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|    rec.crafts.metalworking    |    Metal working and metallurgy    |    215,319 messages    |
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|    Message 214,409 of 215,319    |
|    Jim Wilkins to All    |
|    Re: 250 LbsRe: How Big Is The Disc    |
|    07 Jun 25 09:47:58    |
      From: muratlanne@gmail.com              "Bob La Londe" wrote in message news:10204dd$2jbi9$1@dont-email.me...              I use whatever is easiest for lifting. I looked everywhere for my dad's       old chain fall, and after I bought one I finally found his in one of his       old trucks. I've got multiple cable pullers, a tractor with front       implement forks, & 2 chain falls now. LOL. Pulling a burned out       compressor out of an AC condensing unit works really well with a       straight pick across the rungs of a 12 foot step ladder and a cable       puller. Whatever works. I sold an old Cummins engine a while back and       loaded it with a tiny little cable puller, a giant cheater bar, and an       old steel A-frame that barely fit around the bed of the truck. It was       all I had at that location. Whatever works.              Bob La Londe       --------------------------              I made do with "whatever works" for a long time. What I've described was       finally satisfactory at low cost. The people across the street had a tripod       of 2" pipe to pull and swap engines between old vehicles that inspired me to       design and make my own adequate hoisting equipment instead jury rigging       which sometimes broke.              I switched from cable to chain pullers mainly to gain more lifting height       under fairly low support, and liked them well enough to repurpose the cable       pullers for horizontal and angled pulls. A two ton lever chain hoist is much       easier to operate near full capacity than a similar cable puller as the reel       fills up. A chainfall is necessary when the hoist is too high to reach.              I now have 1 and 2 ton chainfalls, lever chain hoists of 1/4, 1/2, 3/4, 1       and 2 tons, and uncountable cable pullers, mostly damaged from rapid wear of       soft steel stampings. When running the sawmill most of the chain hoists are       in use for either handling logs or storing lumber.              The enabler was online column loading calculators like this that showed the       surprisingly high capacity of 2" x 8' chain link fence posts and 2" x 10'       electrical conduit as long as the loading is purely axial. The fence posts       have the 2-3/8" OD of 2" pipe, the conduit its ID.              Pipe is stronger but a 100 Lb tripod of it is difficult to set upright when       its center of gravity is above shoulder level. A 10' tripod of 2" conduit is       manageable without back strain.       https://amesweb.info/Beam/Column-Buckling-Calculator.aspx       A long thin column's load capacity depends on the metal's elastic constant       instead of its (greater) compression strength. It will bow rather than crush       like a short column.*              The only sign of hoisting overload that I've seen after heavy logging abuse       has been the top bolt holes being pulled oval. I changed from hardware store       Grade 30 to logging Grade 70 chain to upgrade the tripods for the 4500 Lb       logs. Overhead-rated chain of Grade 80 and above has shorter links that       won't accept a bolt or shackle pin to adjust length except at the ends. My       manual chainfalls don't apply the electric hoist starting shock load that       Grade 80 and above will tolerate better. It stretches when overloaded while       lower grades may be brittle.              To keep leg column loading axial I put acorn caps in sockets at the bottom       and pinned the top connection with the loading shared between both sides.       The acorn caps for 2" conduit are old cast iron ones from a fence dealer's       junk drawer turned down to press fit inside the conduit. The acorn shape       holds on a level baseplate better than ball caps. So far even the thin cast       aluminum ones on fence posts have held up unless punctured by a rock.              The sockets are holes in metal base plates, some flared like trumpet horns       with hammer and anvil. The downward flare and bent-down corners have kept       them from sliding on turf. On loose sand the plates need to be larger and       dug in at an angle. I tied the bases together on the gantry tripods. A wye       is less of a tripping nuisance than a delta, and easier to reposition.              Although I calculated the load capacity I'm not confident enough to claim a       number, or show how I joined the tops of the tripod legs. There are several       top bracket versions to copy. I haven't seen mine anywhere, which may be a       bad sign. I proof tested my work by trying to pull large stumps.       https://www.amazon.com/4400LBS-Digital-Industrial-Electronic-Han       ing/dp/B0B28FJYG9              *Surprisingly at the load where a column starts to bow its load capacity is       the same no matter how far it bends, until it fractures. I saw this lifting       a small log with shear legs of 12' 2x4s, the bent leg would remain stable       wherever I pushed it with my hand.              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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