SM-301 Taped Radial Lead Cutter by Southern Machinery
The SM-301 taped radial capacitor lead cutter from Southern Machinery is a hand-crank bench tool that trims leads of single-side taped capacitors, diodes and LEDs to a 3–20 mm length before insertion, with no electrical power needed. This guide explains how to decide where lead length is controlled, what the manual specifies, how to set up and run the machine safely, how to estimate value with an example formula, and how it feeds a complete THT line with auto insertion, wave soldering and board handling. Built for EMS engineers and buyers who want consistent lead length and fewer rework surprises from a compact, low-cost tool backed by Southern Machinery's global service and spare parts support.
Oct 24, 2026 · Updated Oct 24, 2026 · Southern Machinery
SM-301 Taped Radial Capacitor Lead Cutter by Southern Machinery
The SM-301 is a hand-crank lead cutter that trims the leads of single-side taped radial capacitors, diodes and LEDs to a set length of 3–20 mm before insertion. It needs no electrical power, weighs 12 kg and fits on a workbench, so it suits prototype benches, rework cells and small THT batches. It is one low-cost way to prepare radial leads ahead of a THT line.
Why do radial leads still cause trouble on THT lines?
Most THT problems that look like insertion defects start earlier. Leads that are too long, uneven between batches, or trimmed by whoever had scissors handy will show up later as bent legs, poor seating and rework at the solder joint.
Many small EMS shops and engineering labs treat lead trimming as an afterthought. Nobody owns it, so nobody measures it. The result is a quiet quality leak that never appears as its own line on a report.
What decision are you really making?
You are not choosing a cutter. You are deciding where lead length gets fixed: at the machine, at the operator's hand, or not at all. A simple three-step model helps.
- Define the length. Set one target lead length per component family and write it into the work instruction.
- Fix it mechanically. Let the tool, not the operator, hold the length. The SM-301 does this with an axially adjustable knurled cutter.
- Check it at the first piece. Measure the first cut leads against the target before running the batch.
If a job is small, varied or off-grid, a manual tool is often enough. If volume rises, step up to an electric or inline lead cutter.
What is the SM-301 and what does it cut?
According to the Southern Machinery operation manual (Rev. 2025), the SM-301 is a hand-cranked lead cutter for single-side taped (radial) components. It trims the leads of taped capacitors, diodes, LEDs and similar components to an adjustable length before insertion. The manual lists compact size, high precision, adjustable cut length, low cost and no dependence on electrical power as its features.
Key specifications
| Item | Specification (from the manual) |
|---|---|
| Model | SM-301 |
| Drive | Manual (hand crank) |
| Applicable components | Single-side taped capacitors, diodes, LEDs and similar |
| Cut lead length (L) | 3–20 mm |
| Lead diameter (W) | 0.4–1.0 mm |
| Capacity | 50,000 pcs/h (as listed in the manual) |
| Weight | 12 kg |
| Machine size (L × W × H) | 225 × 190 × 190 mm |
Throughput of a hand-cranked machine depends on how steadily the operator turns the crank, so treat the rated capacity as a manual figure and confirm real output on your own parts.
Main parts you will handle
The knurled cutter, round cutter, hanging wheel (sprocket wheel), feed clamp, tape clamp, crank handle and collection tray are the parts operators touch. The packing list includes the main unit, hexagon key set, crank handle, hanging rod, support bar, instruction manual and collection tray.
How do you set it up and run it?
Load the tape and set the lead length
Remove the cover, hang the tape's sprocket holes on the hanging wheel teeth, and insert the taped components into the feed-clamp track so every hole engages a tooth tip. Leave the gap between the feed clamp and tape clamp slightly wider than the tape so it runs freely, then tighten the star knobs.
To set length, loosen the round-cutter adjusting screw, loosen the knurled cutter fastening screw, and slide the knurled cutter axially to the required lead length. Retighten, so the spring presses the round cutter against the inner side of the knurled cutter, then refit the cover.
Cut and watch the tape
Turn the crank steadily. The hanging wheel feeds the tape and the cutters trim the leads, which fall into the collection tray. If the tape drifts off the tips of the feed teeth, stop immediately and re-seat it.
Safety rules from the manual
- Keep hands and loose clothing away from the hanging wheel, knurled cutter, round cutter and gears while running.
- Fix the machine to a flat, stable workbench and keep the cover fitted.
- The cutters are sharp; handle them with care.
- Do not oil the hanging wheel, knurled cutter or round cutter.
How does it compare with other ways of trimming leads?
| Approach | Where it fits | Watch out for |
|---|---|---|
| Scissors or hand trimming | One-off repairs | Inconsistent length, operator dependent |
| SM-301 hand-crank cutter | Benches, labs, small batches | Output tied to operator cranking |
| Electric auto lead cutter | Steady daily volume | Needs power and floor space |
| Inline cutter on a THT line | Continuous production | Higher investment, line integration |
How do you estimate the value?
Use your own numbers. This is an example formula, depending on configuration and subject to final technical confirmation:
Annual saving = (minutes saved per batch ÷ 60) × batches per year × labor cost per hour − tool cost
Example only: 10 minutes saved × 200 batches × $8/hour gives about $267 per year before tool cost. The inputs are illustrative, not Southern Machinery figures, and the unit price is not specified in source — contact Southern Machinery to confirm.
How does it fit a complete PCB assembly line?
The SM-301 sits before insertion. Trimmed radial parts can feed manual insertion benches or automated auto insertion equipment, and the board then moves on through THT machines, wave soldering and board handling. Southern Machinery, founded in Shenzhen in 2011 and serving 237+ global clients, supplies SMT and THT line solutions with spare parts support and professional training.
FAQ
What does the SM-301 cut?
Leads of single-side taped capacitors, diodes, LEDs and similar components.
What lead length and diameter range does it handle?
3–20 mm cut length and 0.4–1.0 mm lead diameter, per the manual.
Does it need power?
No. It is hand-cranked, so production does not depend on electrical power.
What should I do if the tape drifts off the feed teeth?
Stop cranking, re-seat the tape on the hanging wheel and reset the clamp gap.
How should I maintain it?
Keep the cutting surfaces free of oil, apply light anti-rust oil to other transmission parts, and check screws regularly.
What should you read next?
This is part of our THT preparation series. Next, we cover how an inline auto lead cutter changes the labor picture once batches grow. Check back, or browse the machine catalog.
Ready to specify your lead-cutting step?
Send your component type, lead diameter and target length through the quote page and our engineers will confirm fit, lead time and price.
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