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  1. #21
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    "I've seen a lot of guys go nuts over the concrete under a 2 post. It's kind of ridiculous. Most auto shops are lucky to have 5" and they rack vehicles constantly."

    It's one of those situations where it's easy and cheap to overkill, and there's no downside to overkilling it. Sure, lots of shops have 5" of concrete and GET BY with it. But then, lots of shops are operated by dopes and manned by dopes. And often the dope who half-assed the lift installation is not the dope who's under the vehicle. What does he care if the F-350 flattens someone? Any machinist who is used to working with steel and has watched concrete crumble apart will understand why you spend another $200 and overkill your lift installation.

  2. #22
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    I grew up in a mechanic shop (three locations as we grew) never had a hoist go over but dad insisted in yards of concrete under each hoist anchor bolts welded to the re bar. on the other hand I haven't got the fingers and toes to count the number of hoists I've either heard of or witnessed coming out of the floor. failed anchors, chunks of floor and broken head bolts (old center air / hydraulic cylinder). Shops don't leave them like that even for a few minutes if they can help it. would you take your car to a shop with a hoist tilted over?? a hoist cylinder once blew with my brothers fingers atop the trans bell housing under the pinch welds. fortunately he was installing the transmission with a transmission jack and that was what kept the vehicle from falling to the ground and killing him, but his fingers got crushed and all he could do was scream for help. fortunately I was only about fifty feet away. to my point, things go wrong with hoists, weight is never perfectly centered and often you are working alone. can you rig it to work? yes, but chances of it all going wrong at an in opportune time are very high. take your time and do the job overkill style, it's worth the time and money, and trust me a hoist saves a lot of both. all in all good tool score!

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  4. #23
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    Quote Originally Posted by hvnlymachining View Post
    I grew up in a mechanic shop (three locations as we grew) never had a hoist go over but dad insisted in yards of concrete under each hoist anchor bolts welded to the re bar. on the other hand I haven't got the fingers and toes to count the number of hoists I've either heard of or witnessed coming out of the floor. failed anchors, chunks of floor and broken head bolts (old center air / hydraulic cylinder). Shops don't leave them like that even for a few minutes if they can help it. would you take your car to a shop with a hoist tilted over?? a hoist cylinder once blew with my brothers fingers atop the trans bell housing under the pinch welds. fortunately he was installing the transmission with a transmission jack and that was what kept the vehicle from falling to the ground and killing him, but his fingers got crushed and all he could do was scream for help. fortunately I was only about fifty feet away. to my point, things go wrong with hoists, weight is never perfectly centered and often you are working alone. can you rig it to work? yes, but chances of it all going wrong at an in opportune time are very high. take your time and do the job overkill style, it's worth the time and money, and trust me a hoist saves a lot of both. all in all good tool score!
    Complete bullshit.

    Exactly how was the lift going to fall on your brother when the hydraulics failed?

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    Quote Originally Posted by Garwood View Post
    Thankfully lift installers aren't engineers!
    The lifts were designed by engineers an the anchorage requirements were designed by engineers.Departing from their recommendations frees the manufacturer from liability.

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    Quote Originally Posted by Garwood View Post
    Complete bullshit.

    Exactly how was the lift going to fall on your brother when the hydraulics failed?
    straight down, air over hydraulic single center post, antiques by today's standards they were notorious for failure but we were a young business with little money.

  7. #26
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    Quote Originally Posted by hvnlymachining View Post
    straight down, air over hydraulic single center post, antiques by today's standards they were notorious for failure but we were a young business with little money.
    Your post read like it was a 2 post. That's why I called BS. 2 post can't do that.

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    Quote Originally Posted by Illinoyance View Post
    The lifts were designed by engineers an the anchorage requirements were designed by engineers.Departing from their recommendations frees the manufacturer from liability.
    We all know exactly how that works and as Practical Machinists we do a lot of our own engineering and have to deal with other's "engineering" on a daily basis.

    I've met a lot of fucking worthless engineers who wholeheartedly believe they are god's gift to all creation because they possessed the holy ability to memorize and regurgitate shit for 4 years. It has been my experience the more fucking worthless they are as an engineer the more they spout off about the required educational certificates to do basic things. Good engineers understand that the degree they got is only as good as their ability to apply what they learned to the task at hand and furthermore, said ability can also be present in others that don't have the same piece of paper.

    You may or may not be the fucking worthless engineer type, but you should understand that formal education does not directly correlate with intelligence nor ability.



    I have been around 2 post lifts my entire life. I have installed many of them from across the entire spectrum of era and quality. The basic requirement from the OEM's is 4" of concrete. Older models will spec thicker in their installation instructions even though they are considerably heavier built with more surface area and attachment points.

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    Quote Originally Posted by Garwood View Post
    Your post read like it was a 2 post. That's why I called BS. 2 post can't do that.
    sorry about the confusion. it was an older single post like you see in classic filling station photos, they were dangerous and required manual set safeties that were sometimes in the way. The single seal holding all of the pressure was a packing with a short lifespan.

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    Your proposed solution will give your insurance agent diarrhea on the spot.

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    Quote Originally Posted by sealark37 View Post
    Your proposed solution will give your insurance agent diarrhea on the spot.
    So you're saying it's worth it...

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    Man even if it worked fuck that... what kind of hilly billy shit is that to try and actually use the hoist to do productive work. I guess I'm just really lame and boring and enjoy working in a clean, properly laid out environment. I have worked in a bunch of shops and people put hoists in stupid places all the time.

    Dumb, get some god damn concrete, you got the hoist for free.

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    A 25 x 30 foot concrete slab wouldn't cost that much and you would have a nice flat smooth area to work on.

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    Unless you have access to the steel plates way under market price you'd be better off pouring a concrete pad. My 10,000# hoist is mounted on 6" reinforced concrete so now worries there. One of the nicer things that I've bought for myself in the last 30 years. You're going to love having one handy.

  17. #34
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    Quote Originally Posted by Garwood View Post
    I've met a lot of fucking worthless engineers who wholeheartedly believe they are god's gift to all creation because they possessed the holy ability to memorize and regurgitate shit for 4 years. It has been my experience the more fucking worthless they are as an engineer the more they spout off about the required educational certificates to do basic things. Good engineers understand that the degree they got is only as good as their ability to apply what they learned to the task at hand and furthermore, said ability can also be present in others that don't have the same piece of paper.
    Well said!
    There are good ones who actually understand how things work also but do not seem to be the norm.

  18. #35
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    Look at what the forces are on the two posts: The car is between the posts. The weight supported by 3'-4' arms, This means the two posts are trying to be pushed apart at the bottom, yes, the pads touching the frame of the car would have to slip, but I've been under some very rigid lifts when the pads slipped on the frame due to slippery undercoating, or someone prying or yanking on something on the truck or car.

    I'll suggest selling the two post lift and buying a good 4 post lift, they will work fine on a firm dirt floor. They are not as nice to use as a two post. I have two 4-ost lifts, and several times when needing to do an extensive underside cleaning or sandblasting of a chassis or underside of a car, I'll put the lift on two long 2x12's or long lam-beards. Lag bolt the column pads to the wood. Drag the lift on the wood skids out into the yard and make a mess out in the yard, Then bring it back inside.

    For a 2-post lift, I'd NEVER consider anything smaller than a 12'x20' Concrete pad, rebar reinforced and at least 6" thick and at least 5-bag mix.

    I've spent way too many years of my life under a lift to even consider getting under one that is the least bit 'Mickey-Mouse'.

    DualValve

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    Many modern lifts are asymmetrical, meaning the weight is cantilevered toward the rear of the vehicle. Mine is built that way. The side load is only an issue for base plate style lifts. In a clear floor model the top bar takes the load.

    I’d never put a lift on steel plates but it would probably work. I mean they make lifts that are portable and don’t even need to be anchored to the floor.

    FWIW my dad has had a single post in ground lift in his shop my whole life. It’s always worked fine. I worked in another shop that had some 2 post in ground lifts where the two sides were connected by a rack and pinion with a shaft in a channel under the floor between the posts. Those lifts were awesome.

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  21. #37
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    Quote Originally Posted by ewlsey View Post

    I’d never put a lift on steel plates but it would probably work. I mean they make lifts that are portable and don’t even need to be anchored to the floor.
    Most concrete anchor studs are around grade 5 or so equivalency in strength. With a properly drilled and tapped hole in 1" thick A36 plate, and a cap screw of the right length to get near full thread engagement (hell, go though and into the dirt), you'll have pullout strength better than almost all concrete anchors, and no risk of the concrete being below spec strength.

    So with the right earth anchors at the ends (and maybe a few in the middle) of the 4' x 8' plate to prevent shifting or tipping, I'd have no worries about using the lift for most work. Would likely not use it to max capacity, but I have the same rule for my asymmetric lift on ~4.5" concrete here - cars only, no trucks.

    I'm a safety-first kinda guy, so if I'm OK with this, that says something. In an ideal world I'd take those plates, bed them level with a good 6"+ of 4K concrete along with a bunch of tapped holes for J bolts in the bottom for anchoring, and additional free tapped holes for pull frames to straighten chassis and other fixturing. Throw in some rebar and/or steel mesh for additional reinforcement.

    Bolt the lift in place, now you've got the best of both worlds.

  22. #38
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    Re: Single Post lifts...we took out the old single post from the shop (built in 1919) and there was a hole left in the foundation, about 12" diameter and 8 feet deep. There was a bunch of oil and water slop in it. The next morning, we could see a bunch of footprints all over the floor...a raccoon had gotten in and fallen in the hole. He somehow got out and was long gone, but the footprints bore evidence that he staggered around like a filthy drunken sailor for some time, lol.

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  24. #39
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    I’d drill a couple 12-14” holes 4-5’ deep and tube it. Burn out two 15”x15” pieces from your 1” plate, drill/weld rebar on, lay out the post mounting hole locations and drill/tap. Set the plate in the wet cement but leave the tube stubbed out 5” or so. Epoxy the future gap between the bottom steel plate and new cement.


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