Precision Oil Sight Glasses &
Breather Vent Plugs

Grand Hardware Manufacturing Co., Ltd – Trusted OEM supplier of high-performance oil level indicators, fused sight windows, and breather vent plugs for industrial applications worldwide.

Explore Products Download Catalogue

Global Experience

Exported GrandMfg® Oil Sight Glass for over 20 years to clients across North America, Europe, and Asia.

OEM & ODM Support

Custom designs, drawings, and samples accepted. We bring your ideas to life with precision engineering.

Confidentiality Guaranteed

Your customized parts remain exclusive to you. No public listings or third-party sharing.

About Grand Hardware Mfg

Grand Hardware Manufacturing Co., Ltd, along with Yuhuan Yize Manufacturing Co., Ltd, is a professional OEM metal parts supplier with over two decades of experience in precision manufacturing.

We specialize in producing high-quality oil level sight glasses, fused sight windows, breather vent plugs, hydraulic adapters, oil drain plugs, and other critical industrial components.

Our expertise spans CNC machining, stamping, laser carving, and advanced surface treatments with tolerances as tight as ±0.01mm. We serve industries including automotive, heavy machinery, gearboxes, compressors, and hydraulic systems.

ISO-Compliant Manufacturing
Materials: Brass, Stainless Steel, Aluminum, Carbon Steel, Plastic
Surface Treatments: Zinc Plating, Anodizing, Nickel Coating
Custom OEM/ODM Projects Welcome

Our Product Range

High-performance oil sight glasses and related components for diverse industrial applications

Brass Oil Sight Glass

Durable NPT-threaded brass construction ideal for gear units, pumps, and compressors.

• Material: Brass
• Thread: NPT, BSP
• Sizes: 1/4" to 2"
• Application: Gearboxes, Blowers

Stainless Steel Oil Sight Glass

Corrosion-resistant 304 SS sight glass for harsh environments and process pumps.

• Material: SS304 / SS316
• Pressure Rated
• ANSI/ASME Compliant
• High Temp Resistant

Aluminum Oil Sight Glass

Lightweight option with anodized finish for reduced weight in mobile equipment.

• Material: Aluminum Alloy
• Lightweight Design
• Anodized Surface
• Ideal for Trucks & Buses

Carbon Steel Oil Sight Glass

High-strength solution for heavy-duty industrial machinery and hydraulic systems.

• Material: Carbon Steel
• Zinc Plated
• High Pressure Rating
• Robust Construction

Fused Sight Glass Window

Hermetically sealed fused quartz window for extreme temperature and pressure.

• Fused Quartz Glass
• Hermetic Seal
• High Temp & Pressure
• Leak-Proof Design

Breather Air Vent Plug

Prevents pressure buildup in enclosures with dust and moisture filtration.

• G3/8", NPT Options
• Filtration Mesh
• For Gearboxes & Motors
• Siemens Flender Compatible

Tubular Oil Level Indicator

Clear tubular gauge with red float ball for easy visual oil level monitoring.

• Brass Body
• Red Float Ball
• Direct Reading
• For Pumps & Blowers

Radiator Filler Neck & Cap

Precision-engineered coolant system components for automotive and industrial use.

• Brass or Steel
• Pressure Relief Valve
• Leak-Proof Seal
• Custom Threads Available

View Full Product Catalog

Why Choose GrandMfg®?

Engineered for reliability, precision, and long-term performance

Precision Engineering

Tolerances controlled to ±0.01mm using high-speed CNC and digital processing.

Custom OEM/ODM

We accept custom drawings, samples, and special design requests with confidentiality.

Multi-Material Expertise

Brass, stainless steel, aluminum, carbon steel, bronze, and plastic components.

Advanced Surface Treatments

Zinc plating, anodizing, nickel coating, and laser marking for durability.

Frequently Asked Questions

What materials are available for oil sight glasses?

We offer oil sight glasses in brass, stainless steel (304/316), aluminum alloy, carbon steel, and plastic. Custom material requests are welcome.

Can you produce custom designs?

Yes, OEM and ODM services are fully supported. Send us your drawings, samples, or specifications and we’ll manufacture exactly what you need with full confidentiality.

What thread types do you support?

We produce sight glasses with NPT, BSP, metric (M), and custom thread configurations. Common sizes range from 1/4” to 2”.

Do you offer surface treatments?

Yes, available treatments include zinc plating, zinc-nickel plating, anodizing, nickel coating, and laser engraving for branding or identification.

What industries do you serve?

Our products are used in gearboxes, compressors, pumps, blowers, hydraulic systems, automotive, heavy trucks, buses, and industrial machinery.

China Quality Suppliers fobcompany.info

Notice for Buyers: If you are a buyer, the above information is generated by AI collection and does not constitute any advice. If necessary, please visit the corresponding official website.

For Domain Owners: If you are the domain owner and do not want to be included by fobcompany.info, please contact [email protected] via your corporate email to cancel. We will cancel your inclusion within 3 business days.

如果您是域名所有者不想被fobcompany.info收录请用企业邮箱联系[email protected] 取消收录我们将在3个工作日取消您的收录

Service Request: If you are other domain and want to be included, please contact [email protected]

如果您是其他域名合作也请联系[email protected]

Precision Oil Sight Glasses & Breather Vent Plugs