Is There An Endgrain In Particleboard?

[Tom Watson]

A customer called me today and said that the keeper for a lock that we use for their showcases is screwed into the endgrain of the particleboard. This connection is failing, they say.

I have my own opinion on this but I would like to know if my fellow Wreckers think that there is any directionality to particleboard.

I already understand that this is made under a hot press, which increases the density of the board on its face but, is there any difference in holding power for a screw driven through the face v. the edge?

I'm talking about a screw that goes into the board for 1-1/4".

Glad to hear an opinion.

tjwatson1ATcomcastDOTnet (real email)

(webpage)

[Ed Clarke]

[snip]

You DO have to use special screws in particle board. Take a look at this first, then do a search on particle board in their search bar.

hate particle board - mdf/hdf/osb - all glue with a waste material binder. Only place I use it is for the extension table on my unisaw and on a couple of sliding tables for power tools.

[skeezics]

Wellll i gots my own thoughts on PB as well but we wont go into that! lol.. :-]> as far as i can tell its all end grain! however screws do seem to hold better into the face side. you absolutely must pre bore it though as i'm sure you are aware. and glue the heel outta it too ! is there some way to incorporate real wood into the mix where the lock is? just a thought.

skeez

[Will]

I have see the presses that make this stuff and have learned the manufacturing process. DAMW!

These boards are actually (usually) multi layered - again most boards are 4 to 6 layers. (Fiber, resin, fiber, resin, fiber,resin, fiber - then cook in the press - cookie sheet or continuous roller style) There is "some orientation" of the fibers in particle board and fiber board. Again - depends on the board and the manufacturer. Been through a lot of plants... Never saw any that weren't like this - but somebody always knows more. :-)

There is a normally a finer layer of fibers on the outside (face) of the board (except -- I think -- on the very coarsest boards - the Oriented Strand Board -- OSB style). My own experience is that screws hold better on the face - not the ends. probably this is due to the press action and a greater compression 90 deg. to the face of the board.

Next time you are in the lumber yard take a close look at the construction of the different styles -- you should be able to see the layers. MDF is usually the easiest to see the layering.

Just wear a dust mask when you cut that crud.

Tom Wats> A customer called me today and said that the keeper for a lock that we

[Chuck Hoffman]

There is no "grain" to particleboard, end or otherwise. It is made up of small, randomly oriented fragments of wood fiber (basically sawdust) in a resin binder. Threaded fasteners frequently fail in particleboard because there is little structural integrity to the material.

The fix for your particular problem is to bore out the failed screw hole, glue in a hardwood dowel, drill a pilot hole and reinstall the screw.

[Lawrence L'Hote]

...or maybe, glue the dowel at right angles to the screw. A screw into the endgrain of most any wood is a weak attachment. This is a picture of something I did last summer rebuilding a desk. The pine serves as a substrate for a quarter inch oak plywood top glued to the substrate. I drilled the holes 5/8" with a Forstner bit and used hardwood dowels. Also I used pocket screws predrilled through the oak trim on the desk edge. The screw holes were then plugged with matching oak. Of course, I realize that my suggestion just might not be feasible for this particular problem.

[Paul Kierstead]

Well, particle board can refer to a variety of things but..

Considering the considerable difference in paint sucking ability of MDF on its edge vrs. its face, I would have to say it is oriented in some fashion.

For the sheet goods made of coarser chips, it is quite evident from looking at it that the press process orients the chips "flat"; this would indeed make it directional. This is probably true for MDF as well, it is just harder to observe; anything composite made of non-symmetrical bits would tend to exhibit this I would think.

OTOH, man-made materials is certainly not my field of expertise.

PK

[Dave Balderstone]

Randomly oriented in three dimensions?

I think not.

They may be randomly oriented in the horizontal plane but they are oriented horizontally in layers. Therefore, there is end grain.

As Paul sez, compare the paint sucking ability of edge vs face.

djb

[BobK207]

binder.

Particle board, MDF & OSB are all quite different products.; they all have their uses. MDF has decent strength, machines well & accepts paint well. It is not particle board but it isn't furniture grade hardwood either.

Particle board is just that; made of wood particles; not much better than coarse sawdust.

MDF is made from wood fibers that are generated by breaking down wood chemically to the fiber level.

OSB is made from wood species that cannot be "peeled"; but can chipped or flaked.

That said; the faces of all particle board, MDF & OSB are denser than the edges, thus generating "end grain" or directionality behavior.

Source of info:

f2f discussion with APA wood specialists

cheers Bob

[Mark and Kim Smith]

[Unisaw A100]

walking by, sees a pot, sees the stick sticky from it, tempted to stir but realizes, not enough time in the day and moves along...

Burma Shave

UA100

[Phisherman]

[Andy Dingley]

If we accept modern as "last 100 years", then we've just missed the timeslot for a designer you'd surely agree was better than Stickley - Harvey Ellis. Looking at any of the "Gustav Stickley" designs the good stuff is Ellis', the lumpy ugly ones are Gustavs. Sadly the rarity of their sales was such that Gustav's are now rarer and more valuable.

Although I do accept your general point, it's also a little unfair to some of the less well-known but equally skilled designers of recent years - some of whom are working very much in Stickley's (or Ellis') style itself.

[Tom Watson]

Physical Properties* Density 45 lbs/cu ft Internal Bond 80 psi Modulus of Rupture 1900 psii Modulus of Elasticity 340,000 psi Screw Holding - Face 235 lbs Screw Holding - Edge 180 lbs

*Physical properties tested by using method ASTM D 1037-91

(real email) (webpage)

[Andy Dingley]

Some is pressed, some is made through a roller process (usually lower grades). The pressed stuff has faces and four edges, the rolled stuff has variation between warp and weft edges as well.

MDF will take screws in an edge, if you pre-drill and use a parallel threaded woodscrew (not a drywall or self-tapper). Chipboard (particleboard) is garbage however you treat it.

[Mike Marlow]

Translation - termite shit.

[dzine]

A 1" board lstarts as a 24" mat of fibre pulp before compression so i suggest if there is an endgrain it is the edge. So someone has put a screw into the edge of a board. As to fixing the break up of said board i use superglue thin and cramp flat before setting. The hole invariable closes and insert screw again.

[Robatoy]

[snipperectomy]

Absolutely.

When I used to assemble case-goods, I used a 1/8" bradpoint bit in an air-drill and then used a 2" #8 'LOWROOT' screw. Aggressive threads, but skinny root. The drill bit is bigger than the root of the screw, even then, the shit will split sometimes. Its 'end-grain' is like a stack of wafers.... easily split apart.

The 'face grain', however, has the added benefit of there being much more surrounding material to allow some lateral pressure from the cutting screw threads. The particles are finer on the surface as well. But don't count on that near the edge... for obvious reasons.

Let's face it... the only redeeming factor is that PB is flat and cheap. A great material to use as a substrate for veneers and laminates and even melamine. A client of mine cut 2' x 2' panels from PB and 'tiled' his workshop floor with them... he edgebanded each tile with 3/8" oak strips. 3 coats of Fabulon and it looks like cork. A great, cheap floor.

..ran out of tea...gone

0?0

Rob

[dzine]

OK an anology forthwith. Like putting a screw into the front of book or into the side (between pages). Compressed board=paper - so neat.

[TWS]

Tom, your data confirms my intuition but I'm surprised there isn't a bigger difference in holding power.

TWS