Realization about preventing splitting

[Brad_bb]

I've had split out when driving some pocket hole screws in the past in hardwood.  This way of preventing it never really occured to me until I was building this caster shelf unit the other day.  Has everyone else realized this besides me until now?  Is this helpful?  I put a walnut shelf unit together last year and the stock as only 1/2" to 5/8" thick and I was getting some splitting at times.  Had I clamped it, I think I would have prevented it.

Clamping to prevent splitting

[rusticretreater]

Has everyone else realized this besides me until now?

Yes.

[dougtrr2]

I have an old doweling machine I got from my great uncle.  He used it when he worked in a furniture factory.  Clamping stock when drilling holes into the end grain of rails was one of the first tricks he showed me.  

Doug in SW IA

[doc henderson]

Yes, but I usually have to split one first to remember to do it.  

[beenthere]

Wood has very low tension perpendicular to grain, meaning it splits easily. If not drilled, then either the wood will split when a screw is acting like a wedge or the wood fibers need to be compressed when the screw is turned in. So it is a battle between compression or tension properties of the species.
Drilling enough to remove wood first and clamping is the best, which is learned here in this example.

There are other tricks such as running the screw or nail through your hair to get some lubrication (believe it is the lanolin from the hair) to help a lot. Doesn't work for me anymore, but when I had hair it was a big help.

[21incher]

I have had better luck with the Armor Tool, now Bora color coded screws. Less splitting then Kreg screws but hold as good.

[Brad_bb]

Yeah, these were not going into end grain but perpendicular to the grain. It was the recieving board that was splitting, not the shelf rrail I was fastening. Still acts like a wedge splitting if the screw tip is not cutting enough.  Maybe it's the type of screw or the particular wood, or being closer to the edge of the wood.  It was a good lesson for me to learn I had to make a rule to clamp if I want to make sure to prevent splitting.  I just hadn't consciencely really thought about it and how to prevent it.  

[SwampDonkey]

I always drill in hardwood before setting screws, but I use Robertson lo-root screws, that are coated, for fine furniture screws. I never split the wood. I've used them in cherry, birch and maple.

information

https://www.leevalley.com/en-ca/shop/hardware/fasteners/screws/wood-screws/112346-robertson-flat-head-lo-root-screws