Dirtbag pull testing: cheap load cells!
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- Опубліковано 13 вер 2024
- Can you get a pull test rig for $50? Well, it won't be pretty, but yeah! For years I've been trying to find the cheapest, safest, and most transportable pull testing solutions. Here I demonstrate a few that I've got and hopefully start some covos and get some ideas out there. This stuff is pretty simple and affordable if you know how!
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Everything creeps when pull tested, even M16 resin anchors. Sometimes the pull tester itself will be the main source of creep. In the end, everything is a spring, and it shows when you get over 5kN.
Your main source is probably the girth hitched dyneema sling cinching down, then the hanger plate, then the eye bolts. Instead of eye bolts, I'd recommend a yoke and clevis pin. You can DIY one with 3-5mm angle steel.
Yeah lots of springiness going on in these janky rigs! I dunno if you could see but the hanger was bent and the bolt pulled out 5ish mm by the end. But yeah probably the sling was the next biggest source. I'd only ever used metal couplings before and this was my first time with this particular setup. But I'm still always amazed at how well that cheap-ass load cell works!
Would be keen to see how the old bashed in carrot bolts with the plate hold up. Was even considering sending a couple to hownot2 since they don't seem to use them over in the US.
That's an idea. You'd probably have to send a 10mm bit as well. But if you can wait a bit I'll be able to extract some old ones from climbs later this year hopefully!
@@MountainMullet looking forward to it mate!
Your post has seriously made me consider getting a load cell too. I've been having a severe desire to test some of the hardware I've been buying locally. I checked on Taobao (which is China's version of Amazon), and I can get that same nicer 30kN load cell you got there for about NT$10400, which is equivalent to $340 USD (shipped and inc. duties) to me here Taiwan. There are 50kN model costs exactly the same as their 30kN too.
Oh even though Alibaba doesn't show it, the manufacturers & different sellers on Taobao show they've sold hundreds of that particular style of load cell units.
Nice, that's the idea! These things are pretty accessible if you know where to look. You may want to look at a spoke style cell though, as they're shorter.
The pulling device itself is another issue, but there are many styles and I'll work out as many easy ones as I can to demonstrate. You may not want to lug a giant lever or Jack up a cliff, but this style allows you to pull ground based test pieces at least
The spoke/pancake style load cells do have a lower profile, but hooking it up into a variety of tension test systems seems like a hassle to me; which is what I'm primarily plnning to do. I already ordered a 50kN S-Style load cell for the equivalent of $330 USD, it'll fit my planned setups: One is to pull in tension different bolts and hardware (some of which I buy directly from manufacturers for better pricing), & to batch test them too. I was chatting with Bobby Hutton. He suggested using a metal stool & a bolt puller, and to also include paracord "fuses" that break around 6kN.
For break testing, my original plan was to make a 4:1 using dyneema tow rope, four snatch blocks and pull with my 2-ton 6m chain come along (lever chain hoist). But Bobby said they're more of a hassle to reset, and suggested a 2:1 with a stronger hoist. So I ordered two 12 ton snatch blocks, a 6 meter 12 ton dyneema tow rope, a 6-ton lever chain hoist (w/ 3 meters length), + a variety of metal & soft shackles. Coming directly from China, the 2:1 setup+ lever chain hoist cost me about the equivalant of $230USD. I have secluded outdoor areas I can setup as a "lab" to do break tests in real rock. Once everything arrives and I get setup, I plan to make some videos to share. There are definitely people out there interested in conducting more affordable break testing with adaquate setups.
Awesome! Yeah Bobby knows much more about this stuff than I do, but I'm glad I can help out with some inspiration about doing it cheaply! I'm working on other dirtbag rigs but what you describe with the pulleys is basically my original setup. Pulleys and dyneema, definitely a hassle. I have a 12v winch but it's a lot of gear to lug around to a cliff. If you have your car to pull, that's probably the simplest but pulling speed will vary. Keen to see how yours turns out!
@@MountainMullet I made a short video of my first break test in rock ua-cam.com/video/bXnOzaq7CHY/v-deo.html
Looks jank AF - I love it ! Have you even seen Mikls hydraulic puller - cylinder on a tripod with remote manual pump ? Not sure if he's still got it somewhere. This more for shits and gigs or actually looking to proof test some bolts in the wild ?
Cheers mate! Yeah the proper ones have the tripod and hydraulics. Cost about 2 grand. These ones in this video were just a few things I threw together to demonstrate that you can do this stuff simply and cheaply. You could totally use these on test samples though. My actual rig is pulley-based, but it's a hassle to set up. You'll see that sometime. But my main project is making a tripod-style thing without any special tools that can be used for testing or just removing old bolts. That's taking a while but hopefully soon I'll have something workable
Ah nice, presumably not too dissimilar to the screw based doodad/YABRs on a tripod with some adapter to pull hangerless carrots ?
Yeah similar idea to that, but trying to find a load cell that works without making it too huge or expensive