Do I need to pre-drill holes in particle board for screws?

Question

I'm set to buy a bunch of IKEA furniture, which is notoriously all particle board. (Ah, particle board.) I'd like to strengthen some of the beams of the HOPEN bed with L-brackets from the big-box hardware store of choice.

My question is this: since adding the L-brackets will mean screws, do I need to pre-drill holes into the wood to avoid splitting the particle board? Is there a way to prep these holes without a hand-held power drill? Can I drill the L-brackets in without pre-drilling at all but with great care?

Answer 1

To answer your question: it depends. The larger the screw, the more likely you'll need to pre-drill. If you're installing the screw near the edge, or if the screw is larger than maybe 1/8" wide on the solid part, then I'd pre-drill. To pre-drill, make the hole almost as large as the solid part of the screw (not the threads themselves, they need to have something to bite into). Also, make the hole as deep as the screw minus the size of the bracket. Use some tape on the drill bit to see when to stop.

That said, for your bed, looking at the plans, I think you'll get the most added stability by adding a short piece of 2x2 vertically as a center brace under the metal bar. Check the hardware isle of your HI store to see if you can find an adjustable foot to put on this board, and then attach it via a few screws to the center beam. This is actually a quick way to detect some lower quality beds that use wooden slats from side to side. If the slats have a center brace going to the floor, it's a lower quality bed.

Edit: For clarity, just imagine a table with a 5th leg right in the middle. You have a long span from the headboard to the foot of the bed which will benefit from an extra support directly in the middle. The adjustable legs I'm thinking of screw into the wood leg of a piece of furniture and look something like this (this is a cutaway view, you simply install it into a hole you drill into the bottom of the leg):

Answer 2

As BMitch has said, it depends on the size of the screw, how near you are to the edge, etc.

It also depends on how hard/soft the wood is. The harder the wood, the more you should make a pilot hole near to the diameter of the inner threads. I'd say in hard wood, you should consider using a pilot hole when the inner threads of the screw are 1/8th of an inch, and definitely use one if the inner threads are 3/16ths of an inch.

Softer wood, on the other hand, will be more willing to accommodate a screw significantly larger than the pilot, and using a smaller pilot hole is actually desirable, as it creates more pressure against the screw, and that means higher pull-out strength.

Obviously particle board should be considered a soft wood. If, for example, you use a screw with inner threads that are roughly 1/8th of an inch, then I wouldn't normally use a pilot hole... but I think you probably should use a 1/16th pilot in your case since you are most likely working with thin pieces of wood, and you don't want to risk having the excessive pressure creating visible deformities.

Answer 3

one word. . . GLUE!

Particle board crumbles and nails, screws and staples are almost ridiculous. I just had a particle board kitchen cabinet come falling down because there was nothing holding it up on the wall (with all the heavy china and everything) but a couple of lousy staples. The rest of the cabinet is held together with simple joints (not as angular as dovetails) and GLUE. The glued part is doing quite fine thank you. Why they didn't use glue on the supporting edge I will never know. (The cabinet has been glued now and is going back up!)

To have furniture that is re-assemble-able there must be a female screw receptor sunk into the particle board--preferably glued in. If these fall out, Gorilla glue foams while drying and is really wonderful, while regular carpenters glue is great if you are simply gluing particle board to particle board (watch for plastic coatings).

Also for steamy places, such as cook stoves and bathrooms, particle board and hard board, especially that must support weight, should be painted/finished to prevent the absorption of moisture which will cause it to warp and disassemble.

Answer 4

Particle board pilot holes need to be quite deep, as deep as the screw, according to literature. My screws at moment are quite sharp taper, so making holes a little less than the screw length. Personally, I still want the screw to bite into some grain. I also drop wood glue on toothpick and slide into hole, not much, as I read this is a tried and true method. Finally, a difference with MDF - there is an awesome video of a man who demonstrates MDF requires a much less pilot hole length. Differently than particle board.