Workshop services
Bandsaw sharpening
& welding
We sharpen narrow and wide band saw blades, butt-weld blade lengths, and set and tension using Armstrong equipment. Courier from anywhere in Southern Africa — we work through the full maintenance sequence and return blades ready to run.
The maintenance sequence
What we do in the correct order
Levelling, tensioning and straightening must be done in sequence — and levelling must always come before tensioning. Skipping steps or doing them out of order produces blades that run erratically and crack at the gullets. We follow the correct sequence every time.
Inspect & clean
Every blade is cleaned of resin before inspection. We check for gullet cracks, broken tips, body cracks and signs of previous incorrect maintenance before deciding the scope of work.
Levelling
The blade is rolled flat on the tensioning bench before any other work. Lumps and bulges from sawing must be removed first — tensioning over an unlevel blade locks the fault in permanently.
Tensioning
The centre of the blade is elongated by rolling so that the crosswise profile matches the crown of the wheel. We check the light gap against the correct target for the blade width (100mm → 0.3mm through to 400mm → 2.7mm).
Straightening
The back edge is elongated to concentrate tension at the toothline during sawing — this gives the teeth the rigidity needed to cut straight under feed load.
Setting
Swage setting or spring setting per your timber application. Set is matched to timber type: pine 0.4–0.6mm per side; hardwood 0.3–0.5mm per side. Armstrong swage and shaper equipment.
Sharpening
CBN wet grinding for narrow band blades. Correct grinding angle for tooth shape — LS, S or SB. Gullet bottoms polished with carbide deburrer at ≥28,000 RPM to remove friction martensite and prevent crack initiation.
Welding (if required)
Flash-butt welding for joining coil to length or repairing clean breaks. The weld is annealed at 400°C immediately after welding, ground flush to 0.03–0.04mm below plate thickness, and re-levelled over the joint.
Gullet deburring is not optional. After every sharpening session, friction martensite forms in the gullet bottoms — a glass-hard, brittle layer that initiates fatigue cracks under the bending stresses of sawing. We run a carbide deburrer at ≥28,000 RPM across every gullet bottom as standard. Many sharpening operations skip this step. We don't.
Release tension before storing blades. If a blade is stored on the machine or in a coiled state under full tension, stress cracks propagate from the gullets overnight. Always release tension at end of shift. If you're sending blades in that have been stored under tension, let us know — we'll check for existing crack initiation before proceeding.
- Your name and contact phone number
- Machine type and wheel diameter (helps us confirm blade spec is correct)
- Timber species being cut — determines correct set amount
- Whether welding to a new length is required — supply loop length or wheel centre distance
- Description of the problem if fault-finding (drift, cracking, rough cut, etc.)
5 Rapid Street, Riverside Industrial Park
Nelspruit / Mbombela, 1201
Blade types we service
Narrow band, wide band & frame saw
Narrow band — Wood-Mizer & rip saws
35mm – 75mm blades for portable sawmills and narrow band rip saws. CBN wet grinding, correct set per grade (M-Gold, Gold, Silver, DH, bimetal). Guide rollers checked and supplied if needed.
Wide band — log & rip saw
80mm – 311mm blades for large log bandsaws and band rip saws. Full bench work sequence — levelling, tensioning, straightening and sharpening. BWB and Uddeholm blades stocked if replacement is needed.
Frame saw blades
175mm – 180mm swage frame saw blades serviced to correct set and sharp geometry. Frame saw blade operation is demanding — set symmetry is particularly critical for straight cutting.
| Parameter | Normal range | Notes |
|---|---|---|
| Machine strain | 100–150 MPa (normal) · 200–250 MPa (high) | High strain gives better accuracy. High-tensile steel recommended at 200–230 MPa |
| Set — pine (soft) | 0.4–0.6mm per side | Spring-set and swage-set teeth |
| Set — hardwood | 0.3–0.5mm per side | Oak, mahogany, dense species |
| Set — very soft (poplar) | 0.5–0.7mm per side | Coarse, long fibres spring back strongly |
| Set — frozen or dry softwood | 0.3–0.5mm per side | Frozen cuts cleanly with minimal fibre spring-back |
| Gullet deburrer speed | ≥28,000 RPM | Lower speeds create friction martensite rather than removing it |
| Weld anneal temperature | 400°C / 750°F | Immediately after welding to prevent untempered martensite |
| Storage coil radius (min) | 150 × blade thickness | Tighter radius fatigues steel at the bend point |
Send blades in for service
Courier to Nelspruit — we'll return them tensioned, set, sharpened and ready to run. Quote before we proceed on any work above a standard sharpen.