Very good video mate, tho im pretty sure those scales arent meant to have their range extended like this. While it works, it might break the load cell or other plastic components inside. Besides that, its probably not calibrated properly for loads higher than its range. If the load cell is rated for 500g, its output outside that range will be off by a significang amount. Your last test might actually be caused by a damaged load cell, check it with the steel ball again to see if it works. For future tests consider using a kitchen scale, these usually go up to 2/5 kg and have 1 gram accuracy. Plenty for tourqe testing.

Dynamic torque the commenter was referring to is actually the torque while the shaft is spinning. Your torque tests were done with the coupler stalled against the little scale, this is known as static torque. A simple (and very similar to what you did) test for dynamic torque is a pony brake, you basically just let the lever arm slip on the coupler output so the coupler can actually spin.

if you want to make a 3d print watertight, one of the easiest ways is to just spray on some plastidip. the relatively rough surface of a 3d print makes it really easy for the plastidip to adhere to it. i did this when i made some custom hose adapters and it stayed completely dry on the outside where i sprayed on like 1 or 2 thin layers.

The scale has a maximum because it needs to be able to return to it's original shape. Also when you overload it, it may not change it's resistance linearly in that range.

5:25 It works exactly the other way around, when arm isn't horizontal it's "shorter" so the scale will read more force. Also, "dynamic torque" means torque while output shaft is spinning too.

incredible work! i am looking into implementing this on an rc car.

I've probably had ten sets of those scales, I'm so glad I left that life behind me lol

wait putting the scale to the negatives was actually really smart I don't know if I would've thought of that.

The centrifugal force of the oil being pushed out towards the outside shell as well as it heating up.

fluid couplers are also used in industrial machinery, and they also have blow out plugs in case the load stalls the coupler, you could imagine what happens if left unattended without blowout plugs. it basically becomes a small hydraulic bomb that spews melting hot oil everywhere on failure.

Hi there! Great video! I’d love to see you check the efficiency of the coupler at different loads, (meaning the output is spinning instead of being fixed and you could try to mesure how much energy is making it through the coupler, to figure out the efficiency) Hope to see another one of your videos soon!

You should make an rc tractor trailer with a flatbed to hold metal weights and add the fluid coupler to the motor and simulate torque converter stall and power it would be a good idea but the weed eater is a better idea I say for sure do that one after u figure out the leakage and test the transmission fluid

The layers delaminate probably because as the oil gets hot, it expands ever so slightly... FDM printing layer adhesion is probably never going to be good enough to counteract this. Although I suppose you could try some things like making the housing out of abs and acetone smoothing it (that would ideally create a continuous outer shell) or sintering - although I have heard that this actually makes the part weaker.

Very interesting, thank you for this video

I'm somewhat interested to see how well that sort of fluid coupling works with different viscosities of fluid. Perhaps testing a range of viscosities from water to something thick like gear oil.

You are halarious, plz dont stop making videos !

This coupler reminds me of submersible construction water pumps. They have mineral oil inside them to keep the water out and keep vacuum from forming as it heats and cools over time.

This is super cool! Also slick hair today o7

Another cool video! Thanks. I wonder what would happen if you chilled the oil before use? You could easily put some fins on the sides of the coupler as well; to serve as air cooling.

Very cool. I might have to make one!

something I would love to see would be a different type of dynamic torque test, how the torque delivery changes at different output speeds. it seems like it wont be that different from when its stopped because the main thing that delivers torque for your design is difference in input and output speeds but the g forces may affect its torque output in strange ways.

Drop what your doing. Camden dropped a banger.

I think you should put a small bellows type expansion port on that or maybe a piston with a light spirng to keep the pressure down when the fluid heats up. It would not have to be very big. You could put a large volume like a liter of fluid in a graduated container at low temp. Then heat it to 30C and see how much volume it gains. Then you could calculate how big to make the expansion relief. Perhaps just a thin walled panel of sufficient area on the housing would flex enough to keep most of the fluid inside when it heats up.

Your videos are impressively good considering your sub count

Your videos are always so quiet I have to crank up the volume and then when a different video comes on BOOOM!

To get my FDM project water tight I rubbed it with acetone. That worked really well.

Maybe consider a tube of gasket maker to make your seal between the two halves. Works for my mower 🤷‍♀

nice video! maybe you can print future models in gray? it is kinda hard to see details when the model is all black :) also...maybe you can use a load-cell and a speedometer with an arduino to properly plot the torque and RPM? (just a suggestion) nice video though!

Awesome follow up! I think that the horizontal arm doesn't behave like you think though. The angle between the point of contact and the center of the rotation is actually the interesting angle. You can imagine there is a straight stick between those two points. It would work exactly the same.

Maybe comparing this to a centrifugal clutch and the clutch you made earlier would be interesting. And having a heavier scale would be better, could break the load cell as someone else said.

I've had a custom-made torque converter fitted to a car to improve fuel economy round town - it made a massive difference. To improve the effectiveness of the fluid coupler though you may want to consider designing angled vanes in the turbine and impeller.

You mentioned the expansion as the oil heats up, but another factor could also be the fact that the viscosity decreases as temperature goes up as well. An old mechanic trick for minor oil leaks on cars in hot climates was to just go to a slightly thicker oil, which would often reduce the seepage. I think this could also contribute to the torque falloff you saw at higher temps. I'd be interested to see what happens if you let it cool back down and then test again. That should clarify if the falloff is only related to fluid temperature, or if the small amount of fluid loss might be a contributing factor. Incidentally you were quite right about heat being the major killer of automatic transmissions, but I think for reasons you didn't really cover. If it was just a matter of the fluid being too hot, they would work normally again once cooled. In heat related trans failures, the actual issue is that the oil gets hot enough that it actually changes chemically, vastly increasing the viscosity (essentially it "cooks" for lack of a better term), though these temps are way higher than anything you encountered, above 300F was our rule of thumb for standard ATF. The friction material in the clutch packs then wears excessively as a result of the much higher load due to the thicker fluid, and eventually wears to the point where the clutch packs no longer have sufficient friction to stay locked together (this is the cause of the slippage which is one of the early warning signs of a transmission that's on its way out). I have even seen situations on extremely old vehicles where simply changing the transmission fluid was enough to cause the transmission to fail, as the much thicker fluid was the only thing allowing the clutch packs to grip at all.

It would be interesting to see how much the fluid viscosity changes during a test like this.

Very interesting, especially how much the torque dropped once the oil heated up. Years ago, I tested the stall speed of a car's torque converter with hot fluid (about 180 degrees) vs cool fluid before the trans warmed up (about 90 degrees) because I was curious how the fluid's viscosity would affect the torque converter's slippage. Surprisingly, the stall speed was only about 100 RPM higher with hot fluid than cool fluid (2800 RPM vs 2700 RPM). I would have thought the torque converter would slip much more and be way less efficient when its fluid is so much thinner, but it didn't seem to matter much in my test. Perhaps the fact that a torque converter has a stator unlike your fluid coupler and the obvious difference in the fluid's viscosity stability explains the differing results.

if leakage remains a problem, a possible solution might be in making an inner and outer shell for each half, then gluing them together with jb weld or thin spread of silicone to create a fluid tight membrane. great video, a fun experiment, with tons of possible uses.

If you added a one way clutch and a stator you'd have a mini torque converter. What a cool project!

Awesome video Camden! Do you maybe think the less torque being produced at higher temperature was maybe due to the viscosity of the fluid going down as temperature goes up?

You are awesome

Most modern automatic transmissions actually don't rely on the fluid coupling for high speed opperation, because of the inefficiency and waste heat. Modern torque converters have, in addition to the fluid coupling, a wet clutch which engages once the converter reaches it's synchronous speed, ensuring maximum efficiency and protecting the transmission when hauling loads.

I wonder if you could make a drill/impact use a torque converter to tighten/loosen screws, just a random thought. it could also help with protecting screws and threads from getting stripped/breaking

Make an o-ring groove or a gasket or just silicone it to make a seal to prevent the leaks

7:16 💥 mind blown all this time i didnt need a bigger scale.

Tips for prevent leaking: 1. Try painting the 3d printed parts with epoxy, to prevent/reduce leaking. 2 You can also fill the 3d printed parts packed with grinded/powder salt, and nuke the parts in the microwave fusing the plastic layers together.

if you completely fill the oil and leave no air in there, when you heat it up, the oil will expand and as there is no air pocket to allow for expansion, it will push it self out via any way it can find, in your case, it would be the join of the outer assembly :)

You measured the housing temperature which being plastic, I would assume is MUCH lower than the actual oil temperature.

I would have liked to see how much torque is lost from drill to the ouput shaft

for the overloading problem you can make an armature much longer to reduce the force seen by the scale.

im wondering what would happen if you use low-viscosity grease meant for high temperatures?

The little scales are used a lot with ammo reloading

LETS GOOOOOO

I wonder how close the internal oil temp is to the outside shell, there might be a decent difference?

OMG I have the exact same steel balls! Are yours magnetic too?

10:20 well it makes sense that it seeps out since you filled it full, with the temperature increase the oil will expand and find its way out.

1:20 oh thats the same one i use to weight my trees😂

just coat the housing on resin, if you use the stuff for boats you can seal 3d printed intake pipes and stuff like that for your car (asa)

I'd print it in resin and seal the two haves with rtv gasket maker.

Realistically, when it heats up and loses torque, it's because of the design and the fluid. Modern ATF is fairly thin, and runs fairly hot, but still transfers torque well. In terms of sealing, it needs to be painted with epoxy paint inside if you want to have any hope of it not leaking. FDM prints aren't water tight without it.

Yessss finally

Oil expands when heated. Not a lot but it does expand. If you fill the chamber completely and seal it shut.... leakage

That scale trick sounds weird to me. Usually the limit is set there becouse the sensor is overwelmed and probably becomes very innacurate or it just might break, so the pressure plate probably is designed to physically bottom out when it reaches that kind of weight. Unless its limit is actually 1 kg... for this specific case

Im sure that the fluid leaked out because of it expanding due to the heat, and because it was filled up to the max there was no room to expaned other than escaping. Maybe a little bit of an „air gap“ will prevent it from leaking. Just like the aio‘s pc watercooler🤔

Thos would be awesome scaled down in a small RC drift car or something.

Plastic is also a lot less thermally conductive and has a lot less thermal mass than steel or aluminium so the oil inside was probably a lot hotter. I wonder how easy it would be to cast the parts?

I think your horizontal arm does not what you want it to do. The connector between the horizontal part of the arm and the vertical part would have to be a bearing/revolut joint. In your setup the vertical part of the arm puts a momentum onto the horizontal part of the arm and thus increases the torque. Instead of adding a joint, you could also just use math to get the true torque. Like what you showed at 5:24. Just add a sin() or cos(). Cheers :)

The part of the spheres reminds me of how an automatic variator works. Like tho ones in modern scooters. They have weighted rollers that push a pulley outwards when spinning. The pulley is flat and kinda conical in shape, when it extends for centrifugal force it forces the pulley out and the belt runs on a wider point of the conical pulley, changing the transmission gear. ...I'm not actually explaining to you and my expl sucks i know. I jus didn't remember the name of the contraption.

What's the torque of the drill? Hence efficiency.

Could you do an efficiency test. Also, can you add imperial units.

What was the drill output?

Less gooo

Get a thicker fluid, shock oil from RC cars has a range of thicknesses. They're silicone based and you can get it so thick it's almost wax in nature (too thick for this imo) but vegetable oil is way too thin so you're not going to get as much torque transfer as you could get with a thicker fluid.

Hype is real guys

Cool beans.....

3:38 if anyone wants to read the comment and see him stroke his luscious hair.

I'm still trying to get past printing the owl my printer's sd card came with. Can't get files to it or use it 🤷

Increase in temperature = reduction in viscosity = lower shwar force = lower torque transfer

Making the arm horizontal isn't doing what you think it is. the force at the tip is still rotating around the axis of the fluid coupling, regardless of whether the arm is a straight line to the balance or an L shape or any other shape. It would be better to have the point of rotation level with the top of the scale

Dynamic torque like if the input is at 1000rpm and the output is 500 rpm lower or 200 or 1000. What is the power. Than @ 1500 rpm. Also shock it by violently stoping the output from 500 rpm.

I can understand grams fully well, but I'd appreciate if you would have a caption to translate temp from Celsius to Fahrenheit for Americans such as myself. I understand I could look it up and calculate the values myself, but doing that sort it takes me out of it when I'm trying to enjoy some fun informative content. Those are just my two cents though

not knowing how much time you spent with the previous tests it seems it might have been leaking and you didnt notice at the time and the stain spread looks larger than the volume leaked because wicking spreads it out over a large area

Awesome project, and thanks for sharing. Do you know the torque output of the drill at its various speeds? Would be interesting to compare that against what came out of the coupler and how transmission fluid changes it.

would be cool to coneckt it to as you sead a weed eater enigne probly will need to beath it up a fare bit and make it bigger you could also coneckt it to your gearbox and make a gokart. if you neeed or want more torque from it you could put ep90 in it(ep90 is a heavy oil for axles realy thick) or even make a clutch that coneckts the output with the input to lock the sides together ised for when a vhecle is moving it will lock it together makes it more efishant will need to relece the clutch to change gear thow. good luck with my spelling

It’s leaking oat from the oatside of the hoesing

Is there a way to effectively alter the stall speed of this

negative 360 minus 300 hurts my sensibilities. i would have loved to see 300 minus negative 360. i know its the exact same thing or at least the absolute value is, but subtracting the larger number just feels icky :/

Even actual tyranny fluid heats up and expands. Thats why you have a hot and cold measurement on your cars dip stick. Point is heating up expands the fluid and you have an air tight housing. So it’s pushing fluid out. Easy said than done, But needs a vent.

Given the second pun about the scale I had to tell you that yes basically that's what a scale for apart of weighting stuff is to dont' waste too much of the stuff and in the end dont lose money. Pocket scales are meant for gold bugs or micro electricians or people which uses small stuff, or does experiments like you. I have one for proportioning epoxy resins with hardener, and the tooling gel expecially is always in small batches less than 25g mixed with 8% hardener. The correct proportion does not define the hardening time like in polyester resin for fiberglass but influences the properties of the hardened material. I think drug pushers that use it to carry it around are dumb, since it's an immediate proof of the dealing intentions. Wether for Pablo Escobar as you said, it might be a bit out of sc-🤔

Lol make a DIY load cell

i can only imagine the "people also bought" section for that pocket scale. its actually kind of illegal to own that scale in some cities too! where i live there isn't an explicit law prohibiting owning one, but there is a ton of case law where people have been tried and convicted of intent to distribute narcotics using ONLY the pocket scale as evidence! if you own both the scale AND literally any kind of ziplock bag, you are hosed. if you own little parts bags, you will do serious federal time. its pretty messed up, but that's how it goes here

Pablo Escobar was probably in the truck weigh-station scale range, not the pocket scale range!

increase the blade count... compare several. only fill to 1/3rd.

Was waiting for the drug joke about the scale.. One day kids won't even know who pablo is xD

Try making a paper engine! Lots of fun, but hard to make

500g torque.. not great, not terrible. (get the reference?)

Make a 3D printed rotary engine

Now do it again with ATF :)

You need a stator !!!!

Looks like this thing is acting more like a viscous coupling

Ya vegetable oil is probably not ideal juat some atf or hydraulic fluid would be better because i bet that vegetable oil gets real airaited

0.64Nm? Thats more that a subaru brz wooowowoowowow

I don't think that's what dynamic torque means