Which Screw Has More Power: Big, Medium, or Small?

welcome back to the shop everybody today we're gonna be doing some screwed up experiments which one of these two screws would make more power this large 3 inch diameter screw or this much smaller 1 inch we're gonna find out the answer by testing these four screws I'm working on a project and I need to know what screw will work the best these screws have the same 5 threads per inch which means they will move the same amount with every turn by only changing the diameter of the screw and applying the same amount of torque how does this affect the power so we're gonna build a little rig we're gonna put a meter underneath it we're gonna clamp collect some data and see which one makes more power here's the machine that we're gonna be using to test these screws I started off with two pieces of plate steel that I had here in the shop water jet this interesting design the press going to allow me to control each one of these screws in an environment that we can collect some data from I just undo these four bolts I can spread the two sides apart and then throw in a new nut that's been welded to one of these plates and then it gets sandwiched together and we can exchange screws out rather quickly with this design and then the screw will be pushing down on this electric meter that's going to give us a readout and calculate how much force that we're applying with the same amount of input which will be provided by this torque wrench at 50 and 150 foot-pounds of torque hopefully getting some dramatically different results well be testing the one inch screw and of course the three inch screw and I added a inch and a quarter screw and a two inch screw into this mix just to see if our results are consistent that's how the rig works so there are pros and cons to each one of these diameters let me show you what I mean the screws will have a constant 5 threads per inch so if we take an equal length section of them and unwind the threads you'll see an inclined plane the angle of the plane is determined by the diameter of the screw the large diameter will have a nice taper to it so if I shrunk myself down and wrote a bike up it it'll be a nice gradual ride up the ramp and the small diameter will be a lot shorter and therefore a lot steeper riding my bike up it will be a lot more difficult demonstrates the efficiency of mechanical advantage and the small-angle results in an easier turn now let's add friction to the equations friction comes from how much surface area the screws threaded spindle is in contact with a nut so there will be less friction on the small diameter screw and more friction on the large diameter ultimately it's a test of mechanical advantage versus friction the small screw will have less mechanical advantage but less friction and the large screw will have more mechanical advantage but more friction what will output more force now that we're ready let's do some shop talk talk talk talk shop science shop science all right enough spoon around let's get this test started the first test we'll do is use 50 foot pounds of torque starting with the three-inch diameter screw I'm gonna remove some human air by performing this test three times and taking the average of the three results oh man 2085 that's pathetic very good results here 2074 2135 that test is only resulting in an average output of 2,000 98 pounds of force let's see if our next screw can do better or worse so let's test the two inch screw with 50 foot pounds of force the 2-inch screws average output of force is 3000 222 pounds let's move on to the one inch and a quarter screw third time's the charm applying the same 50 foot pounds of force generates us an average of three thousand three hundred and fifty-two pounds for the one and a quarter inch screw now for the one inch diameter screw the same 50 foot pounds in gets us an average of four thousand eight hundred and forty-seven pounds at these lower input levels we can obviously see that friction is affecting the screw more than mechanical advantage but I'm a little bit curious to see what happens when we crank up the torque to 150 foot-pounds and see how it changes our results let's commence with the three inch screw test at a hundred and fifty foot pounds of input we've got some interesting results a hundred and fifty foot-pounds is giving us an average output of six thousand two hundred and eight pounds so let's move on to the two inch screw we've got an average result of nine thousand sixty pounds the one and a quarter inch screw is up next we finally break into five digits with the screw giving us an average output of twelve thousand three hundred and eighty nine pounds and now the one inch screw oh so that average is thirteen thousand three hundred and ninety eight pounds what I'm seeing is that friction is still playing a huge role almost tripling the previous tests so I have an idea let's change a variable to see if we can reduce some of the friction let's talk about the nut and screw a little bit a typical nut for a screw is as tall as it is wide so this being a three inch this is three inches tall to two inch tall inch and a quarter inch and a quarter this has a one inch it's kind of on a uneven playing field so let's reduce some friction because we know that's the enemy and make all of these one-inch nuts let's see if we can remove some of the friction from the screws and see what kind of results that we can get from that I'm really curious to see by removing up to two-thirds of some of these nuts how much it's really gonna affect the output we could be reducing friction but we're also gonna be increasing the load on the leftover threads will this have a positive or negative effect on the force we've now leveled the playing field with all the nuts being an inch tall so we won't need to replicate the one inch screw test we will start with the 50 foot pounds of force into the three inch screw we've got a slight jump in force output with an average of two thousand three hundred and forty four pounds now for the two inch screw with the one-inch nut the reduced nut on the screw gives us an average output of three and 154 pounds and for the shortened nut on the 1 and a quarter inch screw and this gets us an average of three thousand three hundred and six pounds what we can see here is the nuts that have been reduced by over fifty percent have seen the gain in force I'm actually surprised and I find this quite unexpected let's see if that finding remains consistent when we dial up the force to 150 foot-pounds cut nut on the three inch screw it gives us an average result of six thousand four hundred and twelve pounds the two inch screw is up next and it results in an average of eight thousand four hundred and fifty five pounds and now the one in the quarter inch screw that's its average is twelve thousand seven hundred and eighty four pounds by removing some threads that come into contact with the screw it does change the output force I believe weakening the nut is probably not worth the extra force let's add a grease test to this whole thing to really round off this whole experiment and see what happens fifty foot pounds of input on the three inch screw with this short nut and the grease added coming right up its result is an average of two thousand two hundred and twenty eight pounds bringing it down to the one inch screw with the lubricant and the average is four thousand nine hundred and sixty three pounds these results are pretty similar to the dry thread results we probably didn't see a big difference because the Acme thread is already an efficient low friction thread design so let's jump up the torque to a hundred and fifty foot-pounds of input greased three inch screw still in its one inch nut it gives us six thousand three hundred and thirty nine pounds as its average and finally the one inch greased screw with a hundred and fifty foot-pounds of input [Music] averages out to an astonishing sixteen thousand four hundred and forty-four pounds what I really notice is that the grease really isn't affecting these larger diameters that much which is quite a surprise but on the 1 inch screw there is a huge improvement by adding grease well thank you guys for joining me on this cool little shop science experiment I know I learned a ton and I will be applying all this information on the latest and greatest build that I'm working on so stay tuned for that and I know before you guys go you're gonna ask do I have drawings for this cool little shop press that I built here in the shop for the experiment and yes you guys can go to the fireball to a website and download it for yourself so until then I'll catch you guys on the next one you

Channel: Fireball Tool

Views: 725,520

Keywords: fireball, tool, Fireball tool, Welding, screw, screw test, screw press, custom press, custom screws, most powerful screw, best screw, friction test, shop science, torque wrench, big vs small screw, threads per inch, giant screw, twist test, screw 101, how to lathe threads, threads on lathe, best screw for the job, strongest screw, best screw design, screw machine

Id: rGv_UXhNORE

Length: 9min 49sec (589 seconds)

Published: Sun Jul 12 2020