protecting MDF screw holes from stripping

Insert a hardwood dowel at right angles to the axis of the screw hole so that the screw will pass through the diameter of the dowel. Glue in place.

A bit tricky for drawer runners in the middle of a big sheet.

Never tried it but I would think about dribbling Ronseal or similar "wood hardener" into the hole, ideally with the sheet horizontal. This penetrates fairly well and sets. Might be worth doing two or three treatments,

OK but it is the best way to do hinges even on a new build to get extra strength. There is normally scope to make new holes in drawer runners into virgin MDF

Don't use a cordless screwdriver. Do it manually, and carefully. If you do strip the threads insert a matchstick with a drop of pva glue or enlarge the hole and use a plastic plug

Sounds like unnecessary work to me. Deal with it if it happens. Mine have been in and out a good few times without a problem

Bearing in mind the relative weakeness of screw threads in MDF I wondered about strengthening the holes whilst I was about it, to guard against future stripping of the thread. Anyone done anything like this? I was wondering about trying to wipe inside the holes already present, with perhaps PVA, or cyanoacrylate glue, or something. Any better ideas?

Cheers Jon N

There are special fixings/gadgets for all these problems, Screwfix has them. White glue in the screwhole works if the load is not too high. Problem arises when you want to take the screw out after glue has set.

In article , jkn writes snip

Snip I drip in a few drops of thin cyano' (not enough to fill the hole). The thin stuff will harden the surrounding mdf. When it comes to re- assembling try to get the screw started into the original threads so that you are not cutting a new thread.

I have had some success in repairing damaged holes by using ordinary plastic wall plugs. Enlarge the hole sufficiently to be able to get a plug in - might need to be tapped with a hammer. Maybe also coat it in glue.

Obviously that is only acceptable where the area around the screw hole will end up covered by something.

rom an MDF wardrobe prior to painting shortly. For 'domestic acceptibility' reasons I can see me having to refit and re-remove some of these more than once on the path to a beautiful painted finish...

about strengthening the holes whilst I was about it, to guard against futu re stripping of the thread. Anyone done anything like this? I was wondering about trying to wipe inside the holes already present, with perhaps PVA, o r cyanoacrylate glue, or something. Any better ideas?

Fit more fixings. Or get some decent furniture to begin with. Sorry, I hate mdf, I used it once.

In message , Chris Holford writes

Given that the original holes on kitchen furniture are precisely drilled and the screws are specially designed, I really don't know what this thread is about. Something that might happen if you tighten the screw on max torque? Why would you do that?

Railway sleepers more your style?

that's because they're drilled in the 2 pieces separately. Once rails are assembled to carcass, further holes can be added to the 2 without need for a template.

Standard pointed coarse thread screws do add less strength per screw, but still add significant strength and can greatly increase rail load capacity.

I presume the OP wants some weak furniture to survive multiple reassemblies.

NT

no

NT

assembled to carcass, further holes can be added to the 2 without need for a template.

still add significant strength and can greatly increase rail load capacity .

Any manufacturer worth his salt would have multi-hole boring machines or po int to point machines to drill all the holes in one pass.

Standard 'pointy' screws aren't much good if screwing into the face of 18mm chipboard or mdf (or even 15mm if you are shopping at the bottom of the ma rket). Euro screws in a pre-drilled 5mm hole or k.d fittings are generally used.

IME kitchen units can be knocked down and re-assembled any number of times. I had my 25 year old MFI 1000mm base unit in and out several times recently (don't ask), and all the fixings went back as good as new.

They work fine for me. Just don't expect as much pullout resistance each as fat screws or other chipboard fixings. I've toughened chipboard furniture up quite well with extra fixings.

Normally chipboard, not mdf. And I certainly wouldnt say there's absolutely nothing wrong with it. Its built down to price, doesn't last well, can't cope with water, can't cope with anything heavier than bedding, etc.

The one time I used MDF it proved ill equipped to deal with a decade of normal household life.

Its chipboard, with all the downsides of chip. Real wood furniture looks much better, is far more durable, and if damaged far more repairable. I see little sense paying a bit less for something that will look crap in 10 or 20 years.

NT

I'd better move that dinner service of mine then. After 25 years on the shelf of a Hygena wall unit, it's probably going to come crashing down quite soon.

A good tip is to always turn them anti-clockwise, until you feel the click where the thread starts, then start to screw in. It saves the screw cutting a fresh thread, which weakens it. It works on most things which cit their own thread, including steel sheet using self tapers.