ᐅ Which screws are suitable for retrofitting IKEA BESTA units?

Hello everyone,

I am planning to reinforce my Ikea Besta shelving unit and am not sure which screws are best suited for this. Since most original screws tend to be replaced or lost over time, I am looking for recommendations on the type, length, and thread of screws that are specifically suitable for retrofitting BESTA furniture without compromising stability or appearance.

I am also interested in whether stainless steel screws are better than zinc-plated steel ones, and if certain screw types are more appropriate for different parts of the BESTA system (e.g., side panels, back panel, shelves).

Does anyone have good experiences or tips on what to pay attention to when upgrading? Thanks in advance!

I would recommend using M4 screws with a length of 16 to 20 mm (0.63 to 0.79 inches), preferably galvanized.

Stainless steel is nice, but galvanized is usually sufficient for home use. The original fasteners are mostly in this size.

For back panels, special washer head screws are often suitable.

sarGabriel schrieb:
I would recommend using M4 screws with a length of 16 to 20 mm (about 0.6 to 0.8 inches), preferably zinc-plated.

However, I would like to point out that not all M4 screws are the same. The thread depth and the screw head design affect how strong the connection will be. Zinc-plated screws can rust faster in moist conditions, so stainless steel is often the more durable option.

Additionally, you should check whether you need standard machine screws or particleboard screws, as the material properties for particleboard are quite different. Ikea typically uses medium-thread particleboard screws for their BESTA range to avoid splitting the wood.

Most BESTA components are made from wood-based panels, which are best fastened using particleboard screws. These screws have a coarser thread that cuts well into the wood and ensures long-lasting grip.

- Type: Particleboard screws (sometimes also called universal wood screws)
- Diameter: M4 or M5, depending on the connection point
- Length: Varies by component, from 16 mm (for thinner parts) up to 30 mm (for thicker areas or where multiple panels are joined)

Galvanized screws are sufficient if the furniture is used indoors. Stainless steel is better when moisture is a factor – for example, in kitchens or damp rooms.

An important note: Most connections in the BESTA system use screws with a countersunk head so the screw head sits flush or slightly recessed.

How exactly do you want to reinforce the shelf? For example, with corner brackets or additional shelves? This would also affect your choice of screw.

Johnathon schrieb:
How exactly do you plan to reinforce the shelf? For example, with corner brackets or additional shelves? That would also affect the choice of screw.

Thank you for the detailed information. The plan is to stabilize the frame on two sides using additional boards because the shelf wobbles a bit. I also want to add extra shelves.

The side panels and shelves are made of 16 mm (5/8 inch) particle board. To what extent should I consider different load types when choosing screw length and head type? Are there specific screws that perform better under shear forces?

Can I use universal particle board screws for everything, or are different screws recommended for the reinforcing boards? I would like to avoid having to make two separate purchases if possible.

kiixnu schrieb:
The plan is to reinforce the basic frame on two sides with additional boards because the shelf is a bit wobbly. I also want to add adjustable shelves.

In this case, I recommend using countersunk screws with M5 threads for the reinforcement plates, as they can handle higher torque and thus provide better stability. The length should be at least 25 mm (1 inch) to ensure enough grip in the 16-mm (5/8 inch) particleboard.

For the adjustable shelves, M4 x 16 mm (5/8 inch) particleboard screws are usually sufficient. It’s important not to use screws that are too long to avoid splitting the material.

Using multiple screws distributes the load better — so it’s preferable to use more thinner screws rather than fewer thicker ones.

If possible, you can also install angle brackets with elongated holes, which add extra stability without complicated fastening.