A riddle bucket is about the simplest attachment you can put on an excavator: a bucket with bars instead of a solid back, shaken so fine material drops through while rocks, rubble and roots stay behind. Simple doesn't mean there's no skill to it, though. How you load and shake it makes a real difference to how much you sort in a day and how hard you work your machine.
1. Pick the Right Size and Bar Gap
Choose a bucket built for your excavator's weight. Going bigger than your machine is designed for means slower cycles and more strain on the pins and rams every time you shake a full load. Our excavator riddle buckets run from a 600mm bucket for 1–2 tonne minis up to 1350mm for 18–25 tonne machines, each built for its weight class.
Then think about the gap between the bars. The gap decides the largest piece that falls through, so match it to what you want to keep. If you're reusing topsoil and only want to lose stones and roots, the standard gap works well. If you're making a specific size of fill, ask for a custom bar spacing when you order.
2. Load It Properly
- Don't overfill it. Material piled high in the bucket never reaches the bars, so a heaped bucket sorts slowly. A part-filled bucket lets everything move and fall through.
- Dig from the face of the pile rather than scraping along the ground, so you don't pick up material you've already sorted.
- Keep the bucket close to the machine when you shake it. Working at full reach puts more strain on the boom and reduces stability.
3. Shake with Short, Controlled Movements
Lift the loaded bucket just above the sorted pile and rock it back and forth with short, quick movements of the bucket ram, adding small dipper movements if material is slow to fall. Let gravity do most of the work. Big, violent shakes and slamming the bucket against its end stops don't sort any faster, but they do hammer your pins, bushes and ram seals.
Keep the bucket low over the pile so the screened material lands where you want it instead of bouncing and scattering. When only oversize is left, swing round and tip it on a separate heap.
4. Work with the Weather, Not Against It
Riddle buckets work best on dry or slightly damp material. Wet, sticky soil and clay bridge across the bars and stop falling through, and no amount of shaking fixes that. Where you can, stockpile the material and riddle it once it has dried out. If you regularly need to screen damp material, a screening bucket is the better tool because its turning drum breaks clods up. Our comparison of riddle buckets and screening buckets goes through the trade-offs.
5. Set Up Your Piles Before You Start
Plan where the unsorted heap, the screened material and the oversize will go, so you can load, shake and tip with the smallest possible slew. Short swings mean faster cycles and less fuel. Keep people well clear of the working area, as stones can bounce off the pile when you tip.
What You Can Riddle
- Topsoil with stones, roots and old brick in it
- Hardcore and crushed concrete, to separate usable fill from oversize
- Demolition waste, to recover reusable material before disposal
- Quarry and pit material, to separate large rock from smaller stone
- Land clearance spoil, to pull roots out of the soil
Looking After a Riddle Bucket
- Grease the pins every day. Shaking works the pivot points hard, so they need regular grease.
- Check the teeth and cutting edge. Worn CAT J teeth can be swapped one at a time, and replacing them early protects the HB400 edge behind them.
- Look for bent or cracked bars. A bent bar changes the gap and lets oversize through. Get damage repaired before it spreads.
- Clear stuck material at the end of each day so it doesn't set hard between the bars.
Frequently Asked Questions
Is a riddle bucket bad for my excavator?
Not if you use it sensibly. Short, controlled shakes, a part-filled bucket and well-greased pins keep wear down. Problems usually come from slamming the bucket or overfilling it.
Can I dig with a riddle bucket?
You can break into loose heaps with the teeth and scoop from them, but it isn't built for digging hard ground. Use a digging bucket to excavate, then riddle the spoil.
What size riddle bucket do I need?
Match it to your excavator's operating weight. A 3 tonne mini digger suits the 2–3.5 tonne riddle bucket, and a 13 tonne machine suits the 10–14 tonne riddle bucket. Have your pin measurements ready so it arrives with the right fittings.
What's the difference between a riddle bucket and a land rake?
A riddle bucket sorts material you've dug up. A land rake combs stones and debris out of loose ground without digging it. If the stones are on the surface, a land rake is quicker.
Need help choosing? Send us your machine details and we'll match the right riddle bucket and linkage, or browse the full excavator sorting buckets range.
