Manual Tightening Tools Wholesale Factory

BOSI Tools is a manual tightening tools manufacturer from China, offering a product range that includes screwdrivers, 9-piece multi-purpose screwdriver sets, 19-in-1 ratchet screwdrivers, double-handled rivet guns, and semi-circular caulking guns.

From chrome-molybdenum steel magnetic blades to chrome-vanadium steel precision bits, from labor-saving riveting to precise caulk application—BOSI provides efficient fastening solutions for electronic assembly, sheet metal fabrication, door and window installation, and general maintenance through solid material craftsmanship and comprehensive product configurations.

We offer one-on-one selection guidance and customized services. Inquiries by phone or online are welcome.

What Are Fastening Tools?

Fastening tools, also called manual tightening tools, is a general term for various manual and combination tools used for tightening and loosening screws and nuts, or for permanently joining two separate components through plastic deformation. BOSI fastening tools encompass four major categories: screwdrivers, ratchet screwdrivers, double-handled rivet guns, and semi-circular caulking guns.

Screwdrivers utilize a chrome-molybdenum steel blade paired with a strong magnetic bit to transfer manual rotational force to the screw recess, completing tightening or loosening actions. The Diamond series blades feature a mirror-polished bright chrome finish, enhancing durability by 30%. The 9-piece multi-purpose screwdriver set builds on this with expanded specification coverage, featuring interchangeable handles and blades.

The 19-in-1 ratchet screwdriver incorporates concealed storage and a dual-direction ratchet head tested for over 5,000 fatigue cycles; forward/reverse ratchet adjustment improves efficiency during repetitive fastening and removal.

The double-handled rivet gun employs a labor-saving lever structure to pull and break the rivet mandrel, causing the rivet body to expand and lock the workpiece, suitable for 3.2mm, 4.0mm, and 4.8mm iron and aluminum rivets.

The semi-circular caulking gun features a 1.0mm thick steel plate body and a high-strength die-cast aluminum alloy handle, advancing the cartridge piston via a central push rod to uniformly extrude sealant or glass adhesive.

Our Fastening Tools vs. Other Brands: Why Choose BOSI?

BOSI fastening tools are built around high-quality materials such as chrome-molybdenum steel and S2 alloy steel. Enhanced by heat treatment and strong magnetic design to improve operational efficiency, they establish a clear advantage over generic brands in blade durability, bit specification coverage, and operational comfort.

What Materials Can Be Processed?

BOSI fastening tools cover materials and scenarios across multiple fields, from electronics to construction:

Metal Sheets and Profiles

The Double-handled rivet gun can pull 3.2mm, 4.0mm, and 4.8mm aluminum or iron rivets, used for riveting and fastening thin metal sheets, fiberboard, leather, and plastic panels.

Suitable for assembling ventilation ducts, billboard frames, and luggage fittings.

Screws and Fasteners

The screwdriver series, with strong magnetic bits, can hold Φ3-8mm slotted, Phillips, and various specialty screws, compatible with appliance housings, computer cases, furniture hardware, and electrical wiring terminals.

Sealants and Glass Adhesive

The Semi-circular caulking gun works with standard cartridges; the central push rod offers excellent braking, and the powder-metallurgy propulsion disc is high-strength.

Suitable for door and window installation, sanitary sealing, and curtain wall weatherproof sealant application.

General Repair and Precision Disassembly/Assembly

The 19-in-1 ratchet screwdriver integrates PH1-PH3, T10-T25 Torx, U-type, Y-type, and other bits, capable of handling multi-recess screws in phones, laptops, precision instruments, and more.

How to Choose the Right Fastening Tools?

Selection is based primarily on the type of work. For daily screw fastening and removal, the Diamond series screwdrivers are the first choice; for specification flexibility, choose the 9-piece set.

For frequent fastening or work in tight spaces, use the ratchet screwdriver. For joining panels, use the rivet gun.

For applying sealant, choose the caulking gun—the thickness of the gun body and the material of the propulsion disc directly affect the uniformity of the bead dispensed by the nozzle.

Safety Precautions for Use

Screwdriver Use

The bit recess type must perfectly match the screw recess; a mismatch will strip the screw or fracture the bit.

For hot work, use insulated screwdrivers; standard screwdrivers must not be used on live circuits.

Do not use the blade as a pry bar or chisel to avoid bending or breakage.

Ratchet Screwdriver Adjustment

When adjusting the dual-direction ratchet, listen for the click to confirm the setting is engaged; never switch direction while turning.

When installing a bit, ensure it is fully inserted into the magnetic interface to prevent it from falling out and getting lost.

Rivet Gun Operation

The rivet specification must match the nosepiece; use the corresponding nosepiece for 3.2mm, 4.0mm, and 4.8mm rivets. The workpiece must be clamped tightly during riveting.

Apply intermittent force until the rivet mandrel breaks; do not yank with sudden impact force. The broken tail of the mandrel may eject; collect it carefully.

Caulking Gun Use

When loading a cartridge, ensure the piston plate is flush against the bottom of the cartridge and the push rod brake is engaged.

When stopping caulk application, immediately press the brake plate to release thrust, preventing excess adhesive from oozing out.

When cutting the nozzle tip, cut at an angle, matching the opening size to the desired bead width.

Maintenance and Storage

Keep chrome-molybdenum steel blades dry and rust-free. Keep strong magnetic bits away from magnetically sensitive items.

Regularly apply light lubricating oil to the ratchet head. Lubricate the moving joints of the rivet gun quarterly to prevent seizing.

When not using the caulking gun for extended periods, clean off residual adhesive and retract the push rod. Store all tools in a dry and ventilated place, avoiding blade edge impacts.