Prevent screws from splitting?

[Charles-H]

I'm new to the forum. I'm hoping to be able to get into woodworking more this year and my girlfriend and I are wanting to make some adirondack chairs hopefully in the next few months. I've worked with wood quite a bit over the years but one thing I've never really investigated is why wood ends up splitting and how/what to do to prevent it. It seems to be suggested that the best way to use a screw to bond two pieces of wood together is to drill a pilot hole and a countersink (which I already do), but I guess a step I missed is drilling the top board to the thickness of the screw body? Is there a specialty brill bit that combines the pilot hole, shank hole and countersink? Is that what the taper drill bits that come with the adjustable countersink/counterbores do?

 

[Mike Davis]

Tapered bits will help, but I have to ask... If you are using big box store wood, especially treated wood?

Damp wood will shrink and split around the screws especially if two or more are lined up across the grain.

To be super safe get another drill and use a slightly larger bit in the top board.

 

[Jeff]

Stop using the old style wood screws with a tapered shank and you'll have less problems altogether.

The newer screws have a straight shank and the threads are cut deeper along that shank. The top board is drilled at the same diameter as the screw so it won't bind and the bottom board is drilled slightly less. A countersink in the top board gets the screw head below the surface.

http://www.finewoodworking.com/membership/pdf/8436/011162046.pdf

If you're making Adirondack chairs then bolts/washers/nuts are a better choice to keep it all together.

 

[Charles-H]

Mike, I'm planning on going to one of the specialty wood stores around Charlotte and get wood from them. I used the white wood that Lowes had before and it is just way too soft and dry for purposes like that. But at the same time, I'm not sure what would be a good wood type to use as far as stability, weight bearing, and weather changes aside from oak.

Jeff, I think I understand what you're saying, but I was wondering if there is a combination bit that can be used to drill for the pilot and the shank instead of having to use two different drill bits for one hole. I registered with the fine wood working site but i'm having trouble accessing that page.

 

[Jeff]

Like these? Take your pick.

https://www.homedepot.com/b/Tools-Power-Tool-Accessories-Drill-Bits-Countersink-Bits/N-5yc1vZc8xp

 

[Charles-H]

So the taper shank drills with the countersink take care of the pilot hole and the shank?

 

[mquan01]

Mike, I'm planning on going to one of the specialty wood stores around Charlotte and get wood from them. I used the white wood that Lowes had before and it is just way too soft and dry for purposes like that. But at the same time, I'm not sure what would be a good wood type to use as far as stability, weight bearing, and weather changes aside from oak.

Jeff, I think I understand what you're saying, but I was wondering if there is a combination bit that can be used to drill for the pilot and the shank instead of having to use two different drill bits for one hole. I registered with the fine wood working site but i'm having trouble accessing that page.

G

shoot up to Kyle at Iron Station or Rick up in Moorseville for your wood.


https://www.ncwoodworker.net/forums/content.php?r=81-Sawyers

 

[redknife]

Mike, I'm planning on going to one of the specialty wood stores around Charlotte and get wood from them. I used the white wood that Lowes had before and it is just way too soft and dry for purposes like that. But at the same time, I'm not sure what would be a good wood type to use as far as stability, weight bearing, and weather changes aside from oak.

Jeff, I think I understand what you're saying, but I was wondering if there is a combination bit that can be used to drill for the pilot and the shank instead of having to use two different drill bits for one hole. I registered with the fine wood working site but i'm having trouble accessing that page.

I might not be getting your entire point, but I use these for one-stop countersink:
https://www.amazon.com/Snappy-Brand...id=1517014415&sr=8-5&keywords=Countersink+bit
I don”t use these to prevent splitting, per se. The splitting part is covered already in earlier answers.

 

[Gotcha6]

You may also consider using a pan head screw instead of a countersunk head. These can be countersunk into the wood as well and don't place undue pressure on the sides of the drill hole around the head. A good example of these are the Kreg system screws, although they are not a true pan head, but rather a washer head.

 

[JackLeg]

I'd take a hard look at cypress for your wood choice. It's very easy to work and will stand up well to the weather, finished or unfinished.

I've built a lot of Adirondacks and it's my go to wood every time!

:notworthy: