Best type of screw to use with MDF

[helotaxi 5,000+ posts]

I either use hurricane nuts (a variety of T-nut that doesn't ****) with machine screws or sheet metal screws to mount speakers. Which I use depends on how big and heavy the driver is. Deck or drywall screws are meant for holding two pieces of wood together and are fine for box construction but they are not meant to hold a flat faced piece of metal to wood. Sheet metal and machine screw are meant for exactly that purpose.

 

[Lonnie 10+ year member]

The coarse thread drywall screws have threads that protrude more than normal, so they grip the MDF better. MDF really have the same structural make-up as normal wood, and as you know it's a ton easier to strip a screw in MDF than a 2x4. Plain wood screws have too narrow and small threads to really hold in MDF(at least the ones I've seen do). You need something with more grip because of that.

At least that's how I justify my use...I've never stripped a coarse thread drywall screw, so I guess it's working ok.

OO ic ic...thank ya and thanks @ the OP for posting this thread. Probably just saved me a lot of frustration and $60 in wood. Didnt save me $3 in wood screws though lol

 

[BumpinKota 10+ year member]

Make sure you pre-drill holes first because the wood might crack if you don't.

Wood WILL crack if you dont.

 

[VWBobby 10+ year member]

MDF crumbles and cracks easily compared to regular wood. The reason it's used in box construction is because its a fairly acoustically dead material. It tends to absorb sound. Since it crumbles and cracks easily, it handles a lot more like drywall than regular wood...There are no long strand fibers like plywood. This is why a lot of guys use drywall screws. They have a type of thread that slices into the MDF/drywall without splitting and chipping it. The thread pitch is finer and the threads protrude more. Its still a great idea to pre-drill any holes in MDF. True Baltic Birch plywood is a much better material to work with, but it is a lot more expensive and hard to find. However the BB is a more rigid material so you can use less of it and still build a box that is just as rigid as MDF. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[RAM_Designs 5,000+ posts]

^^^nice post.

 

[THATpurpleKUSH 5,000+ posts]

Coarse thread drywall screws with a little drill bit to pre-drill with.
1-1/8" for sub mounting and 1-5/8" for box building.

This is what I use, along with Locktite heavy duty construction adhesive (4.50/tube at home depot)

I also use a tool called a screwmate, it pre-drills the hole and countersinks to makes the head flush, and around corners, I go about 1.5-2 inches in to avoid cracking.

 

[texas_av 10+ year member]

has anyone used these?

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Spax MDF screws

 

[RAM_Designs 5,000+ posts]

Looks expensive. Since I have had zero problems with the coarse thread drywall screws, I'll stick with them.

 

[thehardknoxlife 10+ year member]

I just use glue and clamps. If I'm in a hurry I'll use brad nails instead of clamps. If your set on screws, just get the cheapest possible. They're just there to hold till the glue dries. Once the glue dries, you can remove them and fill the holes.