Always good to test these things. You only have to look at the old windmills and watermills, at least in Europe, to see how wooden gears used to power the economy.
John Harrison, the man who invented the marine chronometer, built a turret clock (for Brocklesby Park, North Lincolnshire) in the 1720s with wooden gears (oak and Lignum vitae) and the clock is still working today. I read about him in the book Longitude. It took a lifetime for him to receive the reward for his invention of the chronometer due to him being a lowly carpenter and they refused to believe he could invent something that everyone else couldn't.
I downloaded your gear template program and I used those gears is a mechanical iris inside a nautical door. It's been over a year, the iris has been opened at least 1,000 times and they are still working perfectly! The gears fit together with such precision that I think they will last a lifetime.
Wooden gears can last a very long time. In fact many early European clockmakers preferred to make their mechanism out of wood because wooden gears do not grind away at one another like metal gear trains do. Also as wood is porous, it can absorb oils and can be self lubricating. Some of these clocks are hundreds of years old and can still keep very accurate time. For example, in 1727,John Harrison who is the inventor of the first marine chronometer built his clock "Precision Pendulum no. 2" At the time it was the most accurate clock in the world keeping time to give or take a second a month. It currently resides in the collection of the Leeds City Museum and its movement is made mainly of wood. Thanks for all of your great videos, Keep up the good work!
Hi Matthias, I like your experimental aproach. In the Netherlands all the old windmills use wooden gears. Alltough they are build as wooden disks with the tooth wedged in to them axialy because the main shafts are all at an angle. I think you might be interested to research this a bit, especially because for every component of the mill a species of wood is selected for its mechanical properties. Two things that I learned from a miller you might want to incoorporate in the power transmission aparatus that you plan to build: 1; use beeswax to grease the gears. This gives a thin but slick coating on the surface. 2; make sure that when you devide the amount of teeth of gear A trough the amount of teeth on gear B you don't get a whole number. This ensures that the same teeth meet occasionally and the ware on your teeth is even. For power distribution this is ideal because you can reduce the play in the gears and thus the noise.
+Owiko7 And did not read that Warning sticker on the window, which says, "No trespassing. Violators will get slapped in the face by a wooden-gear-testing device. Survivors will get spanked by said device."
Hey Matthias, Make a 4 square test rig. This will increase the torque in the drive train and forces on the gears. Then your motor only has to overcome friction loses. Great video! Thanks, Jim
Came back to watch this again. Been considering wooden gears for another project of my own and your results that you have shown here are comforting to me. Thanks mate!
You should have contacted some Dutch windmill conservators they would have told you that they have wooden gears in mills from late medieval times and are still running.
Well, if you know a bit about clocks, you might know that there is an oak tower clock made by John Harrison that has been in continuous use since it was installed the 1720s. I believe the clock has only been stopped occasionally (maybe 3 or 4 times) for maintenance. It was made with brass pivots (hardly no steel was used in the clock due to moisture concerns that may cause rust) running in lignum vitae bearings (a naturally oily tropical wood). The clock needs no lubrication. The wheels were made with 1/4 sawn oak blanks, with sections of teeth inserted into the edges of the blanks, so that all the teeth would run radially for strength. I would think that the Baltic Birch plywood would last an exceptionally long time (perhaps eventually wearing a striped pattern into the mating gear). There are also several weight and spring driven clock kits that are made using BB ply.
Harrison built clocks with wooden gears, a few of which are still in existence today, some 300 years later. He used quarter sawn oak for the disks, and the teeth were cut out of a separate piece and placed in the disk with the grain extending radially to utilize the grain strength. these weren't involute gears, but still lasted exceptionally long.
For tools like your box joint jig, or this test apparatus, wooden gears will last a long time. As speeds or loads increase then the wear will too. I am impressed that the MDF held up so well meshed against the birch.
At one time long ago Ford, Chrysler, Dodge, DeSoto, Willy's, among other automobile manufacturers used pressed wood gears for timing gears in their engines. Oiled composite woods had to be strong to handle it.
Another superb video. I had the feeling that those gears would last until the cows come home. There isn't that much wear in this application. Not to belittle your efforts which I find to be exemplary. I do think that the massive wooden "fan" blade was overkill but then again, I like overkill. Such as when you jump on your finished projects to demonstrate their strength.
Depending on the power consumption you would be willing to use, perhaps a gear driven long time running apparatus for that old barn or wooden gear driven heater for the upcoming winter of some sort. Small scale saw mill comes to mind. I suspect the electric motor will die before the wooden gears fail.
Hmmmm, there is a grain mill near where I live and some of the gears in that are over 100 years old. When I asked the docent about how long the gears last he said it depended on the wood but, that unless one breaks it is left alone. All the wood was white oak, cut to the gear shape after 2 years drying. It would take a LOOOOONG time to wear out the ply in your test, where-as the MDF should wear sooner. The plywood will harden on the edges where-as the MDF will flake away. Heat is the real killer, a faster rig, or more load (producing more heat) I think would result in a higher failure. Wood is an amazing material to use in a low stress low heat rig, like a mill.
MDF is actually very good for noise reduction. On my hand powered, gear boxed, forge blower, there's a plastic gear that's meant to reduce noise between metal gears. I replaced that with an MDF one some, well about two months now. Still works, hasn't chewed up much, and VS the plastic one, there's a considerable noise reduction. One other thing, it was cut on a divider head and a mill (so there's that) and i've dipped the gear's non driving side of the teeth in super glue, the really runny kind used in RC models, to give it a bit more structure. It's a trick i use when i play with geared thingamajigs. Dip the gears in a small disposable tub of super glue and then recut them on the machine. Extra strong gears because the MDF sucks it up.
I have an idea for a long-term test setup. Make a several 1:10 reductions in series, and hook the slowest gear up to your mechanical counter. With enough reduction, the counter would have a rather long duration. Besides, it would be interesting to see the difference in wear across the reduction chain.
Good experiment but I think the wear factor depends on the number of revolutions those gears make and not actually on time. Your ideas and work are nice and helpful as usual. Thanks.
I used baltic birch gears for the reduction on my power hacksaw and even after several hours they also didn't show any wear. I suspect that at low speed these gears will virtually last for ever.
Those are quite durable gears! You could even extend the life of your gears in the design by changing the number of teeth per gear to a non-factorable number of the 2nd gear. As in, offset one of your gears by one tooth. It was have it so the same tooth doesn't meet the spot every time, thus spreading wear across the whole system. Instead of having a failure at (x) number of cycles, it can extend it to (x^n) cycles.
Volvo B series auto engines have a fiber timing gear. They wear, but it takes decades. They also operate at thousands of RPM, with the whole valve train as a load.
Machine that uses wooden gears for power transmission. Already exist. Clocks, windmills (use a different type of gear though, pin and lantern). One engineering maxim on geartrains. Always when possible use a gear with an odd number of teeth and on with a different number of odd or even number teeth. This allows for the maximum number of rotation before the same teeth mesh again. This distributes wear through the whole system
Nice test. Was wondering how this would go myself. Glad to see that for rypical low use projects wood gears will likely last forever. If concerned in a high rpm or continuous use project, seems like a coat of thin penetrating epoxy on the gear teeth would add wear resistance and probably reduce friction.
You should have a look at dutch windmills. They run huge oak wood gears, lubricated with beeswax, and under high load (pumping water) they last for decades.
Well, it all comes down too how well the gears are made, how well they are set up, and how well they are maintained. If the gears are made accurately there will be no excessive contact on the teeth slowing down wear. If the gears are spaced properly, not to tight to enable binding and not so far apart to enable slipping and grinding is another factor. Also whether having the shafts in bearings or not and whether they were lubricated is another factor. And lastly, keep them clean and and in the case of a continuously running machine keep them lubricated.
Good video. I've been thinking of using wooden gears for a few of my Christmas projects for my displays, but wear was a concern. They'd run about 6 hours a day, 7 days a week for a few weeks. Not nearly as fast as what you have here, nor the load, so I might give them a try and see what happens. Keep up the great work.
Just simply try to make a simple mill on the river or stream . Water flows constantly and you don't waste electricity and you can tell the signs of wear after a week or a month of running straight . You can also try a wind mill and a simple wooden gear transmision
Just an obscure comment- typically you don't see 1:1 (or 1:2, 1:3, etc.) gears in anything designed for long life- you want gear numbers without common factors. This way you don't have the same teeth contacting repeatedly- so any flaw (either in the gear at the start or one that occurs as damage or wear) doesn't hammer the same spot on the other gear, but rather is spread out over all of them. Say a bit of casting grit goes through the gears- it might embed in one tooth and then over time destroy the teeth it contacts. It's better to spread the wear over the whole gear set- it'll keep running- rather than beating one tooth to failure. And even wear sounds "even", rather than a spot going "rump rump rump". :) On cars- you notice you don't ever see a 3:1 or 4:1 rear end ratio? Always odd numbers like 3.73, 4:10, 4.11, etc.? So, a 4.10 typically has a 10 tooth pinion and 41 tooth ring- 41 is prime, no common factor with 10. A 4.11 would be 9 & 37... again no common factors. 3:73 comes in at 11 & 41, nothing but primes! Clever automotive geeks! (though I'm sure they copied steam engineers... who copied someone else)
Great test! I am surprised that the MDF did not break down. Baltic birch is a good material for making gears but, aircraft plywood is my favorite material. It is expensive but very strong, stable and nice to work with. Perfect for small, fine pitch gears.
I'd say the biggest problem with using MDF for any moving part that interacts with another, would be seasonal changes. Since depending on the grade of the material the MDF can expand, which if the whole machine was just MDF gears could cause problems since you would have to always have that machine in a temperature controlled areas as to keep it from expanding during seasonal change. Of course I could be over thinking this.
Gears wear mostly when they are torqued as long as you have a system which runs at constant speed you won't really have wear unless the gear surfaces aren't aligned properly or they are oscillating.
Of course the wooden gears and wooden bearings in (Dutch) windmills last many many decades, even when used daily, but they use special kinds of wood like Mispel (mespius germanica, "Groenhart" (bowwood), Demarara, "Pokhout" (Gualacum officinale), Azijnhout (Qeurcus ilex), most likely not Baltic plywood.
i would like to see a re-test with the gears under a more constant resistance/load. I think the wooden board's own momentum after spinning up sort of keeps the gears under less stress than say, if the motor were to spin against a dynamic braking system? Like the way trains use the resistance of the unpowered electric motors to slow down... Surely you know what im referring to? You are Matthias Wandel after all... :)
I would like to see a another test. Use a stronger motor, to put far more torque on the gears. Also use the same type of wood, for the gears. Perhaps 2 tests one with MDF gears and one with plywood, to compare which one is best for gears.
Great video! Off topic, but you should consider installing window wells around your home. The grade of your lawn is right at the bottom of the window, and this can lead to water issues later on.
the only reason for metal gears is size and torque load. you can make a considerably smaller metal gear set to do the same load of work for lighter weight. you also need metal where the input torque load would simply just shear off the teeth of the gears. You maybe have 90rpm there at most with the gears being even. Several electric motors get upwards to 2500-3000rpm. More revolutions more chances for things to break down.
What about testing different loads? Or other testing like torque vs speed? Also I am not surprised it lasted as long as it did. I thought this was going to be at least a multiple month test. Why not put it somewhere out of the way and leave it on until they break, or a few years? Edit: oh I thought you just uploaded this, nope 5 years ago. RU-vid just decided to recommend it now.
i remember stumping onto your website and gear calculator ages ago... i used it for some high school project back then... i think you should make some kind of a drum sender with gear reductor and power it with a drill... to prove if its possible :D an to make it more simple - tilt/rise table instead of the drum :D Great work by the way... one can only enjoy watching your videos and ideas
Wow its amazing how resilient the gears are to wear and I'm sure they would never actually be under any kind of load like this in normal use. Does this make you rethink preferring birch plywood to mdf?
+Joshua Walters I've made one - was worried about it wearing out - no need to worry!! Try googling "wooden clock" and "plans". Lots of plans on the internet, but start with something simple. And start making the escapement as that is the most difficult parts to get right. (And when the escapement is working, the clock is alive and just need some more gears). A clock is a quite simple machine.
+Joshua Walters, + Matthias Wandel. I agree... Matthias, You were looking for a project using gears in power transmission, this would be a good project. You can add lots of gears to do different things than just hours and minutes. Try seconds and Lunar phases to increase the use of wood gears.
Why not make one of those 100% wooden clock mechanisms? They look really nice too, and I'm sure you could find a way to make it accurate and easy to make :)
The harder material will always consumer the softer. For best longevity I would go with the same wood for all mesh parts. That will last longest. Even if you had to option of two pine gears, or an oak and a pine gear. I'm pretty sure the two pine gears would last longer as they would resist destroying each other.
I was thinking the same thing. If you have a harder and a softer material the softer one will get all the wear. This might be useful in a drive train when it is extremely difficult to replace one gear.
+YeCannyDaeThat nope, there's still the same energy applied that needs to be transferred, and same amount of joules will destroy the same amount of material divided by their UTS in a taken finite element. But there is a value before which material is able to completely recover, so if your elements stay in it - your item will idealy be inderstructible. I.e. when you need to triple your speed by means of gears, if you make two gears - a large one and a small one - surfaces of both gear's teeth will be loaded to the point of destruction (even if it's very small and will take weeks or months to become visible). But if you make three or four smaller gears from same amount of material (i.e. instead 60 to 20 teeth you make 30 to 20 to 10 optionally to another 10 for reverse direction) the same force will spread proportionally between bigger summary surface and will wear out slower or not at all.
"Im sure glad i didn't try to use the hand drill to power this" Shots fired! haha. I'm sure Izzy will have a good chuckle when he sees this. As for a woodworking project, what about a pedal car using gears for the kiddo?
Hello Matthias, if You want to endurance test Your gears without using a load and a powerful motor, try to build this rig: two parallel long shafts (torsion bars) having at each end one gear set. Three of the four gears should be fixed on the shafts and the fourth should have a device that can apply an adjustable torque to the shaft . The motor will drive one shaft and will only have to cope with the friction generated by the mechanism. The two gear sets will be in a close loop, circulating a lot more power than your motor can produce, and there is no load needed.
+Vlad Romano -------Hey Vlad, I see you suggested a 4 square test rig also! Sorry, when I made the comment for Mathias to use this I didn't know you had already made that suggestion. Thanks, jimengr
+jimengr Hello Jim, no problem, thanks for your comment. I did not know the English name of this rig, so this serves me well. I work for a European car manufacturer and here it is called "endurance test bench" - in an approximate translation. Main difference is that we put the whole transmission/transaxle in the loop. All the best, Vlad.
you should have put a kill-a-watt on the plug to know how much power you used during this test, just as a reference to how much energy it took to wear it out.
It must be strong, because, before they use them for making windmills There was only wood around. Metal was to expansive I can't understand why people are surprised
I built a wooden clock with gears almost 8 years ago. I'd expect it to continue working for decades if not hundreds of years. I can't see any evidence of wear in my clock gears. They are made from baltic birch plywood. I got the design from Clayton Boyer, the clock is called Simplicity.
Wear is the result of heat. Heat is the result of friction. A lack of lubrication, running them under high speed or high load - or a combination of all of those would cause failure. low speed, low-moderate load applications, particularly with short run time would clearly be no issue.
0:39 I see you using a LOT of rollerskate ball bearings and I can't help my imagination running wild. I imagine you wearing a long brown raincoat, lurking at the playground, waiting for kids on skateboards to roll by so you could kick it away from underneath them and run off with it with an evil laughter :))
If you really want to test the gears you just showed me in this video I think you will need a much higher rpm. You might be able to achieve this with the same motor if you put them on the end of a system of multiple gears.
Ceiling fan motor was good choice for this since they are low speed high torque and can run at high slip with out burning up Wooden geared clocks are another thing that shows that wood gears can be made to last since most of those date back 200 or more years... speaking of wood geared clocks ever going to make one?
once and for all you've proven birch ply is harder than MDF. I think it would've been slightly fairer to run the gears in a matching set and see which one lasts longer- because an MDF gear won't chew into another MDF gear as aggressively as ply wood would. Albeit for the hand-turned jig gears, unless you're name is Schwarzenegger and you get extremely frustrated with it, they shouldn't wear out. (even if they were softer MDF- they're not really "load bearing", or atleast not bearing much of a load). If it was for a driveline of some kind- I'd probably go with a hybrid- the gears which are particularly hard to replace/cut/repair etc. make out of the hardest wood you can justify, and for the mating gears use a high-density MDF. That way, you pick the gear that will wear out to be the easier ones to replace/repair. (in the same way that they use brass for synchro gears, and hardened steel for the drive gears in a manual)
+Roger DC UHMW PE is a good material for some applications, but it will deform under the loads gears impose on each other. It's just not stiff enough. Maybe with large/wide enough teeth it could do the job.On the other hand, it's perfectly workable with wood working gears.
old time windmills have gears of wood. Lumbrication is done with bees wax. solid wood is used. these last for about a century. this test could go on for a while !!
+Gian Carlo Martinelli ; Yes that would be great! And if a wooden chain shows to be too difficult to make (or use), a cardan shaft drive, would be awesome imho. Oh, and for spokes, long & tough fiber vines, made of withy (or so) would be lovely too :) Got time for another project, Matthias? ;)
