MDF is one of the quickest growing alternatives to lumber for furniture making and cabinetry. It’s pocket-friendly, accessible, easy to work, and looks great painted.
However, while MDF is stable enough for various constructions, it is not very tough. In fact, what many first-timers are unsure of is whether it’s possible to screw into MDF, especially near the edges.
There’s always the fear of the board splitting from the screws going in. Another concern is the screws being unable to attach pieces tightly.
So, can you screw into MDF? You can screw into MDF by using long, narrow, flat, straight-shanked screws with medium to coarse grain. Begin with a pilot hole to prevent the MDF from splitting or the joint from coming loose.
Read on to learn more as we explore the best kind of screws to use with MDF. We also provide expert tips and tricks for securing your MDF with screws successfully.
What Is MDF And Can You Use Screws With It?
Medium-density fiberboard, widely known by the acronym MDF, is a type of synthetic board. It is manufactured using wood fibers and resins.
The wood fibers and resin mixture is held together by glue and pressure treated (pressed). Everything is compressed before the glue dries.
This type of construction is the primary reason why MDF is prone to splitting when screwed. It doesn’t have a robust profile like solid wood thus has an inferior screw-holding capacity.
Also, as the screw goes in, it acts as a wedge, particularly fat screws and the tapered kind of a screw. If you go back a little to the basics of science, a wedge is one of the six simple machines.
As it is forced inside an object, it exerts an outwards force on the sides, thus splitting the object with less effort. Wedges are used in the splitting of logs and wood to date in the form of axes, chisels, and other tools
A screw behaves the same way with MDF, and its wood fiber structure compounds the splitting problem.
But it is the edges of MDF that are worrisome when it comes to screws. Not to mean that the face grain is immune to splitting. Just not as common.
It has everything to do with how the fibers are layered and aligned during the manufacture of MDF. The arrangement is what makes the edges more vulnerable to splitting than the face grain.
MDF being very versatile, is used for a variety of projects. And while there are many non-screw options for joining parts, a screw is always preferred for certain applications.
If, for example, making cabinets with doors or drawers, screws come in handy for affixing hinges, brackets, drawer slides, etc. How do you do it without potentially splitting your workpiece?
Don’t throw in the towel yet. You can still drive screws into the MDF face or edge with great success, provided you choose the best screws for MDF and begin with a pilot hole.
What Are The Best Screws For MDF?
There are many different screws out there in various shapes, sizes, materials, and finishes. Some screws are designed for MDF. You do not need a special screw for MDF, though they are good to have. You can even use a chipboard screw.
The best screws for MDF are straight-shanked, double the length of the MDF, with either a flat or pan head.
Let’s dive into the reasons why.
5 Things To Consider When Choosing a Screw For MDF
Any screw that fits the following criteria will work fine with MDF:
1. Shank
We had already established that a tipped shank is an absolute no for MDF. Go for straight shanked screws instead.
2. Length
Screws should be at least twice the length of thickness of the MDF and at least more than half the total width. Longer screws also mean more threads which translates to a much more secure grip.
3. Thread Depth
Medium and coarse grain screws are the best for MDF. The threads dig much deeper into the fibers securing the MDF more tightly. Avoid fine-grain screws like drywall screws.
4. Head
There are multiple head styles to choose from though it isn’t all that significant aspect. Nonetheless, a flat head screw or pan head screw are most popular with MDF.
5. Gauge
#8 or #10 gauge screws are ok for MDF though it depends on the thickness of the boards at hand. You may need to go some gauges up for a very thick board. But remember, the wider the screws, the higher the chances of cracking.
How Well Do Screws Hold In MDF?
Having a clear picture of the perfect screws for MDF, the ultimate concern now is how they will hold up. You’d hate to go through so much trouble only for things to come apart.
How secure are screws in MDF? Screws on MDF are very secure. As long as you use the appropriate screws and the right approach, you shouldn’t experience any problems, especially in the face of MDF.
The edges are the problematic areas. But even these can be handled well with a few hacks. Read on to learn experts’ best-kept secrets to screw on MDF.
7 Bonus Tips For Using Screws In MDF
Driving screws into MDF professionally takes more than just having the right set of screws. You must employ a few more tricks to drastically lower the chances of the MDF splitting and create a strong joint that holds up to weight and movement. Here we go.
1. Always Begin With A Pilot Hole
Failing to begin with a pilot hole before driving screws in MDF is setting yourself up for failure. A pilot hole is the most critical thing, next to getting the screw right, and cannot be overemphasized.
You must drill an appropriately sized hole where you want the screw positioned. To get the right fit for the screws, use a drill bit that is as thick as the screw’s shank.
The best bit is that which is a tad bit smaller than the diameter of the screw. A bit that is at least 80 percent the diameter of the screw is ok. 90% is even better.
You must aim at getting the size right because if you make the hole size too wide, it will be completely useless. Consequently, the screw will wobble inside instead of biting into the walls.
There could be potential swelling and cracking if the pilot hole is too small as well. You may not see the crack if it doesn’t go all the way to the surface, but it will undoubtedly negatively impact the joint’s stability in the future.
Also, remember the diameter of the screw is measured from the inside of the threads, not the entire width from the outside. The threads are excluded.
Another point to consider with a pilot hole beside the width is the depth. Ensure the hole is as deep as the height of the screw or even deeper by a few millimeters to be on the safe side.
If the pilot hole is only as deep as part of the screw, the remaining bit may split the MDF when the screw is driven all the way.
Lastly, use a very sharp drill for clean holes.
2. Choose Your MDF Carefully
The quality of the MDF is critical and affects the stability of the screws. If you haven’t bought your MDF yet, the density is worth considering.
The standard density range for MDF is between 0.022 lb/in³ and 0.029 lb/in³. Anything within the range or even higher is excellent to work with.
The higher the density, the stronger the MDF and the fewer chances to split. Screws hold up much better too.
Now, it’s normal to be attracted to lower price tags, you know to save a dollar or two where you can. But when purchasing MDF, avoid the cheapest ones. They are likely of low quality and less dense.
3. Position Screws A Reasonable Distance From The Edges
You want to avoid getting screws too close to the edges of the MDF where it’s vulnerable to splitting. The border is the weakest point on an MDF board, the same as solid wood.
Your best bet is positioning the screw at least 70mm or 3″ in. They’ll be enough support on all the sides
4. Maintain A Straight Line
Accuracy is essential when driving your screw in MDF, more so close to the edges. Try as much as possible to keep a straight course.
Wandering off course or inclining means you will be moving at an angle that can cause bulging, splitting, or tearing out of the other side.
By measuring and marking the true center of the MDF board, you are sure you start at a central position and align to it when drilling. Use a ruling device to measure across, then divide that value by two to get the center.
5. Use A Dowel And Glue
A dowel is not a must, but a great alternative if you are looking for some real reinforcement for your screws. Because a dowel is actual wood, it provides a meatier perimeter for the screws to have something better to hold onto as opposed to the fibers.
You can also use a dowel to correct the mistake of an oversized pilot hole. The dowel is glued into the hole, and then the screw goes through it.
Some woodworkers also put a dollop of epoxy glue into the pilot hole right before driving in the screws. Again this is optional but if you want to back up the screw with a bit of strength, go for it.
6. Avoid Excessive Tightening Of Screws
A rickety structure is a sign of a bad job. Apprentices strive to tighten their screws all the way, sometimes a bit too much.
Overtightening of screws is not a welcome move when working with MDF. Unlike solid wood, the packed fibers within MDF are relatively weak, so it’s easy to go over the limits.
Tightening screws too much could easily strip out the screw hole leaving the threads with barely anything to hold onto. And because you might just do this subconsciously, it is best to take measures to avoid going overboard with the tightening.
First, you may opt for a countersink bit. As the name suggests, a countersink bit stops screws from sinking deeper than you want. It creates a beveled edge for the screw head to lay nicely and level to the surface.
As a bonus, it is also neat, and professional-looking as the screws don’t appear obvious. When you over tighten screws without a countersink bit, the screw head goes deeper into the MDF as long as you keep going.
Driving the screw beyond the length of the pilot hole makes it force its way through the MDF. Because there’s no more room to accommodate the screw, it is likely to cause splitting.
In addition, you must countersink both sides of the hole, and here’s why. The top accommodates the screw head, but what of the bottom?
The bottom sink accommodates the fibers building up from the screw entering the bottom/adjacent/second MDF component. We hope this makes sense
Another solution to tension issues is to use the clutch on your drill if it has one. By setting the clutch to the lowest value, the drill will automatically slip or disengage when the value is reached, and you try to surpass it.
There’s no way to exceed the limit even if you are not paying attention.
7. Clamp The Sides
And our last but not least, and probably most ingenious tip, is to clamp the sides of the workpiece before drilling the edges. You can use ordinary clamps or hand screws.
When the sides of the board are clamped, it becomes nearly impossible for the MDF to split. A counterforce blocks the force exerted by the screw outwards from the clamps pushing in the opposite direction.
Hopefully, this post has adequately addressed the question, do screws in MDF work? Screws in MDF work if you use the best tools and approach.
Before we wrap this up, let’s quickly recap the critical points.
Choose narrow, straight shank screws with deep threads, and do not start without a pilot hole. It should be as deep and just as wide as the size of the screw.
Also, ensure at least two to three inches of periphery from where you position the screws. And try as much as possible to keep the drilling centered.
You may bolster up the strength of the screw by anchoring it in a more solid matter using a dowel or epoxy glue.
Most importantly, be gentle as the core of MDF is a little delicate and not like plywood or the tough lumber you are used to. If you meet all these requirements, you can change your entire game.
What can you use instead if you are unsuccessful with screws despite doing everything mentioned? Well, there are a couple of other options for your MDF joints.
You can use glue alone on certain joints. Actually, very few joints, like the Spline, if done well. However, most joints like the butt joint and tongue and groove will not hold up with glue.
You must boost the joint with screws, especially for items that encounter heavy weight or constant movement.
In addition, the edges of MDF are very porous, so the glue just gets sucked in. PVA glue and yellow glue are generally used for woodworking.
Brad nails, a type of long thin nails, may be used in place of screws to join two MDF components and are an effective alternative.
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