How to Screw into MDF without Splitting? 5 Easy Steps

Medium-density fiberboard is surely one of the most versatile wood materials. You can use it for almost all sorts of wood applications. It comes with some great characteristics except for one drawback. That is the material tends to split when you drive the screw on its edge. Thus, many users ask how to screw into MDF without splitting.

Well, since the MDF tends to split while drilling or driving screws, the process has to be a bit tricky. Unlike the method of straight screwing, MDF first requires a pilot hole to make itself prepared for being screwed. Moreover, screw types also decide the proper screwing of MDF without splits.

So, surely, knowing this much is not enough to achieve the desired result. Hence, let us guide you through the entire process. Thus, bear with us till the end.

1Choose the correct screw type: Use screws with a coarse thread and a flat or pan head.
2Choose the correct drill bit size: The drill bit should be slightly smaller than the diameter of the screw shank.
3Mark the location: Use a pencil or marker to mark the location where you want to screw.
4Pre-drill a pilot hole: Use the drill bit to pre-drill a pilot hole in the marked location. The depth of the hole should be slightly shorter than the length of the screw.
5Apply wood glue (optional): Apply a small amount of wood glue to the pilot hole before inserting the screw. This can help to reinforce the connection and prevent splitting.
6Insert the screw: Insert the screw into the pilot hole and turn it clockwise until it is snug but not overtightened.
7Repeat: Repeat steps 3-6 for any additional screws.
8Wipe away excess glue (optional): If you used wood glue, wipe away any excess glue that squeezes out of the pilot hole.
9Allow the glue to dry (optional): If you used wood glue, allow it to dry completely before using or moving the MDF piece.

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Why MDF Splits When You Screw?

Yes, this is the first thing you should know as information is power. Also, this knowledge will lead you to obtain the process properly. However, it is always the characteristics and density of the material that induces such splitting.

Medium Density Fiberwood is generally made by breaking down the residuals of softwood and hardwood into wood fibers. The fibers are then first compressed and later glued together to create a dense material. Then when the glue cures, the material is pressed giving the shape of a board.

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The material is also smooth and you can both paint on it or cover it with veneers. However, what is more important to know is the density of the MDF. The lower the material density, the higher the chance that the screw will lead the material to split.

It is because lower-density MDF contains loose and tiny fibers. Therefore, when you try to drive the screw in a conventional way, the internal components cannot hold on to the fibers together due to lack of strength. As a result, MDF starts to split.

Again, if the density of MDF is too high, then there are tendencies for bulging of the MDF to occur. That is why make sure that you are using a quality MDF.

Moreover, as we mentioned earlier, type of the screw can cause such a disaster. If you try to use large screws for driving into the MDF, it will surely split.

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How to Screw into MDF without Splitting – Complete Process

How to Screw into MDF without Splitting

Now that you know the possible reasons for your MDF splitting while screwing, the process should be special. So, let’s get to the guide step-by-step.

Step – 1: Select the Right Screws

This is the very first thing to do. We all know that there are many types of screws available. But unfortunately, not all types will do the work of driving into MDF. Thus, the material requires some special kinds of screws. Therefore, you may ask,

What is the best type of screws to use on MDF?

To lower the possibility of splitting MDF, professionals always suggest using screws that come with a small diameter. Also, make sure the screw is straight-shanked. A regular tapered screw induces splitting while driving through MDF.

Moreover, the screw for this purpose has to be thin and long. However, it should not be large enough. Again, many people opt for wood screws to screw MDF. These screws are not suitable for this purpose at all as they cause tearing of the fibers. Thus, you can use screws that are,

  • MDF screws
  • Trim head screws
  • Type A screws
  • Type AB sheet-metal screws
  • Fully threaded screws
  • Twin Fast screws

So, these are some special types of screws that will help you to drive them into MDF without tearing up any fibers.

Step – 2: Clamping the MDF Sheet

When you are done picking the right screws, it is time you proceed to the next important step. Clamp each side of your MDF sheet. Clamping makes the material stable and sticks to one position. Moreover, this method helps in holding the fibers altogether and does not allow splitting.

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Step – 3: Make a Pilot Hole

Now for this step, the entire procedure is known to be special. Your MDF sheet certainly requires a pilot hole before you drill a screw in it. Drilling a hole before the screw will not allow the fibers to tear most. Hence, it decreases the splitting chance.

However, to pre-drill your MDF make sure you are using the right drill machine for that. It has to be very sharp. A blunt drill machine will encourage the tearing of fibers as it gradually goes into. Thus, you better use a brad point drill for making the pilot hole.

Again, make sure the diameter of the drill is smaller compared to the screw root you have decided to drive. So, when you get the right drill, get started with the process. Make sure you drill a bit deeper into the MDF compared to the length of the screw.

This method will ensure that even if you drive the screw too far accidentally, it will still get into the hole instead of the MDF fibers. So, there will be no splits. However, to get the right measurement of the pilot hole, you can practice on a residual material first.

Step – 4: Countersink Bit the Screw or Use Epoxy

Now, for a better result and clean view, professionals suggest using a countersink bit for making the head of the screw disappear in the wood. It also does not allow the screw head to harm the MDF fibers by creating a force.

Or, you can use epoxy instead. Just drop a little bit of epoxy into the pilot hole before inserting the screw. The epoxy helps join the board strongly securing the screw. Hence, the split risk also lessens.

Step – 5: Drive the Screw

When you are done with all the previous steps, it is finally time to drive the right screw into the pilot hole. So, with the proper drill drive the screw with the countersink bit into the hole and the task is complete.

However, there are some tips to follow,

  • Know that the fibers are weaker near the edges of MDF. Hence, you should avoid screwing near its edges. Otherwise, it will end up cracking the MDF consequently. Leave around 75mm or 3 inches of space at least from each edge of MDF.
  • Avoid over-tightening the screws while driving into MDF. It results in cracks and breakages. Again, unlike natural timber, the MDF board is less robust. Thus, skilled cabinet makers suggest a firm tightening of the screws.
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Avoid Splitting of MDF While Using a Nail

Using a nail or staple in MDF can also lead to a similar problem of splitting. While nailing, the user often notices the plane parallelly situated to the surface initiates to split the material. Hence, you have to be careful with choosing the right nail for the purpose.

Nonetheless, wire gauge nails or staples with 14 grade or below are considered fine for this purpose. Again, causing of splits also depends on the amount of pressure you are delivering while nailing. Only providing the right amount of pressure can save you from a splitting incident.

Moreover, you also need to maintain the right angle while driving the nail. Otherwise, there are possibilities that your MDF will start to bend.    

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What is the best way to screw MDF together?

It mostly depends on the MDF size. If you want to join 3/4 inch MDF then use straight shank #8 deck screws with deep threads and with a length of around 1 ½ inches. Also, you can use MDF glues to join MDF. With glue, you do not have to create any holes harming the wood fibers of MDF.

How do you stop MDF from splitting?

The only way to stop your MDF from spitting is to make a pilot hole before screwing. The pilot hole prepares the MDF board for entering a screw in it without hurting the fibers. Again, making your MDF water-resistant by using sealant, stain, or wood varnish will better the quality and resist splits.

What is MDF?

MDF stands for Medium Density Fiberboard. It is a type of engineered wood that is made by breaking down hardwood or softwood residuals into wood fibers and combining them with wax and a resin binder.

Why does MDF split when screwed?

MDF is a composite material that is denser and less flexible than natural wood. This means that if you apply too much force or torque when screwing into MDF, it can cause the material to split or crack.

How can I prevent MDF from splitting when screwing?

To prevent MDF from splitting when screwing, it is important to use the correct type of screw and drill bit. You should also pre-drill a pilot hole to reduce the amount of force required to screw into the MDF.

What type of screws should I use for MDF?

For MDF, it is recommended to use screws with a coarse thread, as they are designed to grip the material more effectively. Additionally, screws with a flat or pan head are preferred over screws with a pointed head.

What size drill bit should I use to pre-drill a pilot hole in MDF?

The size of the drill bit you use to pre-drill a pilot hole in MDF will depend on the size of the screw you are using. As a general rule of thumb, the diameter of the drill bit should be slightly smaller than the diameter of the screw shank.

What is the proper technique for screwing into MDF?

To screw into MDF without splitting, you should first mark the location where you want to screw. Then, use a drill bit to pre-drill a pilot hole. Next, insert the screw into the pilot hole and turn it clockwise until it is snug but not overtightened.

Can I use wood glue to reinforce screws in MDF?

Yes, using wood glue to reinforce screws in MDF can help to prevent the material from splitting or cracking. Apply a small amount of wood glue to the pilot hole before inserting the screw, and wipe away any excess glue that squeezes out.