
Yes, routinely, and a countersigned copy comes back before work starts. Only the engineer, programmer and supervisor see the file, no photographs leave the cell, and nothing about your valve appears in our catalogue or website.
Attach the model or drawing with the quantity, the working media and pressure, the seat band requirement and the deadline. You will receive a quotation, a process route including lapping and testing, and a firm delivery date. NDA paperwork can be handled in the same exchange.
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