What Size Trommel Drum Do I Need? (Let’s Talk Length and Diameter)
If you’re trying to figure out what size trommel drum you need, you’re probably wondering about two things: length and diameter. These aren’t just numbers you pick out of a hat—they make a massive difference to how your machine performs, how easy it is to run, and how well it fits into your site.
Here’s how I’d decide, and what you should be thinking about before you spend a penny:
First up: Diameter
The diameter of your trommel drum is basically how wide the drum is. Bigger diameter = more capacity. If you’ve got loads of material to get through, or if you’re dealing with bulky stuff that doesn’t flow well, go bigger. But—big isn’t always better. A big drum takes up more space, costs more, and can be overkill if you’re not running high volumes.
Typical diameters: Most small to midsize operations are fine with 1.2m to 1.8m diameter drums. Big commercial setups might go 2m+.
Why go bigger? You need higher throughput, or you’re screening large, awkward material.
Why go smaller? Lower volumes, tighter spaces, or you want a more compact, nimble machine.
How do you decide? Be honest about how much you need to process per hour. If you’re only running a few skips a day, a 1.2m drum might be plenty. If you’re flat out with lorries tipping all day, go bigger.
Now: Length
Length is how long the drum is from end to end. A longer drum gives the material more time to tumble and separate, which means better screening (especially if you want a really clean product). But again—longer means more machines, more cost, and more site space.
Typical lengths: 3m to 5m covers most jobs. If you want super-fine screening or you’re dealing with tricky, sticky material, go longer.
Shorter drums: Good for rough screening or when you’re tight on space.
Longer drums: Better for splitting out fines, or if you want to run the drum faster without losing accuracy.
How do you decide? Think about your end product. If you want a really clean, fine output, go longer. If you’re just taking out the big lumps, shorter is fine. Also, look at your site—can you actually fit a 5m drum, or will it block everything else?
A Few Practical Tips
Don’t just copy someone else’s setup. Your material, your volumes, and your site are unique.
If you’re replacing a drum, measure your old one carefully. Don’t assume “standard” sizes.
If in doubt, sketch your site out on paper and see what actually fits—don’t trust your memory!
Talk to someone who’s built or supplied drums before. They’ll know what works for your kind of material.
Bottom line:
Go as big as you need, but no bigger. Bigger diameter = more capacity. Longer drum = better screening. But both = more cost and more space. If you’re not sure, get advice before you buy. The right size drum will save you a fortune in headaches, downtime, and wasted material.
Still stuck? Give us a call. We’ll talk you through it, no nonsense.
