ᐅ Which screws are essential to use when remodeling IKEA Besta units?

Hello everyone, I am currently planning to modify my IKEA Besta system and want to replace some of the standard screws with higher-quality alternatives to improve stability and, above all, to be more flexible for future adjustments. I am particularly interested in which types of screws have proven effective when replacing the standard press-in screws or the thinner machine screws. It would also be great if you could provide recommendations on the lengths, materials, and head types I should consider to keep the assembly just as easy while significantly improving durability—taking into account the original drill holes and connections (so no complete rebuilds, just replacement screws for the existing system). Has anyone had specific recommendations for Besta modifications involving drawer slides or additional shelves? Thanks for your experiences and advice!

Hello Winstonren,

there are several important aspects to consider regarding screws when modifying the IKEA Besta system if you want to improve the original fastenings. IKEA typically uses press-in screws similar to Spax, with coarse threads in relatively soft wood, which is sufficient for standard use but can reach its limits with frequent modifications or heavier loads.

My recommendation:
- For all load-bearing connections and side panels, screws with a full thread made from steel at least galvanized are suitable. Torx screws in sizes 4 or 5 (TX20 to TX25) have proven especially reliable; they provide better grip during driving and reduce the risk of stripping.
- Length: Screws about 40 to 50 mm (1.5 to 2 inches) long are most effective. Shorter screws often don’t reach deep enough, while longer ones can damage the backside or interfere with installed components.
- Head type: Flat-head or countersunk screws with Torx are advantageous because they can be recessed flush and prevent the wood from splitting.
- Material: Stainless steel or galvanized screws prevent rust, especially in kitchens or living spaces where moisture is a factor.

Particularly when using drawer slides or additional shelves, where loads are more concentrated, I recommend screws with high tensile and withdrawal resistance. Wood screws designed for solid wood with deep threads hold better in the particleboard used in the Besta system.

If possible, use screws made of carbon steel or stainless steel, not cheaper, unalloyed steel screws from general hardware stores.

I’m curious about your specific plans regarding load and usage for the modification. Will there be rails, new panels, or extra fastenings added? That could influence the choice of screws.

GUSTAVO56 schrieb:
For all load-bearing joints and side panels, fully threaded screws made of at least galvanized steel are suitable. Torx screws in size 4 or 5 (TX20 to TX25) have proven particularly effective, as they provide better grip when driving in and reduce the risk of over-tightening.

I fully agree with this assessment. Additionally, it is important to ensure that the screws are not too thick, as the pre-drilled holes in IKEA Besta are quite standardized and somewhat narrow. A 4 mm (approximately 5/32 inch) diameter screw with a Torx TX20 head often fits well and can be installed without pre-drilling.

GUSTAVO56 schrieb:
Length: Screws with a length of 40 to 50 mm are most practical.

I also find this point very appropriate. In particular, 45 mm (about 1 3/4 inches) is a good compromise between sufficient holding strength and space requirements.

For mounting drawer slides, shorter screws in the range of 30 to 35 mm (about 1 1/8 to 1 3/8 inches) are often advisable to avoid drilling into the side panels or metal parts.

In summary:
- Galvanized Torx TX20 screws, approximately 4 mm (5/32 inch) diameter
- Length depending on the application, 35 to 50 mm (about 1 3/8 to 2 inches)
- Countersunk head so the screw can be flush with the surface

This ensures that the fastenings are optimized without weakening the material.

Based on my experience with several IKEA Besta modifications, I would like to add the following:

- If you plan to install additional shelves or reinforce the side panels with screws, I strongly recommend pre-drilling pilot holes before screwing in. Although cam screws usually do not require drilling, pre-drilling effectively prevents the chipboard from splitting.

- Here is my step-by-step guide for you:
- Use Torx TX20 screws with a 4.0 mm (0.16 inch) diameter.
- Before screwing in, mark and pre-drill with a thin drill bit of about 3 mm (0.12 inch).
- Preferably use galvanized screws.
- For shelves and drawer slides, use screw lengths of 30–40 mm (1.2–1.6 inches).
- For side panels and frame parts, screws of 45–50 mm (1.8–2.0 inches) length work best.

- Avoid screws with coarse wood threads that tend to grip too deeply, as this quickly weakens chipboard.

- Also, make sure the screws aren’t too thick—a 4 mm (0.16 inch) diameter is ideal. Thicker screws can damage the pre-drilled connections on Besta components.

If you already have specific parts you want to modify, I’m happy to help you identify the right screws with measurements.

Landontau schrieb:
If you plan to install additional shelves or reinforce the side screws, I definitely recommend drilling small pilot holes before inserting the screws.

I want to emphasize this point. When replicating or modifying IKEA Besta units, drilling pilot holes is essential because chipboard tends to split easily, which weakens the joint.

Additionally, I recommend:
- Torx TX20 screws, which fit well into the pre-made connectors and can be easily driven with common cordless drills.
- For most furniture applications, screws with a diameter between 4 mm and 4.5 mm (around 5/32 inch to 3/16 inch) are sufficient.
- Lengths between 35 mm and 50 mm (about 1 3/8 inches to 2 inches), depending on the location. For cross joints or attaching metal guides, shorter screws are preferable.

Material: Stainless steel is ideal to prevent corrosion, especially if the furniture is placed in more humid areas.

My tip: Buy a set with various lengths and sizes so you can choose the right screw for each part, avoiding installation errors.

One more question: How important is the appearance of the screw heads to you? Do you want them fully countersunk at the end, or is a visible screw head acceptable?

I’m always happy to help with recommendations if you provide more specific details.