T-8421B/8422B/8452B/8722B/8752B are computer-direct-drive flat-sewing machines with the industry's most energy-saving design. The operation control panel is simple and easy to use. It can be sewn cleanly without oil. It is easy to replace the gauge parts. The jaw is high and the machine chamber is wide, which makes it easy to handle the sewing materials.
This document describes the features and functions of Brother's double‑needle computer direct‑drive sewing machines, including the T‑8421B, T‑8422B, T‑8450B, T‑8452B, T‑8720B, T‑8722B, T‑8750B and T‑8752B models. It covers energy‑saving design, needle‑timing adjustment, fabric‑feeding options, and the oil‑free needle rod system.
The manual also includes technical specifications, safety measures such as needle‑rod drop protection, and instructions for accessories, lubrication, and troubleshooting. Detailed tables list motor power, voltage options, maximum sewing speed, needle spacing and other key parameters. This manual is written in Chinese.
| Maximum sewing speed | 3,000 rpm |
|---|---|
| Maximum sewing speed (high‑speed models) | 4,000 rpm |
| Motor power | 450 W (4‑pole AC servo motor) |
| Power supply | Single‑phase 220 V / Three‑phase 380 V, 400 VA |
| Needle type | DP×5 |
| Maximum needle spacing | 9.5 mm |
The T‑8421B can sew up to 3,000 rpm.
Adjust the position of the cutting cam relative to the lower shaft; no drive belt removal is required.
It uses a 4‑pole 450 W AC servo motor.
A micro‑oil system reduces oil use to one‑fifth of traditional models.