502 HD Bottom Sewing Machine with Auto Cutter

Model: SewTek

The ST 502 HD sewing machine is a heavy-duty bottom-sewing machine designed to close woven sacks quickly and neatly. It sews the bag's bottom seam with a clean, even stitch, helping bag makers keep their lines running without stopping.

Made for uninterrupted factory use, the ST 502 HD sewing machine with auto cutter trims the thread on its own after each bag, so there is less manual work and less thread waste. With a strong build, simple controls, and easy maintenance, it fits a wide range of woven sack production needs.

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A Trusted Bottom Sewing Machine Manufacturer

Armstrong is a well-known name in woven sack sewing solutions, backed by decades of engineering experience and supported by a service team across India and global markets. Every machine is built in-house and tested before it leaves the floor.

The ST 502 HD brings together a strong, heavy-duty body and simple, reliable working parts to give a clean bottom seam on every bag. It is made for industrial use, so bag makers get steady output, good stitch quality, and a machine that keeps running shift after shift.

What the ST 502 HD gives bag makers:

Clean, even bottom-seam stitching on every woven sack
Auto thread cutting that lowers manual work and thread waste
Built-in bag counting and stacking for smooth, organised output
Bobbinless stitching that keeps the line moving with fewer stops
Low maintenance, long machine life, and easy-to-find spare parts

Armstrong builds the ST 502 HD sewing machine to suit your line layout, bag sizes, and production needs, giving you a dependable bottom-closing solution for everyday woven sack production.

Technical Specifications

The ST 502 HD sewing machine specification below shows the working range, power needs, and size, so you can plan where it sits on your line.

Parameter	Specification
Maximum Bag Width	24 inch
Maximum Bag Length	40 inch
Stitching Range	Adjustable, 10 to 16 stitches per 100 mm
Air Pressure	5 Bar
Power Supply	415 V, 3-Phase, with Neutral and Earthing, 50 to 60 Hz
Machine Dimensions	1500 x 1900 x 1300 mm

Key Features

Works on Many Materials: It stitches PP, HDPE, LENO, and BOPP bags, along with non-woven and multiwall paper sacks. This makes it a reliable laminated woven bag sewing machine for units running mixed bag types.
Bobbinless Stitching: It uses a bobbinless stitching system, so there is no need to stop and refill bobbins. This means fewer stoppages and higher output.
Adjustable Stitch Length: The gap between stitches can be set from 10 to 16 stitches per 100 mm, to match different bag types and seam strength.
Single Needle Option: The machine can be easily changed to a single-needle setup when the job needs it.
Automatic Lubrication: A full auto-lubrication system with oil recycling oils the moving parts on its own, which protects the machine and gives it a longer life.
Strong Build, Easy Service: It is made for rough factory floors and needs little maintenance. Spare parts are easy to get, so downtime stays low.

FAQs – 502HD Bottom Sewing Machine with Auto Cutter

What is the ST 502 HD Sewing Machine used for?

It is used to sew and close the bottom seam of woven sacks, such as PP and HDPE bags, in bag-making units.

What types of bags can it sew?

It works on PP woven, HDPE, LENO, and BOPP laminated bags, plus non-woven and multiwall paper sacks. It is a reliable bag sewing machine for daily production.

Does the ST 502 HD have an automatic thread cutter?

Yes. It cuts the thread on its own after each bag, which saves time and reduces manual work.

What is the maximum bag size it can handle?

It can stitch bags up to 24 inches wide and 40 inches long.

What power supply does it need?

It runs on a 415 V, 3-phase supply with neutral and earthing, at 50 to 60 Hz.

Which industries use the ST 502 HD?

It is used across rice mills, fertilizer plants, cement units, and food grain packing. This makes it a dependable fertilizer bag sewing machine, cement bag sewing machine, and food grain bag sewing machine for high-volume packaging.