OMG .... The Dreaded Brown Stuff ...

[Bluechip]

Hi Troops

I've been sorting my junk out and I've found a whole load of 3mm R.H. S.S Pozi screws of various lengths.

I thought they were wood-screws 'cos they all look the same. But ..  some almost certain to be self-tappers.

Found this:

https://www.accu.co.uk/p/149-what-is-the-difference-between-self-tapping-screws-wood-screws-chipboard-screws

This infers that the pitch would be different but if they are, without shoving the damn things on my uScope, I can't see any significant difference.

Question:  For our purposes, does it matter much ??

EDIT ie. Using a self-tapper as a wood-screw ??

D.

[crueby]

A lot of times the main difference between a wood and metal tapper is the shape at the very tip and the shape of the head. Metal ones typically have a fatter point, which could be harder to start without splitting wood, and the head on metal ones is a pan head vs countersink on wood. Though, I have ones meant for plywood that have a pan head that is a lot wider than the ones meant for metal. Subtle differences, and if you already have the 'wrong' type they will work fine

[Bluechip]

Cheers Chris   

All the ones I have seem to have the same round head and come to a sharp point.

But:  From the Accuscrews link ...

Stainless steel self tapping screws can also be used in woodwork, but their threads are not specialised for this purpose.

For some reason I missed that before, so ...

They are all now promoted to the rank of WOOD-SCREW !!!   

Can't spend all day fooling with the things.

D.

[Jasonb]

I usually find the core diameter of a self tapper is a bigger percentage of the overall diameter than a typical modern wood screw so just watch out for them splitting the wood if used near and edge or end

[steamer]

And as usual, always try a "new" screw on a piece of scrap first to see if its going to split and if you need to change your pilot drill size...

Dave

[Lew Hartswick]

Then there is the problem of words / language.  What is the definition of "Chipboard" ??  In my "vast experience" :-) of woodworking (some 75 years or so) there is, besides "real" wood, there is "Particle board" (made of sawdust), and "OSB" (oriented strand board) made of fairly large flakes.  ie. nothing labeled as "chipboard".    Oh! I forgot there is that other Mason wood. :-)  I've heard several other words describing it. :-)
   ...lew...

[Jasonb]

Your Particle board is our Chipboard

[crueby]

Your Particle board is our Chipboard

Both known as "crap I won't have in my shop"       Back when I was looking for a builder for the house (many years ago) using chipboard or OSB on the house sheathing and/or flooring was an instant 'nope', NEXT!

[Don1966]

Wood screws come in different thread sizes fine for hardwood and coarse for softwood. Flat base for pocket screws, flat head for recess or countersink.

My two cents
Don

[mcostello]

Now They use it on roofs!

[crueby]

Now They use it on roofs!

Not mine! They used it on a roof 'fix' for my parents house years ago, after it got damp it turned to oatmeal. Had to be redone with the proper exterior grade plywood (and better flashing on the side wall next to it).