I usually find these type of tests interesting but kind of useless until, a few months or so later, I run into an application where it matters and then I think "Darn, I'm glad Matthias ran that test so I don't have to." Thanks for doing the work and keep it up. I really do like these videos.

This is definitely NOT way more than I wanted to hear. This is the kind of experimental hands-on finding-out that we've come to expect from you. More? Yes, please, absolutely.

I would love to see these tests performed in isotropic engineering materials like HDPE, nylon, or acetal plastic. Each plastic with a unique, known yield strength and ultimate strength. I've wondered if the results would be more consistent. Then, I'd also be very interested to see if the results from the engineering materials could be generalized for many different wood species, hardness levels, and grain directions.

I really like how you spent almost half the video explaining the original need for this test. sometimes tests feel....disjointed from reality...so having this one start out with "I'm doin' a thing, and then had a question, and decided to test it to get more info. so this is why I"m yanking screws out and measuring the forces. "love your videos, Matthias."

I'd be quite interested to see the results for nails. Especially those cut or square nails that are supposed to get their hold by bending the fibres down sort of like a feather board

I'm an aerospace engineer whose knowledge of wood is practically limited to things I can remember from your videos. This was really fascinating to me, especially the bit at the end about how little additional threads changed the pull-out force and the negative trades that go along with driving it in the first place. I wish that had been a little more prominent in the video, honestly, to help reinforce it in my brain, but I'm glad you got it in there.

I was assigned a project at work to compare the holding power of screws Vs. rivets and roves in ship building. I searched for weeks for a published standard and mostly just found conflicting numbers published by screw manufacturers. I wasn’t quite at the bottom of the internet (but I could see it from there) when I found a study published by the Montana school of forestry for the construction industry that laid out pull strength of screws in wood. The interesting part of the study was that the moisture content of the wood played a huge factor in the screws holding power.

I'm a software engineer and practically never work with wood, but it's always interesting to watch your videos.

I found this very fascinating about the pilot hole size versus pull-out strength. With no pilot hole being not much stronger than minor thread diameter, I will be putting pilot holes in to prevent splitting even more than I had been. Thank you so much for sharing these strength test videos. Very informative!

As a matter of fact, I think this information is very useful in meaningful and practical ways. Your videos of shown that many practices actually weaken projects. For example, threaded inserts failing before bolts or screws directly screwed in.

i wonder if treating the holes with cyanoacrylate or wood glue will make a difference to the yield strength of the wood?

This is great. I love this kind of testing because it helps me understand what's actually happening, not just the results. That's a far more useful tool to carry around in my head, since it is much more broadly applicable. Thanks, Matthias!

Thanks for taking the time to do these tests. Always interesting.

I think these sort of tests help with a general understanding, or feel, for how materials perform and can thus influence design of personal projects. So thanks Matthias.

Glad to see there's so little difference, because that's something I've always eye balled. I try to make my pilot hole the size of the screw core, or slightly smaller. And I've always prefered screws with less threads because they tend to strip less easilly when I drive them in. Especially in softwood.

Epic video! I don't know about most people in garage shops, but 90% of what I make are more or less experiments in engineering and reduction. But yours are much more comprehensive and structured.

That was fascinating, Matthias. I wonder about this every time I drill a pilot hole. Would be interesting to see you continue these experiments with sheer strength. I'm always wondering how well my drywall screws will hold up to side loads. Great video... Really enjoyed that!

Matthias, please keep doing your thing, it directly adds to the collective of all our living engineering knowledge!

I love the experiments that you run and how you share both your mental and the physical process. Thanks!!!

Thanks for doing these tests. I usually eyeball drills to use for pilot holes. I try and get one the minor diameter or just slightly larger. One slightly larger will be easier to drive and lower the chances of splitting the wood. It's also interesting how the number of screw threads didn't impact pull force that much. Looking forward to seeing you test different fasteners.

I love this kind of testing - you answer all of the questions that I wonder when I build things, but don't want to put in the effort to test. Thank you!

If you think this isn’t interesting, you are dead wrong. I love this sort of stuff! And now I know exactly what drill bit to grab! Thank you so much!

Fascinating results, Matthias! Thanks a bunch for the testing and comparison! 😃 Stay safe there with your family! 🖖😊

Thank you for taking the extra time to film and share the experiments you run.

WOW! Those drywall comparison at the end was interesting AF

I would be interested to see a video on the force required to sheer off a 16d and 8d nails. A lot of times in the trades you nail a cleat to a wall or something you want to move with a crane, and I have always considered a 16d to reliably hold around 200lbs in the sheer direction. Sheer paneling on modern engineered structures usually requires a very specific number of 8d common ("common" being a specific diameter) nails for a reason. Commerical or school wall framing requires 16d common nails for nailing studs, etc. I always prefered to use a smaller diameter nail because there is less splitting especially in dry lumber.

Those wood tapped threads holding it down like a champ! 🙌

Always fascinating experiments when your testing machine comes out. I'm going to have a look for your video on building it.

I LOVE THESE TESTS!!! I also super enjoyed that co-lab you did testing clamps. That was lots of fun! I cant wait for your next experiment!!

These tests are truly useful. In soft wood, I drill 1/64 smaller than the screw's inner diameter. That makes me feel better...

Awesome. Loved this and am looking forward to some sort of series. Thank you for the videos you produce.

I do love it when one of your videos turns up in my feed. Its a rare occasion but i always watch.

You're the best experimenter I've ever come across. Nice work!

I love your testing videos! Thanks ☺

these tests are great - i love seeing the evolution of your rig too! keep up the good stuff, Matthias!

I mainly watch your channel so I can watch your genius in action.

Your contraption is a gift that keeps on giving.

Mattias is a dispeller of unfounded notions, questioning and measuring and clarifying what the rest of us just gloss over with assumptions, presumptions, and "gut feel." As a retired engineer myself, I see the difference between real facts and imagined ones like the difference between bedrock and sandbank.

what i love about these channel is that it is most about the tools and the procedure of making them than the test itself. really loveit

thanks for making this. looking forward to more! I found a load table for pullout force of various sized lag screws years ago, but other screws, too!?! that is so great

Thoroughly interesting, thanks for taking the time to make this !!

I find this all to be very useful. Keep it going Matthias! Thank you

Very interesting, I like these videos. Nobody else would bother, and if they did, they probably wouldn't do it in a way that shows valid results like you.. Thanks for bringing this to us.

The kind of stuff we never learned as trainees over 40 years ago, so very interesting. I'll be using smaller pilot holes from now on...!

As always, very informative content! Thank you. It would be interesting to see the difference between end grain and long grain, and also difference between long grain and long grain (by driving screw radially vs tangentially to the wood rings). And maybe something in between (45 degrees?).

Fantastic testing Matthias, and I appreciate this empirical information!

That was definitely not more that I wanted to hear about it! Thanks a lot for sharing these tests

These tests are very interesting, keep them coming!

Thank you for doing that test, I find your tests extremely helpful and I have actually won arguments with architects and engineers on jobsites using your videos as the only evidence

Great DIY tensile testing machine!

This was perfect, please do more of these.

actually, those tests are really interesting, helps a lot in trying to select which screw to use for which task. I usually go by gut, or try to follow some arbitrary recommendations, which were already proved wrong with your experiment on the thread count (although I suppose they are a bit stronger, but not by enough to be worth it)

I always made my pilot holes the same size as the minor diameter, now I know that a skosh larger won't matter that much. Thanks Matthias!

Thank you for doing this. We need more hard data about this kind of thing.

This was fascinating- thanks for another great video!

Since the beginning of watching all the force tests became a big fan of the screw jacks that are used in case of an emergency to change a tire on gm pickup trucks. Can really move alot with just finger strength.

Pilot hole at minor thread diameter makes sense and easy to do with calipers and a good drill bit set. Thanks for doing this.

Great and eye opening video. Thanks for sharing!

Thanks for doing these tests

I found this beyond interesting, I would love to see more

Great video! It would be interesting to see the effect of adding a washer and torquing the bolt with different values.

Absolutely great and useful information. Thank you sir!

I've been wondering about these exact things. Not kidding. Great video

Great video. I look forward to more tests!

No, not way too much to know about pilot holes. Always wondered what the optimum pilot hole diameter was. Very interesting. This reminds me of Materials Testing class I had is college. Thanks!

Super cool testing. I wonder how pull force is affected if you screw in, then screw out (like making the threads), and then screw in again the same screw and "tight it enough". Also how much pull a regular bolt of same external diameter will hold compared to an screw.

Ohh, there's so much more I'd like to know now (also there wasn't more about pilothole sizes than I wanted to know in the video 😉). How much weaker is a screw into end grain? What about machine screws compared to same outer diameter wood screws? Does tapping the hole change anything? Is there a difference between cutting the thread with a tap and a screw made into a "tap" by filing/grinding teeth into it? (I have accumulated a whole set of the latter over time, because taps create slightly oversize threads compared to screws on purpose, but for wood that's not needed and screws don't "wobble" in a thread cut with another screw)?

These test videos are the best.

You are the living definition of a mad genius. For years you’ve built countless machines, jigs and apparatus that have either proven or disproved a theory utilizing wood or wood products. And after all of this what have we learned? We’ve learned that wood varies in strength and hardware varies in strength. Use your talents to improve products that exist already and help the woodworking community and maybe even make a couple million bucks in the process. I for one would love to hear you’ve built a better mousetrap.

As always cool video Can’t wait for more on this topic

I love CNC kitchen and I love this kind of videos

I would be very interested to see what would happen if you squeezed a drop or two of epoxy into the pilot hole, before screwing the screw in and let it cure overnight, before pulling. Very interesting experiments and test fixtures you come up with.

Very interesting to learn that what I assumed to be correct about pilot hole size is more or less correct. Thank you.

I love this type of content!

Really useful to know. Thanks Matthius

This was not at all more than I ever wanted to know about pilot hole size, but instead very interesting and informative.

This is top notch work. Doesn't matter if it's for wood working screw strength measurements, Matthias' methodology is wonderful. I've seen less quality from a real life rocket engine analysis presentation.

I don't think you're making a lot of money from these test videos... but I'm sure you're having fun doing them... Thank you very much Mathias

Are you telling me I could've been using a single screw to hold my drywall to the ceiling this whole time?!

I really enjoy these tests. Especially the insights into minor pitch and pilot hold etc. Would be great to see same/similar tests on hanger bolts and anchor screws (don’t know if they’re called something different overseas) considering the application claims behind their design. Keep up the great work!

It would be great to see smooth joinery vs. surfaces textured to retain some glue during assembly. I think this would be easiest to test regarding dowels, but I have seen some commentary that box joints are often glue-starved, so I'd be interested to see that sort of test too.

This kind of content is like wood science. I love it.

Actually, exactly what I wanted to know! Not too much! ha ha. I've always wondered about this exact subject, especially the effect of different pilot holes. Great video.

Very useful, thanks for the effort.

Thank you Mr. Wizard!

we want more, this testing is gold :)

I love it, please more!

Thanks. You made a dry subject interesting, as usual.

Another interesting and useful video. I would like to see this repeated for solid softwood, softwood plywood and Baltic birch ply; both into face and edge.

What a coincidence I just rewatched your old video testing drywall screws vs deck and wood screws.

Glad you found the most common failure mode: the wood is collapsing. I suspect that's why no pilot hole showed a slight increase in one of your tests: that pre-loaded the wood fibers and the preload is what resisted failure for a little bit more.

It would be really cool if you could use this to test different types of drywall anchor!

Hello Matthias I like this kind of test very much make more of this test 😊👍👍

I just love this type of stuff; actual knowledge. Too bad it's not a view-winner, but please do note Matthias that even though you would get more viewers talking about vapid stuff like the Kardashians, this is the type of stuff that has real value and is highly appreciated by those who have the appetite for it.

My takeaway was: "do what you expect you should do an use a pilot hole at or just under the minor diameter to ensure secureness and prevent splitting" and potentially "flatter heads may actually be better at preventing pull through"

Very interesting. Thank you for sharing.

That countersink screw's going to have some epic war stories.

I just built a bike camper and was just thinking about this...also sheer strength between two pieces of wood screwed together. Perfect timing! This literally helps me decide how many screws are are actually necessary. I know the screws will usually break if you try to pull em out with a cat's claw or crow bar. So pull strength seems far greater than sheer strength, but I really dont know.

This is really interesting. I've genuinely wondered about pilot hole sizing for a while. It looks like the pilot hole should be the size of inner diameter of the threads, period. More samples would be great!

Very interesting video, thank you!