Use a straight or bulb head to probe and open soft clogs and to pass tight traps, a spade or C-cutter to bore through packed paper and grease, a grabber or retrieving head to pull out hair, wipes and objects, and a root saw or blade cutter sized just under the pipe diameter for roots. Start small, sample the clog, then step up.
- The head does the work; the cable only delivers torque. Wrong head, wasted effort.
- Start with a small probing head to find and sample the clog, then switch to a cutter sized for the job.
- A cutter should be slightly smaller than the pipe's inside diameter; a cutter the full size of the pipe can catch joints and damage fragile pipe.
- Root saws and blade cutters are for sound pipe with root intrusion, not for clay or Orangeburg that is already breaking up.
- What comes back on the head is diagnostic evidence; look at it before you rinse it.
01 /What do the different auger heads do?
Auger heads fall into three families: probing heads that find and open the clog, cutting heads that bore and shear it, and retrieving heads that catch it and bring it back. Choosing the head is a sequence, not a single decision. Most drain cleaners start with a probing head, look at what comes back, and then switch.
| Head | Family | Best for | Avoid when |
|---|---|---|---|
| Straight (open coil) | Probing | First pass, finding the clog, tight traps | Dense or packed clogs; it just pokes a hole |
| Bulb (drop head) | Probing / retrieving | Hair and soft debris in small drains; bulb steers through bends | Large pipe where it cannot grip anything |
| Funnel or corkscrew | Retrieving | Hair, string, fibrous plugs close to the fixture | Grease; it just smears |
| Spade (arrow) | Cutting | Packed paper, sludge, grease plugs in branches and mains | Pipe smaller than the spade width |
| C-cutter / U-cutter | Cutting | Opening a larger channel in grease or soft buildup | Fragile clay, Orangeburg, cracked cast iron |
| Grabber / retrieving head | Retrieving | Wipes, rags, feminine products, broken-off material | Solid objects wedged at a fitting |
| Root saw / sawtooth cutter | Cutting | Root masses at joints in sound pipe | Pipe already offset, cracked or collapsing |
| Blade cutter (2 or 4 blade) | Cutting | Heavy roots, final pass to widen the channel | Plastic pipe with sharp bends; old damaged pipe |
| Flexible leader | Accessory | Helps any head pass tight bends and traps | Nothing specific; it reduces cutting force |
02 /Which head should you start with?
Start with the smallest head that will reach and sample the clog, usually a straight or bulb head on small drains and a small spade on mains. The first pass has two jobs: confirm where the clog is and bring back a sample of what it is. Only after that should you commit to an aggressive cutter.
- Probe
Straight or bulb head. Find the distance to the clog and feel whether it is soft (gives), fibrous (grabs) or hard (stops dead).
- Sample
Pull back and look. Hair, paper, grease, wipes, roots, sand, rust scale or pipe fragments each point to a different next head.
- Open
Switch to a spade or C-cutter for soft plugs and grease, a grabber for wipes and rags, or a root saw for roots.
- Widen
Step up to a larger cutter, no bigger than slightly under the pipe's inside diameter, and make several passes.
- Finish and verify
Flush under load. If the line is a main, this is the moment to ask for a camera inspection.
03 /How do you size a cutting head to the pipe?
Size a cutting head so it is slightly smaller than the pipe's inside diameter, commonly about 1/2 to 1 inch under on 4-inch mains. A cutter that fills the pipe completely will catch on every joint, offset and fitting edge, and in older or fragile pipe it can chip bells, tear liners or break brittle sections.
| Pipe | Probing head | First cutter | Finishing cutter |
|---|---|---|---|
| 1-1/2 to 2 in | Bulb or straight | Small spade | Not usually needed |
| 3 in | Straight or small spade | About 1-1/2 to 2 in spade or C-cutter | About 2-1/2 in |
| 4 in | Small spade | About 2 to 3 in spade or root saw | About 3 to 3-1/2 in blade or root saw |
| 6 in | Spade | About 3 to 4 in cutter | About 4-1/2 to 5 in blade |
Stepping up through two or three sizes is gentler and more effective than going straight to the largest cutter. The small cutter opens a path for water, which then helps carry debris away as the larger cutter widens the channel.
04 /Which heads are safe for old or fragile pipe?
For old or fragile pipe, use probing and retrieving heads and small spades, and avoid aggressive root saws and blade cutters until a camera has confirmed the pipe is sound. The concern is not the steel of the head alone but where it meets the pipe: at joints, cracks and offsets.
- Vitrified clay tile: common in older Canadian neighbourhoods. The pipe body is hard, but joints are the weak point and roots often enter there. Moderate cutters are usually fine in sound clay; stop if chips come back.
- Orangeburg (bituminous fibre): a tar-impregnated fibre pipe used in some houses mainly from the 1940s to the 1970s. It deforms and blisters with age. Aggressive cutters can tear it; if black fibrous material comes back, stop.
- Cast iron: inner walls can carry heavy scale (tuberculation). Standard cutters skip over scale; descaling heads and chain knockers are specialist tools. Badly corroded cast iron can crack.
- ABS and PVC: smooth and tough, but sharp cutters can gouge the wall at tight bends. Use a flexible leader and correctly sized heads.
- Lined pipe (CIPP): a relined pipe should only be cleaned with methods the lining installer approves. Aggressive cutters can damage liners.
If you do not know what your lateral is made of, the Calgary and Alberta page outlines the materials typical of different construction eras, and a camera inspection will confirm it. Where heads and cables can harm pipe and fixtures, and how to avoid it, is covered in can a drain snake damage pipes.
05 /What is a root saw, and when does it help?
A root saw is a toothed or bladed cutting head designed to shear through root masses that have grown into a sewer pipe through a joint or crack. It spins at the end of heavy drum or sectional cable and cuts roots flush-ish with the pipe wall, restoring flow.
It helps immediately: flow returns and the line may stay clear for months. It does not remove the entry point, and roots respond to cutting by regrowing from the stubs. A root saw is therefore a maintenance tool, not a fix. The permanent options are pipe repair, relining or replacement. The sister site SewerRoots.ca covers root intrusion, which trees cause it, and prevention in depth.
06 /How do you maintain auger heads?
- Rinse and dry heads after each job; sewage residue corrodes steel quickly.
- Check blades for chips, bent teeth and loose rivets. A cracked blade can break off in the line.
- Check the coupling or connector for wear. A worn connector can release the head inside the pipe.
- Oil connectors lightly and store heads separately from the cable so teeth do not nick it.
- Replace heads that have been bent; they wobble and chew the pipe wall.
Cable care after the job is in cleaning and storing a drain auger. For the machine that carries each head, see types of drain augers and the auger cable size chart; the Auger Cable Sizer suggests a starting head from the line and the clog type. If the head comes back greasy, rooty or scaled, read when augering is not enough, or request quotes from contractors who can also jet or inspect.
FAQQuestions people ask
What is the best auger head for hair clogs?
A bulb, funnel or corkscrew head on 1/4-inch cable. They grab hair and pull it back out rather than pushing it further down the drain.
What auger head cuts roots?
A root saw or blade cutter on heavy drum or sectional cable, sized slightly smaller than the pipe. It clears flow, but roots regrow from the cut stubs.
Can a cutting head damage my sewer pipe?
It can, especially in fragile pipe such as Orangeburg or cracked clay, or when the cutter is the full diameter of the pipe. Start small, step up, and stop if pipe fragments come back.
Should the cutter be the same size as the pipe?
No. Cutters are usually sized somewhat smaller than the pipe's inside diameter so they do not catch on joints or offsets.
What does it mean if grease comes back on the head?
The line has grease buildup on the pipe wall. Augering opened a channel but did not clean the wall, so jetting is usually the better long-term treatment.
What is a flexible leader?
A short length of very flexible cable fitted between the main cable and the head. It helps the head turn tight bends and pass traps.
NETWORKGo deeper across the HAUSE Sewer network
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