Shop and Tools: Tips and Tricks

[Yotota]

That's really tiny, and not pinned into the existing slab? Seems like it would encourage the post bases to sink below the surface of the existing slab.

Absolutely. Run that by an American structural/civil engineer and I doubt anyone would stamp it. I've done enough projects with floor mounted equipment to know that this is an area outside my "good enough" zone of knowledge.

The only method I could think of is to mount the lift to some 1" thick steel plates, maybe 48x72" at a minimum, and then anchor those plates to the slab around the perimeter.

 

[665.0coupe]

Absolutely. Run that by an American structural/civil engineer and I doubt anyone would stamp it. I've done enough projects with floor mounted equipment to know that this is an area outside my "good enough" zone of knowledge.

The only method I could think of is to mount the lift to some 1" thick steel plates, maybe 48x72" at a minimum, and then anchor those plates to the slab around the perimeter.

Seriously?!? Have you ever actually seen a two post lift mounted to two 48x72" steel plates? I understand spreading the load out, but I'd say 48x72 is past the point of diminishing returns. Use the drawing posted above but pin the new concrete to the existing slab and it will be fine.

 

[arse_sidewards]

Seriously?!? Have you ever actually seen a two post lift mounted to two 48x72" steel plates? I understand spreading the load out, but I'd say 48x72 is past the point of diminishing returns. Use the drawing posted above but pin the new concrete to the existing slab and it will be fine.

This. 6ft by 4ft is just insane to the point of comedy.

You'd be money ahead (and have a way stronger result) building a square out of some sort of structural steel, bolting the lift to that and then cutting out some floor and dropping it in.

 

[Yotota]

Seriously?!? Have you ever actually seen a two post lift mounted to two 48x72" steel plates? I understand spreading the load out, but I'd say 48x72 is past the point of diminishing returns. Use the drawing posted above but pin the new concrete to the existing slab and it will be fine.

No, I haven't... But I have dealt with concrete slabs on numerous past work projects. Especially mounting industrial equipment in old facilities. And I've mounted equipment on larger plates than that.

The dead load of the lift+vehicle isn't my concern; attachment to the concrete is the issue. Old, brittle concrete can't take much upward force in an anchor before the concrete spalls. A properly balanced vehicle on a two-post lift (CG directly centered with the posts) wouldn't necessarily create any lift forces on the anchors, but any rocking would. Add in balancing error and that increases significantly.

I'm sure a legit structural/civil could spec a smaller plate to meet those requirements, especially if the slab is of known good quality. But my slightly experienced guesstimate would be a 4x6 plate for each post on old concrete.

 

[billybob_81067]

I'm sure a legit structural/civil could spec a smaller plate to meet those requirements, especially if the slab is of known good quality. But my slightly experienced guesstimate would be a 4x6 plate for each post on old concrete.

Yeah probably 4'x4' you know like how the drawing is with the concrete pad below the surface being 4'x4'. And even that is probably a retarded amount of overkill...

 

[Yotota]

Yeah probably 4'x4' you know like how the drawing is with the concrete pad below the surface being 4'x4'. And even that is probably a retarded amount of overkill...

That's still a huge "it depends" situation...

What's under the footer? What is the strength and integrity of the existing slab? Etc.

There is no way to say "do what that drawing says and you'll be good to go".

 

[bgaidan]

Absolutely. Run that by an American structural/civil engineer and I doubt anyone would stamp it. I've done enough projects with floor mounted equipment to know that this is an area outside my "good enough" zone of knowledge.

The only method I could think of is to mount the lift to some 1" thick steel plates, maybe 48x72" at a minimum, and then anchor those plates to the slab around the perimeter.

Seriously?!? Have you ever actually seen a two post lift mounted to two 48x72" steel plates? I understand spreading the load out, but I'd say 48x72 is past the point of diminishing returns. Use the drawing posted above but pin the new concrete to the existing slab and it will be fine.

My 10k lift just spec'd a piece of 2x2 1/4" angle, maybe 2' long on each base, parallels to the vehicle. That was for mounting on an existing slab. With a thickened slab for the lift, they weren't required.

 

[GLTHFJ60]

The only method I could think of is to mount the lift to some 1" thick steel plates, maybe 48x72" at a minimum, and then anchor those plates to the slab around the perimeter.

Not jumping on the hate bandwagon, this would def work, but dang that would be expensive. I bet the steel plates to do that would be 1-3x the cost of the lift itself, lol.

 

[speed bump]

Not jumping on the hate bandwagon, this would def work, but dang that would be expensive. I bet the steel plates to do that would be 1-3x the cost of the lift itself, lol.

For $2-3k I can pour a lot of new concrete. That's also a larger anchorage than the 2.5 ton 10 ft jib crane which installs on a 6" slab I was looking at uses (54" diameter base).

I am really confused how a 16 sq ft pad poured 8 inches thick with rebar under the slab on what a geotech would call settled soil is going to be inadequate for a lift that is spec'd as wedge or epoxy anchored into a 4 inch slab.

 

[GLTHFJ60]

For $2-3k I can pour a lot of new concrete. That's also a larger anchorage than the 2.5 ton 10 ft jib crane which installs on a 6" slab I was looking at uses (54" diameter base).

I am really confused how a 16 sq ft pad poured 8 inches thick with rebar under the slab on what a geotech would call settled soil is going to be inadequate for a lift that is spec'd as wedge or epoxy anchored into a 4 inch slab.

I mean I'm not a math junkie, but two 36"x36" pads does not equal 16 square feet. Remember we're talking about that maxjax spec sheet on the previous page.

Engineered drawings I've seen, albeit for larger two post lift capacities, show something like 10'x12' caisons cut in, doweled into existing, with cages, poured with 3kpsi or better mud. It's not like you put a couple of (effectively) pavers in without pins and you can safely lift a car.

I'm not a civil or structural engineer though, so idk. Just doesn't feel right.

 

[aczlan]

I mean I'm not a math junkie, but two 36"x36" pads does not equal 16 square feet. Remember we're talking about that maxjax spec sheet on the previous page.

Engineered drawings I've seen, albeit for larger two post lift capacities, show something like 10'x12' caisons cut in, doweled into existing, with cages, poured with 3kpsi or better mud. It's not like you put a couple of (effectively) pavers in without pins and you can safely lift a car.

I'm not a civil or structural engineer though, so idk. Just doesn't feel right.

But a 48"x48" pad does and that is what is called for, look at the drawing again, specifically the side view.
It is drawn as 12" thick, the top 4" (where it goes through the existing slab) is 36"x36" the rest (under the existing slab) is 48"x48":

Found this online.

It's an often asked question--how to install 2 post lift on old/unsuitable/unknown concrete. I'll be doing this someday, so saving it here:

Aaron Z

 

[GLTHFJ60]

But a 48"x48" pad does and that is what is called for, look at the drawing again, specifically the side view.
It is drawn as 12" thick, the top 4" (where it goes through the existing slab) is 36"x36" the rest (under the existing slab) is 48"x48":


Aaron Z

Good call out, but still, seems insufficient. Maybe kosher for a 5k maxjax. 48" sub-existing BTW, not at the surface.

This is the folly of people like me though. I don't have the structural engineering background to know what's sufficient, so in my mind I want it to be built like a brick shithouse.

 

[aczlan]

Good call out, but still, seems insufficient. Maybe kosher for a 5k maxjax.

This is the folly of people like me though. I don't have the structural engineering background to know what's sufficient, so in my mind I want it to be built like a brick shithouse.

That's also what Rotary calls for on their 7-10k non-siesmic lifts (4'x4' at least 6' thick for each side):

And here is what Bendpak wants for their similar size lifts for a retrofit slab (4' long by the width of the posts plus 1' by 12" thick up to 10k, 6' long for 12k and over) :

Aaron Z

 

[OX1]

That's still a huge "it depends" situation...

What's under the footer? What is the strength and integrity of the existing slab? Etc.

There is no way to say "do what that drawing says and you'll be good to go".

Agree on that. I'd be doing an entire new slab, over the entire work/mount area under the lift.

 

[OX1]

SINGLE Accessary serp "noise" finder....................

 

[GLTHFJ60]

That's also what Rotary calls for on their 7-10k non-siesmic lifts (4'x4' at least 6' thick for each side):

And here is what Bendpak wants for their similar size lifts for a retrofit slab (4' long by the width of the posts plus 1' by 12" thick up to 10k, 6' long for 12k and over) :

Aaron Z

Nah dude you're wrong there. For their smaller lifts they say 48" width min, with min 6" keyed under existing (and doweled) but the length is 12" min wider than the lift base. That's not two small ass pads, that's a caison thats the whole lift width. Completely different.

 

[aczlan]

Nah dude you're wrong there. For their smaller lifts they say 48" width min, with min 6" keyed under existing (and doweled) but the length is 12" min wider than the lift base. That's not two small ass pads, that's a caison thats the whole lift width. Completely different.

And I said what they wanted:

They also say that a 6" key is a suitable alternative to doweling:

Aaron Z

 

[arse_sidewards]

SINGLE Accessary serp "noise" finder....................

Mechanic's stethoscopes is $5-8 and does the job real good.

But a mechanic's stethescope can't be re-purposed to bench test shit so win for that.

 

[GLTHFJ60]

And I said what they wanted:


They also say that a 6" key is a suitable alternative to doweling:



Aaron Z

Ah. Frankly I only glanced at it because I thought you were arguing that the maxjax spec was similar on larger lifts, which I guess we both know is not.

 

[speed bump]

I mean I'm not a math junkie, but two 36"x36" pads does not equal 16 square feet. Remember we're talking about that maxjax spec sheet on the previous page.

Engineered drawings I've seen, albeit for larger two post lift capacities, show something like 10'x12' caisons cut in, doweled into existing, with cages, poured with 3kpsi or better mud. It's not like you put a couple of (effectively) pavers in without pins and you can safely lift a car.

I'm not a civil or structural engineer though, so idk. Just doesn't feel right.

I'm not sure I've seen that much concrete for the average surface mount jib crane much less a two post lift.

You have to figure on the lift side they figured out what the bearing surface they needed on the concrete for the load not to destroy the concrete. They figured out the fastener sizing that you shouldn't ever load a single fastener to failure with the given fasteners they recommend. Assuming proper installation into the concrete you shouldn't rip it out of the concrete. That 4x4 pad with rebar is setup with the assumption that you didn't pour on complete shit you can't overload the soil. With the pour design you get a bunch of extra uplift protection from the existing slab.

I'm not a structural engineer but for shit that doesn't vibrate (exception being tanks) that much concrete is generally inline with what I see for the load a lift will see.

 

[pennsylvaniaboy]

I know this isnt a tip or trick compared to some, and i believe it was actually listed earlier in this thread. With the recent fab work I have been doing, I have been opening up holes in brackets, and tabs. Adding weld washers, etc. I used to use drill bits for this but someone had recommended reamers......What an improvement. Im not even using anything fancy, just amazon specials

https://www.amazon.com/gp/product/B00FXJGSLI/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&th=1

 

[Yotota]

I know this isnt a tip or trick compared to some, and i believe it was actually listed earlier in this thread. With the recent fab work I have been doing, I have been opening up holes in brackets, and tabs. Adding weld washers, etc. I used to use drill bits for this but someone had recommended reamers......What an improvement. Im not even using anything fancy, just amazon specials

Amazon.com

Hell yeah, I need to order a couple of those. I rely too much on step bits for reaming.

How much taper do they have? The pics look like the tip is maybe 50% of the max diameter... is that right?

 

[Muckin_Slusher]

Hell yeah, I need to order a couple of those. I rely too much on step bits for reaming.

How much taper do they have? The pics look like the tip is maybe 50% of the max diameter... is that right?

i think my 5/8 bridge reamers will start out on a 1/4 or 5/16 hole, so yeah, abut half.

 

[Wisconsinite]

Working on some ways to make tubing measurments easier. This one is for 1.75" tube, and the top "block" is 1.75", should make it easy to get inside/outside dims. The boss on the top is 1.00"OD. Clips on pretty tight, get it level, and then check your dimensions.

 

[Sluggy]

Glue a fridge magnet to make it stick better

 

[Wisconsinite]

Glue a fridge magnet to make it stick better

It doesn't need it. I have designed/tested/revamped it to require a decent amount of pressure to clip on the tube. It isn't going anywhere.

We did think about embedding magnets, though.

 

[Sluggy]

So the real questing now...how much for one to my door? 1.5/1.75

 

[Wisconsinite]

So the real questing now...how much for one to my door? 1.5/1.75

Do you think one would be that useful? I am printing a bunch, and we are going to put em to the test this weekend. I am thinkning a person would want 2 per size, minimum.

Ran out of black filament, now we are onto bright orange.

 

[YJBrian]

Working on some ways to make tubing measurments easier. This one is for 1.75" tube, and the top "block" is 1.75", should make it easy to get inside/outside dims. The boss on the top is 1.00"OD. Clips on pretty tight, get it level, and then check your dimensions.

Very nice - 3D printers are great aren't they?

 

[SMI17]

Do you think one would be that useful? I am printing a bunch, and we are going to put em to the test this weekend. I am thinkning a person would want 2 per size, minimum.

Ran out of black filament, now we are onto bright orange.

Price shipped to 50265?