I split a finished guitar body almost in half once not drilling a pilot hole before putting in the final strap button on the end. I will never NOT drill a pilot hole after that :)

I love pilot holes. I have a 8100 cordless Dremel set up with a 1/8" cobalt drill bit and a countersink. I use it almost every single day in my Property Management work. My goal is to prevent wood splitting and prep countersink. I use sharp #10 screws on everything that I can. A 1/8" pilot hole is plenty of hole to prevent wood splitting. However I make larger pre-holes when using extra long screws or lag screws in fence building. Nice video. Keep up the good work!

Another nice comparison test. Please repeat for MDF. I was surprised that no pilot hole did not give somewhat better results. Compressing the wood makes it denser and, I thought, stronger. As for me, I will still drill pilot holes (1) near the end of a piece to prevent splitting, (2) with Philips head screws to prevent mangling the screw head, and (3) with larger screws to make driving easier.

Please. All future results to be expressed in Andys. Perhaps milliAndys would be better as we would not have to bother with decimal points. Thanks for these enlightening tests.

How about trying an in between size pilot hole like 1 or 1.5 mm. Love these test videos.

Thanks for the info! Never really thought about it, as I've always assumed that no pilot would be stronger. Obviously, when it comes to hardwood, I'd always pilot to avoid screws snapping, and with a mind to maybe wanting to ease or remove screws later.

There are four good reasons to drill pilot holes (in certain applications), seeing that the results are so similar. Less chance of the screw snapping if driving into hardwood. If you remove the screw you're left with just a small flat hole and not a bump in the wood. Less chance of the wood splitting. Easier to line up two pieces of wood. Although it does take more time.

I was abit worried about attaching gymnastics rings to pine 3x2, not no more. This video was great. Thanks

Really interesting. Thanks for taking the time to do this Andy.

I'd say the strength differences are pretty much statistically insignificant, other variables such as wood moisture could possibly make up the difference for instance. The main point of pilot holes is preventing splitting and of course making driving the screw in easier :) Good video, thanks.

Fascinating results! You say (at around 7:30) that the 4 X 30 mm Turbo Gold is a self-drilling screw. It is, but when you screw it in, it doesn't eject any material as a drill does - it does help cut a hole but it simply compresses the cut material into the rest of the hole (somewhere) so is different from using a drill to create a pilot hole.

That was a great video. I appreciate you trying to make a fair test and that you recognize that the results are definitive. Wood is very non-uniform, even in the same board. I will continue to use pilot holes for alignment and near the ends of boards without worrying about the strength.

Qué interesantes las pruebas. La conclusion es que, bajo los parámetros de la prueba, no hay gran diferencia en la resistencia del tornillo en poner un orificio piloto o no. Queda para otro estudio ver el impacto de la longitud del tornillo hacia la resistencia (kg/cm) Me encanta la experiementación de tu canal, es de gran UTILIDAD (no siempre se ven este tipo de comparativas), saludos.

Great test Andy,think i'll stick with piloting everything apart from framing! The way I learned seems to be holding true,even with all the advances in dynamics and materials technology!👍👍👍👍👍👍👍👍👍👍👍👍👍👍

Thanks Andy. Great video. I appreciate the effort to test this out!

Never mind pilot holes. They are just to aid screwing, prevent splitting and stop (brass) screws shearing. The important thing is the clearance hole. If you don’t drill that, the two pieces of wood actually push apart.

Useful information, thank you. I rarely wondered about whether or not pilot holes weakened a joint but would have guessed that they did - slightly. Since they are sometimes essential to prevent wood splitting or decorative brass screws from snapping it is reassuring to know that they don't make things significantly weaker.

Good video. If the conclusion is that a pilot hole makes no real difference, then it's not an indication that it's not required, as the pilot hole is there to stop the wood splitting e.g. near an end, to aid alignment e.g. it goes where you want it to go, and to make assembly easier e.g. without needing an impact driver. Normal use of a screw is to fasten two pieces of wood together e.g. using a countersink bit and a pilot drill provides somewhere for the screw head and clearance through the first piece of wood so that the 2nd is pulled into it e.g. No 8 screw uses (Dewalt) 3.2mm drill x 9.5mm countersink head.

Hi Andy, An interesting result, but I normally drill a pilot hole if I am close to the edge of the wood and this is to stop the wood from splitting, so that might give you another idea for a test. Love the tests by the way

Great vid. I'd like to add when screws are driven into wood without a pilot hole surely they are under more stress going in which i'd imagine will weaken the screw.

About 40 years ago I got asked to test the pull out "loads" for screws that had pilot holes vs no pilot holes. The screws were about 35mm long and into (I think) pine and installed by the woodwork lecturer of the local college, the tests were undertaken using a calibrated Denison machine (tensile tester) in the laboratory I was in charge of. Then the pilot holes showed about twice the load-carrying capacity!!! I would think that this video has shown screw design has closed this gap.

Is 2mm the default for any pilot hole or is there some handy "rule of thumb" to use when choosing the size of pilot hole to drill? It's something that seems given by everyone just saying to drill it but I've always wondered actually how big or small I should go.

Very interesting video. Thanks for testing this out

I'd be curious about a demonstration showing how important drill width selection is. I see newbs using overly large drill bits in places not needed (at least looks like it) and at a certain drill size, seems inevitable to be compromising the strength of the connection

Its very interesting to see just how much weight one measly 5x40mm screw can hold up. That's probably more than the weight of my workbench. The idea that one screw could hold that much up is insane. Brb, need to put 4 screws in this pipework boxing in ;)

What would happen drilling different diameter holes? I understand that the pilot holes should be as thick as the centre part of the skrew.

I’d like to see a Test Tuesday of ‘insert nuts’ in MDF vs regular screws. Screwfix 59937 just a couple of quid for 50! I’ve just used some for attaching castors to a cabinet. They feel strong at least!

What a great video!

Thickness of the shank in 4 versus 5 mm screws might make a slight difference. Was going to ask about the oak but your explanation makes sense. But a test in less dense wood that splits easily.... Splitting hairs neh? Pilot holes / pre-drilling can have several reasons (exact spot, easy screwing, brittle brass etc.) but strenght doesn't seem make any real difference. Interesting, learn every day. 👍

Very surprising results. Not what I expected. I can't remember if you have a Kreg pocket hole jig or not. If you do, I would be interested in some PH testing. I have developed 3 different PH techniques. I call them the toe nail PH, the PH super joint, and the cross dowel PH joint. I have done a video on each of these techniques on my channel. I would be interested to see if you would be interested in testing these again the standard PH joint. I suspect they would be much stronger but, I'm not very good at analytics or testing. Let me know if this might be interesting to you for a Tuesday video. Either way, I enjoy your videos and channel. keep it up :

Can you test the Festool and Lamello Knock Down fixings please? Thanks for the intriguing videos.

Was the screw completely submerged in wood or buried into say 3/4 of an inch of wood?

If you have some time to kill, search for “holding power of wood screws”. It’s a paper published by the US Bureau of Standards in 1926. Summary: in softwoods the pilot hole should be around 70% of the root diameter. They didn’t have self-drilling screws in 1926, so that changes things. What’s the root diameter of those screws?

I'd be interested in pilot vs no pilot close to the edge. Including doing the pull test if the wood actually splits.

Firstly once you see it, the image can't be unseen lol. I'm curious whether screws bigger than 5x40mm would also be stronger with a pilot hole. I always thought the reason for drilling a pilot hole was to avoid the surface getting damaged when screwing in as opposed to any strength benefit.

Hi Andy, What would the effect be if you glued the screw hole? Maybe just a bit predictable!

Great tests once again 👍🏻

What about longer screws in masonry that would also go through wooden battens to see of the extra length gives any leverage.

This just confirms that I use way too many screws and overly larger gauge and far too long! I must discipline myself I reckon I could reduce the weight of screws I use in any application by around 1000%.

If I was asked before the test I would have said that the 16mm would probably fail far quicker than before and the other two wouldn't change much. Interesting result.

Do pilot holes actually make wood joints weaker? No. They do not. There.

Very interesting. So I think I'll just use pilot holes where they are needed in future. Do you think using a different size pilot hoke would make much difference? I suspect not.

How can anyone resist “Ta muchly”

Personally I only drill pilots for the screws that DO NOT have those "self cutting" shanks - which looks to be borne out by your results - the self cutting "turbo golds" were made slightly weaker by not cutting / compressing as they were driven, whereas the non self cutting silver crew worked better because they just tend to split and tear the wood if they are driven without a pilot leaving weaker fibres around the shank - the pilot means that the threads bite better because there's no damaged fibres.

The Phantom Knob Drawer strikes again!

MDF and Plywood, what happens there?

Should have "pre-drilled" them pilot holes!😉 (whilst jabbing the trigger on drill!!! )

I've never thought about this.....I use pilot holes to make my life easier or not to split the wood.

Thanks a lot for the video. Interesting tests as usual. Any chance, for the colour deficient people, you could pick different colours for your graphs? It would be really useful - it's the red and greens I (and 1 in 12 men) can't tell apart....maybe a bright green or yellow would work? :) EDIT: Oh, you just said they're ORANGE lines, not RED. I hate being colour blind! GAH: Now you said 4x30 is BROWN??? Is that not what you called orange earlier? EDIT AGAIN: Now you just called it ORANGEY-BROWN :D

Would it make any difference if Phillips screws 😂

You’ve been looking at it too long

I found it quite upsetting to learn that I'm twice the man you are #bloater

Unless it’s a diagram of Hitler’s. 👍🏻🏴󠁧󠁢󠁥󠁮󠁧󠁿🇬🇧

You realise, that when they build the gallows for you; all the maths is done for them - by you!

You’ve been looking at it too long.