Squeezus Posted February 4, 2020 Share Posted February 4, 2020 (edited) So, a month or so ago, I endeavored to build a rig to rate steel. In the process I built a version of the 2.0 rig that used a winch and a crane scale attached to two fixed points on a squat rack to rate steel, but after trying to rate a few bars I decided something had to be changed. With that system, after bending a bar to the requisite 30 degrees, the strain (stretch or deformation) of the bar caused the rating to drop precipitously as soon as I stopped cranking on the winch, making it very difficult for me to maintain consistent ratings. So, I had to figure out a way to eliminate the factor of the strain. This brought me back to the original rating method of using weight on a barbell. Since the weight is hanging, it doesn't matter if the bar stretches a little bit. The weight below (and force exerted by that weight) stays the same. So the question was, how can I use a hanging weight with the crane scale and still have some adjustability without shuffling a bunch of plates around? Answer: Leverage. By using a beam attached to a pivot, I can use a small amount of weight on the end of the beam to create a very large amount of downward force closer to the pivot, and if I make it adjustable, I don't have to vary the weight at all. Also, this allows me to still use a crane scale, which means I don't have to worry about doing any math with the beam or weight, just watch the crane scale. To make it adjustable, I used a piece of unistrut with a special unistrut trolley with a nut welded to it so it can be driven back and forth in the channel using a drill or wrench. I can hang whatever weight I need from the trolley and start rating. So, here are some averages that I came up with on 7" stock (I didn't rate any 6") after doing some rating: CRS: Red Nail - 437 5/16" Batch #1 - 445 5/16" Batch #2 - 485 5/16" Batch #3 - 505 5/16" Batch #4 - 540 Bolts: 5/16" G2 (307A LB Head) - 390 Nails: 70d Big Head (McMaster) - 410 70d Small Head (McMaster) - 430 O1 Drill Rod: 0.25 (McMaster) - 300 0.281 (Speedy Metals) - 310 0.281 (McMaster) - 410 0.290 (McMaster) - 400 0.295 (Speedy Metals) - 430 0.295 (McMaster) - 465 And here's a video of the Krahling 3.0 rig: @Stanley sallee @wobbler Edited February 4, 2020 by Squeezus 14 Quote Link to comment Share on other sites More sharing options...
devinhoo Posted February 4, 2020 Share Posted February 4, 2020 Engineering at it's finest. I bet this same technique could be used to rate grippers too. I don't have a crane scale so when I rate grippers I end up shuffling weights back and forth to my ground scale to weigh them, which is kind of a pain. This rig is more extensive to build, but I'm sure would be easier to operate. Neat-o. Quote Link to comment Share on other sites More sharing options...
wobbler Posted February 4, 2020 Share Posted February 4, 2020 Awesome! I bet there wouldn't be much additional work to use that for rating grippers too. Quote Link to comment Share on other sites More sharing options...
Climber028 Posted February 4, 2020 Share Posted February 4, 2020 I love that due to the scale placement you can replace that 50lb weight with any weight at all and it will still work. I have a tiny concern with how much force you might unintentionally be applying with the drill, and also I would try to make the strap holding the weight as short as possible to reduce oscillations that would alter the force. 2 Quote Link to comment Share on other sites More sharing options...
Squeezus Posted February 4, 2020 Author Share Posted February 4, 2020 5 minutes ago, Climber028 said: I love that due to the scale placement you can replace that 50lb weight with any weight at all and it will still work. I have a tiny concern with how much force you might unintentionally be applying with the drill, and also I would try to make the strap holding the weight as short as possible to reduce oscillations that would alter the force. You're correct, care has to be taken with the drill to make sure that it isn't acting like a wobbly "finger on the scale". After a couple practice nails, I was able to get a feel for how to hold the drill so as to minimize any force imparted to the end of the beam. In addition, I set the drill on the floor several times throughout the process, like when I am measuring the nail angle, which removes any human element from the scale number. Quote Link to comment Share on other sites More sharing options...
Climber028 Posted February 4, 2020 Share Posted February 4, 2020 Use a corded drill, physically attach it to the arm, and then actuate it remotely with a kill switch to the power. Then you don't have to touch the arm at all. Or heck even a small motor and whatever type of controller you want would work great. 3 Quote Link to comment Share on other sites More sharing options...
king crusher Posted February 4, 2020 Share Posted February 4, 2020 This machine will be the new way to bend. We have reverse, du, do, and now MAB. Machine assistance bend. The equivalent of geared powerlifting lol 1 Quote Link to comment Share on other sites More sharing options...
wobbler Posted February 4, 2020 Share Posted February 4, 2020 Yeah might as well make it remote control at this point (even if that just means pulling the battery, zip tie on the trigger, and manually short wires to the battery, or be fancy and add a switch) Quote Link to comment Share on other sites More sharing options...
Climber028 Posted February 4, 2020 Share Posted February 4, 2020 11 minutes ago, king crusher said: This machine will be the new way to bend. We have reverse, du, do, and now MAB. Machine assistance bend. The equivalent of geared powerlifting lol Still not as strong as humans, at least not until it can kink a railroad spike of course. 1 1 Quote Link to comment Share on other sites More sharing options...
Goran Paulinič Posted February 4, 2020 Share Posted February 4, 2020 (edited) Machine is badass. It would be more badass with large wheel (bonus points gained with real or stylized skull in the center of wheel) which can be used instead of machine screwdriver to manually rotate it. You can go full pirate if you casually spin the wheel with one hand between some important conversation and it keeps on swinging doing its job. Edited February 4, 2020 by Goran Paulinič Quote Link to comment Share on other sites More sharing options...
Squeezus Posted February 4, 2020 Author Share Posted February 4, 2020 Just to be clear, I built this so I have the option of getting the Krahling rating on some nails. I have another completely different rating device in the works that will become my primary rating system. I'll share details once I'm happy with the prototype. Quote Link to comment Share on other sites More sharing options...
Bill Piche Posted February 4, 2020 Share Posted February 4, 2020 Simply awesome and innovative as all heck! Quote Link to comment Share on other sites More sharing options...
Horrido Posted February 4, 2020 Share Posted February 4, 2020 Great one and even that you get the same numbers as in the past is really impressive. Hats off! Looking forward to your own rating system and how it works. Quote Link to comment Share on other sites More sharing options...
Danny Young Posted February 4, 2020 Share Posted February 4, 2020 I have some round 5/16" 1144 carbon steel. I've wonder where 7" peice would calibrate at. Quote Link to comment Share on other sites More sharing options...
Tom Flesher Posted February 4, 2020 Share Posted February 4, 2020 2 hours ago, king crusher said: This machine will be the new way to bend. We have reverse, du, do, and now MAB. Machine assistance bend. The equivalent of geared powerlifting lol Brb getting my edgins Quote Link to comment Share on other sites More sharing options...
gripmaniac Posted February 5, 2020 Share Posted February 5, 2020 Just wow! Talk about well thought out - what a brilliant way to go about calibrating bars! 1 Quote Link to comment Share on other sites More sharing options...
Tommy J. Posted February 5, 2020 Share Posted February 5, 2020 (edited) I kind of dig it. small side note to add to comments on the drill. I don’t think the drill, or the weight of it rather, will have any meaningful effect on the rating. The poundage is still measured on the scale that’s chained directly to the steel. So whatever dead weight on the arm doesn’t matter. As long as it’s heavy enough to do the job. The weight on the lever is only used to amplify the leverage at the chains- where the actual measurement takes place. Edited February 5, 2020 by Tommy J. Quote Link to comment Share on other sites More sharing options...
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