# Pocket-holes in Oak Wood? Or will it crack?



## WilkersonsCreations (Mar 2, 2016)

Hello, I'm new here. 

I am currently building some shelves for a client of mine. The shelves are basically boxes made from oak. The thing is, I usually make these boxes/shelves with pine wood. I assemble the whole thing using pocket holes and pocket hole screws (kreg) from the inside. 

As i was drilling the pocket holes in the oak 1x12, i was thinking "the kreg screws might crack this wood since it is so hard", I really don't want to crack this wood, since I paid alot of money for it. So I drove a kreg screw into a scrap piece of oak to see what it would do, and it just cracked it right in half... The piece was very small (about 2" wide and 10" long) so this might of been why it cracked, but it seemed to crack very easily... The piece that the pocket hole is drilled into does not crack, only the receiving board that the pocket holed board is being screwed to cracks. 

Anyone here have experience using kreg screws/holes in oak? (im using red oak) I really need to get this order done, but I am scared to put a screw into the 1x12 peices cause I fear them cracking.

:wallbash:


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## unclefester (Aug 23, 2013)

I gave used pocket holes screws in red oak and not had a problem:
Drill the hole slightly deeper making sure your not going out the other side
Use fine thread screws 
I dip screws in wax first before drilling
Don't over tighten when the screw us set

See if this helps


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## Masterjer (Nov 6, 2012)

Uncle fester has the answer. Use the fine threaded screws for hardwood. Pine likes the coarse threaded screws. I've used pocket holes in oak with no problems.


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## WilkersonsCreations (Mar 2, 2016)

Thanks guys

I'll include a picture below to help you better understand where the pocket holes are. They will be screwing into another piece of 3/4" thick oak, making a 90 degree angle. Is this an angle/position that is prone to cracking? (I've never worked with hardwoods before)


Thanks alot for that wax tip, i'll do that for sure!


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## WilkersonsCreations (Mar 2, 2016)

Here is the picture


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## unclefester (Aug 23, 2013)

Your jig isn't see deep enough. The drill tip should extend through the board into the mate board. The shallow pocket hole is causing the screw to push the wood fibers apart causing the splitting.
Doing a 90 isn't an issue.


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## laxin213 (Jan 25, 2013)

Yes as uncle fester said your jig is not set right. Kreg has a screw selector guide that will tell you the pocket hole depth needed, see below. Also in my experience, you need to use the stop on your drill or driver. You shouldn't slam the heck out of the screw when you drive it home. I set it so it has some resistance and the screw stops, by the chuck skipping. This is more important on softwoods than oak. I think your major problem is not setting your jig correctly.

I have a Milwaukee m12 hex screwdriver for driving home kreg screws. I leave my drill set with the drill bit. This setup works well for me. Also the light weight of the m12 driver feels great after holding it for several hours, and it's small size makes it easy to get in tight areas. Here are some links below that could help you:

Kreg screw selector guide:
https://www.amazon.com/dp/B00GIYLQPK/ref=cm_sw_r_cp_awd_cVU1wbBX05MBF

Milwaukee 2401-20 M12 
https://www.amazon.com/dp/B00VYNEEZO/ref=cm_sw_r_cp_awd_sPU1wbMVDGV1J


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## Toolman50 (Mar 22, 2015)

When using a Kreg jig properly, the holes are pre-drilled, which should eliminate the splitting. 
Kreg screws are sold in two types: Hardwood screws and Softwood screws. Make sure you are using the right screws and your drill depth is set correctly and you should be good to go.


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## WilkersonsCreations (Mar 2, 2016)

Thanks, guys

I have the bit set to 3/4" and the jig set to 3/4"

So should I go back over the pocket holes and make them deeper? Or do I need to drill all new holes?

Wouldn't this make the screw go too deep and the tips would poke through the receiving board? 

Also, the receiving board is what is cracking. Will drilling the pocket holes deeper in this board prevent the recieving board from cracking? 

Should I predrill the receiving board somehow?

Also, what do you guys think about gluing before I drive the screws in? Maybe if the glue was completely dry before I added screws, the wood wouldn't crack?


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## GuitarPhotographer (Jun 26, 2015)

My Kreg jig does not drill through into the receiving piece. And the instructions that came with it don't mention that the hole should penetrate, but that it should be blind.

And I see no easy way to make the pocket deeper without affecting the shoulder depth, i.e., drilling the pocket deeper to allow the drill to penetrate leaves too little wood under the head of the screw.


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## chairfixer (Dec 23, 2015)

Are you using fine thread screws?


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## Novaman (Feb 1, 2016)

I've used pocket holes on oak quite a lot and have yet to split anything. You should never have to predrill, just make sure you have your depth right and you'll have no problems. There should be no hole from the bit going through either.


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## TerryQ (Apr 8, 2014)

If you drive the screws from the outside of a carcass (box) toward the side piece you will be ok. If you drive the screws from the inside of the carcass toward the end grain of a board you can get splitting of the receiving piece.

I've also has splitting problems when using pocket hole screws to make face frames. If you drill the hole too close to the edge of the rail, it may split the end of the style when driving in the screw.


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## WilkersonsCreations (Mar 2, 2016)

TerryQ said:


> If you drive the screws from the outside of a carcass (box) toward the side piece you will be ok. If you drive the screws from the inside of the carcass toward the end grain of a board you can get splitting of the receiving piece.


This is exactly my problem. 

I am drilling from the inside of the carcass connecting two 1x12x64 peices to two 1x12x4 side peices. The end result is a 4" thick hollow box with no visible pocket holes on the outside.


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## TerryQ (Apr 8, 2014)

WilkersonsCreations said:


> This is exactly my problem. I am drilling from the inside of the carcass connecting two 1x12x64 peices to two 1x12x4 side peices. The end result is a 4" thick hollow box with no visible pocket holes on the outside.


Rabbits, dados, glue and clamping would eliminate need for mechanical fasteners. If you want to try the pocket hole screws from the inside you might try the screws that are used with the kreg micro jig, I think they are a #6 diameter instead of their normal sized #8. The heads are a little smaller so the chance of over tightening and driving them too deep is a possibility, so take extra care. I would also use more screws, or use glue to compensate for the lessor holding power of the smaller screws. 

Saying all that, I'm not sure 4 inches is going to give you room to drive the screws from the inside anyway.


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## WilkersonsCreations (Mar 2, 2016)

Thanks for the #6 screw tip. I'll order some of these now. 

Any recomendations on the best non-splitting screws to get? 

And for getting into the narrow 4" opening, I use this drill attachment

I would like to Rabbet, Dado or even box joint this. But the client paid for simple style shelf. If I used rabbet joinery to attach everything, you think I could use glue only? No nails or screws?


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## TerryQ (Apr 8, 2014)

WilkersonsCreations said:


> Thanks for the #6 screw tip. I'll order some of these now. Any recomendations on the best non-splitting screws to get? And for getting into the narrow 4" opening, I use this drill attachment I would like to Rabbet, Dado or even box joint this. But the client paid for simple style shelf. If I used rabbet joinery to attach everything, you think I could use glue only? No nails or screws?


For screws you can use the kreg screws, just use the fine thread #6.

If you are going to make lots of these shelves you may want to invest in the micro block for your jig so you won't have to worry about the screws driving in too far. Should come with skinnier drill bit and collar as well. 

As far as rabbits and glue being adequate, it depends on how you are hanging the shelf. To be safe I would probably dado in one or two or more intermediate pieces since 64 inches is quite a span. I might not be visualizing the end product correctly though, do you have a picture of a finished shelf?


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## WilkersonsCreations (Mar 2, 2016)

TerryQ said:


> For screws you can use the kreg screws, just use the fine thread #6.
> 
> If you are going to make lots of these shelves you may want to invest in the micro block for your jig so you won't have to worry about the screws driving in too far. Should come with skinnier drill bit and collar as well.
> 
> As far as rabbits and glue being adequate, it depends on how you are hanging the shelf. To be safe I would probably dado in one or two or more intermediate pieces since 64 inches is quite a span. I might not be visualizing the end product correctly though, do you have a picture of a finished shelf?


I couldn't find any #6 screws at lowes... and I dont have time to wait for them to be delivered...

I got a pack of the regular fine thread 1 1/4" kreg screws. Hopefully they wont crack... i'll dip them in wax first. Will soy wax work?


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## Novaman (Feb 1, 2016)

I really don't see where there should be concerns about cracking. I just drill the holes and run the screws in. The Kreg screws have a sort of pre-drilling quality to them the way the tip is designed.


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## WilkersonsCreations (Mar 2, 2016)

It seems to be working, kinda. The wood isn't cracking if I drill in and out a few times before going all the way in, and wax the screws, but I can't seem to tighten the screws enough to pull the boards together tight. There is a couple areas I can't use clamps for, since I don't have a 64" clamp.. And those areas are screwed in all the way to point it sounds like it's starting to crack, but the wood never pulls together as tight as I would like... Seems like oak completely depends on clamps for a tight screw bond. I'll definitely stick with pine for now on. 

Thanks for the help guys


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## cps (Jun 21, 2013)

Sometimes fragments from tear out will cause a gap. Try pre-drilling the pocket side just using the screws. You can remove any fragments caused by tear out. Then attach the pieces together.


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## unclefester (Aug 23, 2013)

How tight is the dry fit? Hardwood is less forgiving in butt joints. Best success is having a crisp end cut using a good fine tooth blade.
Kreg makes a clamp that clamps in the pocket hole while you screw in the other side


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## WilkersonsCreations (Mar 2, 2016)

unclefester said:


> How tight is the dry fit? Hardwood is less forgiving in butt joints. Best success is having a crisp end cut using a good fine tooth blade.
> Kreg makes a clamp that clamps in the pocket hole while you screw in the other side
> 
> 
> View attachment 221937


Yeah I need to get a better/thin kerf rip blade. I got some blade burn of some of the pieces as I was cutting. I was able to use a flush trim bit/router to clean pretty much all the burns, but I have one area that I am unable to rout because it's flush with the surface... hard to explain in words. anyway, new problem is I need to remove the last burn on an end grain and sanding doesn't seem to work, it just puts a dent in the wood and the wood seems to be burnt too deep...


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