[ljoe1969]

HI

I AM PLANNING ON STARTING CONSTRUCTION ON MY DIY CNC AND I WAS WONDERING WHAT SCREWS TO USE FOR MDF, AND IF I NEED TO MAKE PILOT HOLES IN BOTH MATING PARTS OR JUST THE ONE ON THE OUTSIDE?

[Chombie]

I would pilot hole both parts the edge of mdf might split if you don’t. I would use a deep thread wood screw.

[chuckknigh]

I even predrilled and countersunk for every hole. Easy to do...it only takes a little bit of forethought. I used standard "drywall" screws, but there are specialty screws for drywall if you want to use them.

For right angle connections, there are RTA connectors, including several that use a cam arrangement to make things really good and tight.

-- Chuck Knight

[Mr.Chips]

Wood screws and MDF are not a good combination, because the wood screws are tapered and even with a pilot hole MDF can be prone to split. MDF doesn't have much strength in this area.

As Chuck said "drywall" screws are better. Also place a clamp on the sides of the MDF beside the hole/screw when drilling and installing the scres, this further prevents the MDF from splitting.

Good luck

Hager Hay

[FRAMEDNLV]

I used drywall screws on my particle wood laminate. Make sure you use pilot holes. Clamp first so you don't get pieces between it. Or you might want to counter sink one piece in between to give it a relief for tear out after you drill.

Chris

[krsykes]

What thickness is the MDF? If it's a decent size, I may suggest a different approach and use tapserts.
These are available in both, friction (press) fit and also screw in. They are small brass inserts which I believe are available in M4 - M12 inc. I use a lot of M6 screw types. They need an appropriate sized hole drilled to accept the insert, the press fit ones just push in, while the screw type obviously are screwed in and create their own thread. Most good specialist fastener suppliers should either stock or get them.

Advantage - the tapsert provides a permenant thread in the MDF, while woodscrews can often 'strip' their own thread. Removal of woodscrews can often leave MDF very 'wooly' and loose a secure fixing, while tapserts provide a re-usabel thread.

Disadvantage - requires a larger hole to accept the tapsert, which sometimes may not be available in thinner materials. Worth a try !

[strat]

i used confirmat (think thats right ) screws .... thier made for mdf you have to drill but a really course thread theres some other info on here about em

[tomarnold]

Folks,

Additional info at:

http://www.lungster.com/l/speakers/mdffaq/mdf.html#Q14

and

http://www.woodworkingtips.com/etips/etip0090800sn.html


------------------------------------------------------
Tom

[yukonho]

I have been using screws sold for building decks. They work well and look fine. Yes you need to drill a pilot hole. First choice would be the ones above, if you cant wait, then this is choice #2
co

[tpworks]

Being a carpenter and cabinet maker by trade, I usually purchase all my custom cabinetry screws from Rockler and here is a link to what you are looking for. Although they are designed for particle board they are idealy used for MDF as well.

Tom
http://www.rockler.com/ecom7/product...ferings_id=652

http://www.cabinetmart.com/69-6350C.html


the specs for drilling

http://www.rockler.com/tech/30601-627.pdf

[ger21]

You could save a lot of money buying from somewhere other than Rockler. Try http://www.wwhardware.com .

[ljoe1969]

thanks.

[strat]

another tip i picked up on here was after drilling and threading the screws in remove the screw and put some kind of sealer in the hole (super glue ect) works great for the mdf no probs or splitting using this