When your jobsite demands clean, separated and perfectly sized material, proper screening makes all the difference. Whether you’re working with rocks, stones, gravel, recycled concrete, recycled asphalt, recycled bricks, sand or dirt, the right screener turns mixed piles into money piles. Let’s break down how to screen different materials, what size screens to use, and which machines get the job done. One size fits all does not necessarily apply when considering the numerous types of materials and the wide variety of sizes that may be required. Other material conditions to consider when selecting the appropriate screening system would be moisture content, gradation, abrasiveness, stickiness, organic content, contaminants, dust creation, etc.
When trying to select the one size fits all screening system, one must consider what screening system can achieve results in 70% or more of the materials you one is handling. It is rare if not impossible to have one screening system that can effectively screen all materials. There are more popular as well as generic systems that can be used for most materials. Vibratory inclined screening systems are most popular because they are effective in most conditions and materials. They are quite versatile and can easily be fitted with a variety of screen mesh sizes to achieve the desired results. Screen mesh can be installed and removed at will with minimal costs contributing to the popularity of vibratory inclined screens.
Why Screening Matters
Many projects have stringent criteria on the size of material that must be used. Asphalt rap (Recycled Asphalt Product) may require 100% passing 9/16” for example. Pipe bedding to be used to cover and pipe and line trenches may require 3/8” material. In addition to size requirements, the gradation of the material may come into play. The term gradation would refer to the percentages of various sizes that make up the entire sample.
For example, the California DOT specification for recycled concrete is currently 100% passing 1” and 90% passing ¾”, etc. etc. The gradation requirements can specify the percentages of various sizes by indicating a maximum or minimum percentage of various sizes. Screening is about control so you can successfully sift raw, oversized, and irregular material into defined size piles while trying to achieve not only proper particle sizing but also trying to achieve possible gradation requirements.. Whether you require road base, rip rap, clean rocks, landscaping materials, or fill dirt, size consistency will most likely be very important.
Properly sized material can also add value to the product. 3/8” clean material may be worth more than 2″ minus, for example. Screening may not only allow you to hit various requirement parameters but also make you more profits. Therefore, adding a screening system to any crushing operation can pay serious dividends. In addition, being able to produce various sizes will offer you more versatility and flexibility when bidding jobs. After all, being able to produce the right size or sizes of material, will make all the difference when your jobs change and size requirements change from project to project.
Screening 101 – General Tips on Inclined Screens
When working with inclined screens it is common to calculate the square area of the screen deck or decks to determine the possible production capability of the screen. To keep it simple, a 4-foot X 10-foot screen will not have the capability of a 6-foot X 16-foot screen. Assuming both screens are traditional and have the same parameters as material size and screen mesh openings, the larger screen will effectively produce more material per hour.
Traditional can loosely mean they are mounted on a 15 to 18 degree angle with springs either coli or rubber in all four corners of a basic rectangular shape. The vibratory mechanism in a traditional screen has a mechanism RPM in the range of 700-1100 RPM. Additional weights can be mounted on the external flywheels to create “throw” which is a term used for the intensity of the vibration.
An increase in throw creates a more violent vibration. The higher the RPM and the more throw in a vibratory screen will translate into a more effective screening system especially when screening difficult materials.
How to Screen Rock
Most rock screening starts with a vibrating deck and a heavy-duty mesh screen. Feed the rock in, and let the machine do its thing. Yes, there are grizzly bars on feeder systems that act like screen mesh to some extent. Grizzly bars are elongated bars that have adjustable spacing to allow fines to pass through while allowing larger chunks of material to feed forward. Vibrating Feeders are similar to vibrating screens in that they move material while providing some screening.
Tips for screening rock:
- Use Vibrating pan or grizzly feeders as well as larger heavy duty mesh or punch plate (1″–3″) for separating big chunks like rip rap.
- Use an infinite number of screen mesh sizes, various patterns and wire diameters to achieve maximum results. Patters such as elongated slots may be substituted for square openings in certain applications. The important thing to remember is to match the screen mesh with the material and the desired output size.
- If you have wet rock, you may have to take additional precautions such as pre-screening in order to prevent blinding the finer mesh.
Recommended Machine: The Rebel Crusher/screener combination is considered the “SWISS ARMY Knife” of the industry because of its incredible versatility having the ability to not only screen materials but to crush them in one pass. The REBEL CRUSHER is well known for its ability to tackle tough projects where material conditions vary and can be extremely tough. It’ll crush and/or separate rock, recycled concrete, recycled asphalt, recycled bricks, gravel and most other materials while spitting out various perfectly sized product piles consistently.
Trommel Screens vs Inclined Screens – A detailed comparison across applications, design, and performance
Basic Design & Operation
Trommel Screens
- Type: Rotating cylindrical drum with perforated screens.
- How it works: Material enters the drum and is lifted by internal flights as it rotates, then falls through holes based on size.
- Separation: Based on particle size — undersize passes through, oversize exits the end.
Inclined Screens
- Type: Vibrating flat screen deck at an angle (often 15–25°).
- How it works: Material moves across a vibrating surface; finer particles fall through the screen while larger particles travel across to discharge.
- Separation: Based on vibration and stratification.
Applications
Trommel Screens
- Common in:
- Recycling (e.g., compost, MSW)
- Mining (soft materials)
- Topsoil/aggregate screening
- Gold recovery (placer deposits)
- Best for:
- Wet/sticky materials
- Low abrasion materials
- Coarser separations (often >10 mm)
Inclined Screens
- Common in:
- Mining & aggregates
- Recycled concrete
- Recycled asphalt
- Recycled bricks
- Sand & gravel
- Coal
- Best for:
- Dry, hard materials
- Finer separations (can go <1 mm)
- High-throughput production
Efficiency & Capacity
| Feature | Trommel Screens | Inclined Screens |
|---|---|---|
| Screening Efficiency | Lower (~60–75%) | Higher (~85–95%) |
| Throughput | Lower | Higher |
| Clogging/Blinding | Less likely (self-cleaning) | More likely (needs cleaning) |
Maintenance & Durability
Trommel Screens
- Maintenance: Relatively low; fewer moving parts.
- Wear: Outer drum wears over time, especially with abrasive materials.
- Blinding: Handles moisture better, less prone to clogging.
Inclined Screens
- Maintenance: More frequent; vibrating motors, springs, screen decks.
- Wear: Can be more durable with hard materials.
- Blinding: More prone if material is sticky or wet.
Screen Size Guide
Here’s a quick reference for common screen sizes by material:
| Material | Common Screen Sizes |
|---|---|
| Rock | 1″, 2″, 3″ |
| Gravel | ¾”, ½”, ⅜”, <¼” |
| Asphalt | 1″, ½”, ⅜” |
| Dirt | ½”, ¾”, 1″ |
Want to go finer? Add a second deck or use a trommel with a built-in wash bar.
Best Screening Machines for All Jobsites
If you need to screen multiple materials including rock, gravel, asphalt, and dirt, our Rebel Crusher and Screener can handle it all. It’s mobile, versatile, legal dimensions for travel, and built simply for contractors who don’t have time to babysit a machine.
Frequently Asked Questions (FAQs)
What’s the best machine to screen rocks and gravel?
The Rebel Crusher/screener is ideal for rock and gravel especially when crushing may be required. It separates large chunks, fines, and mid-size material with minimal adjustment.
Can I use the same screener for dirt and asphalt?
Yes. Just change the screen size to match the material. Use larger screens for asphalt and finer mesh for dirt.
What screen size should I use for landscaping gravel?
It depends on the particular specification, but commonly ¾” or ½” works great for landscaping gravel. Use ⅜” for decorative or walkable gravel.
Can I separate rocks from dirt without a machine?
You can, but it’s slow. A powered screener handles this in minutes not hours.
How do I prevent screen blinding when screening wet material?
Use punch plates or add a spray bar if you’re screening wet, sticky, or clay-heavy loads. Also, changing the size of the screen mesh to match th feed materials and desired output size will help. There is a relationship between the size of the screen mesh and the feed that should be adhered to. Imagine putting 10”minus material on a ¼” screen mesh. 99% of the material will not pass through.
However, if you put a 5” top deck and a ¼” bottom deck on the screen, you would not only be more efficient, but the screen would be more balanced. The relationship between screen mesh sizes and feed is not drastic and compatible.
Ready to Start Screening?
Yes, in addition our most popular REBEL CRUSHER/SCREENER, we have dedicated screens, mobile and portable screens, vibratory screening bucket attachments like SWING-SCREEN, etc. We also have Portable Wash Plants that incorporate inclined screens with spray/wash bars when gravel and stones require separation and washing at the same time.
If you’re tired of guessing and want clean, sellable material fast, check out our screening machines. We’ll help you find the right model for your jobsite, your budget, and your material mix. Contact us for more detailed information and to be sure you are selecting the appropriate machine for all or at least most of your needs.