When gullets fill with chips, or chips weld to the tooth face, the blade no longer cuts on the tips. It rubs on a pad of metal. A shiny kerf, a dull or suddenly shrill sound, and feed that will not enter often mean packing, not a “soft” blade. Aluminum, some stainless, and gummy alloys show it first; carbon steel will pack too if TPI is too fine or coolant stops. Stop, look at the gullets and faces, and clean them before you change pitch or add lubrication. More pressure welds the chip harder and leads to stripped teeth or a broken band.
Packed chips, welded chips, and a fully clogged line
- Packed chips: gullets are full, the blade is lifted, chips change from curls to powder or mud.
- Chip welding: a lump of work material is stuck to the face or tip. Aluminum shows this clearly; glazed stainless can pick up metal too.
- Clogging: a whole stretch of teeth is filled, and long packs squeeze out at the guides and kerf.
- Versus normal wear: wear dulls the tip while the gullet stays empty. Packing fills the gullet while the tip may still be there.
Aluminum selection is in How to Choose a Band Saw Blade for Aluminum. Missing lubrication is in Coolant and Lubrication. Too-fine pitch is in How to Choose Band Saw Blade TPI.
Causes and order of work
| Symptom | More likely cause | Do this first |
|---|---|---|
| Aluminum gums at once, kerf shiny | No lube, TPI too fine, low speed with light feed | Stop, clean teeth, restore lube, check pitch |
| Stainless gets slipperier as you cut | Dwell and work-hardening plus fine teeth that cannot clear | Stay in the cut, check coolant, do not polish |
| Solid heavy section, chips cake into a biscuit | Pitch too fine or feed vs clearance mismatch | Ease feed, clear chips, then consider coarser pitch |
| Flood coolant on, still packing | Nozzle not in the kerf, or dirty fluid | Aim the nozzle, change or clean the tank |
| Cleans up, packs again immediately | Spec or parameters still wrong, not a dirty rag | RFQ with the old blade and chips; do not burn a stack of blades |
Clean with a brush or a wood stick, working chips out of the gullet. Do not push fingertips onto the tips. Do not wipe welded aluminum off on the work at speed. On thick-wall pipe, the air gap after the first wall can carry welded chips into the far wall; see How to Cut Thick-Wall Pipe.
After you clean, how to keep gullets open
- Chips should be curls or short spirals, not powder. Powder usually means rubbing, not cutting.
- Aluminum needs lubrication; stainless needs continuous feed and coolant. Do not use one “fine and slow” setup for both.
- If a new blade packs on the first cuts, check TPI and lubrication before you blame the band. Break-in feed is already light, so the teeth must not glaze; see Break-In.
- Send material, section (solid/tube/profile), coolant method, and a tooth-face photo through Blade Finder or Request a Quote. DEKOLY can help confirm a specification; it will not require a product swap without the chips and the tooth face.
FAQ
Does packing always mean I must go to a coarser TPI?
Coarser pitch is often in play, but first rule out a stopped coolant line and a nozzle that misses the kerf. Too coarse on thin wall strips teeth. Use the section and the old blade.
Should I grind welded aluminum off the teeth?
A wheel often takes the tip and the set with it. Stop and clean with a brush, a wood stick, or whatever the blade maker allows. Retire a blade whose tooth form is already gone.
Is resin packing on wood the same problem?
The gullet is full in both cases, but cleaning and lubrication are not. Do not pour metal emulsion on a wood blade. Say resin, wet stock, or frozen wood on a wood RFQ.
Are chip photos useful on an RFQ?
Yes. Curls, powder, or metal welded to the tooth tells more than “it will not cut.” Send them with a close-up of the tooth face.