# Shop press build



## ShawnR (Nov 3, 2021)

I decided to finally build a shop press. Working on a meat slicer now and I need to remove a pressed bearing. Although I could go somewhere (a puller does not seem to even scare it), I am going to use up some material in the shop and make it into something useful other than a tripping hazard or fall threat! I have often wanted one but would not stop that project to build one. I am hoping to be able to do some press breaking with it too.

The posts and top are 2 x 3 x .250" tubing. The jack will be a 6 ton for now because I have one to prototype with but hoping (considering based on input here) to move to a pneumatic/hydraulic jack if all goes well when the press is done. Like this one but the 12 ton version (that page is not loading for me ) Is the pneumatic version good for this application or would the lack of "feel" or speed a bad thing for this application?



			https://www.canadiantire.ca/en/pdp/motomaster-20-ton-pneumatic-hydraulic-bottle-jack-0091012p.html
		


The holes are 9/16" right now. Question...how do I know or find the shear strength of a bolt/rod? For this application, I am thinking that 9/16" is lots. I was going to go 1" when I started planning but considering the tube is only 2" wide, that would not leave a lot of meat beside the hole.

The holes are 12" apart since the jacks have about 10" of travel, I figured this would be ok.

Input is good. I have not used presses very much.

Thanks
Shawn


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## Chicken lights (Nov 3, 2021)

With a pneumatic jack, you build air pressure to move the ram, so if it’s stuck and you keep feeding it air, once it loosens the air pressure should drop. If that makes sense.


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## RobinHood (Nov 3, 2021)

ShawnR said:


> Question...how do I know or find the shear strength of a bolt/rod?



I use an app called iEngineer. Here is the result (yellow arrows - shear strength depends on how the bolt shoulder / thread is loaded) for a 5/16-12, gr8 bolt.


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## ShawnR (Nov 3, 2021)

Chicken lights said:


> With a pneumatic jack, you build air pressure to move the ram, so if it’s stuck and you keep feeding it air, once it loosens the air pressure should drop. If that makes sense.



Are you talking about an air cylinder? I think the jack I was referring to just uses an air actuator to move the hydraulic pump.

@RobinHood Thanks. That is the number I was looking for. Even higher than I expected so considering there will be 4 contact points, a Grade 8 9/16 bolt will have much more shear resistance than a little bottle jack will deliver. I will check out more engineering sites. I googled the other day but the first few hits did not yield what I was looking for. Figured someone here could give me quick direction. Thanks!


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## Tom Kitta (Nov 3, 2021)

I made my own shop press and then realized that farmers are selling shop presses 10x as strong for 5x less then the price of steel used in them. 

Whatever you do do NOT base your design on stuff in Princess Auto /  Busy Bee / KMS / Canadian Tire etc. Their designs are marginal even when you increase them by a factor of 1.5. If you are going to copy the design make sure you more then double the strength of everything they have - preferably triple it. 

I went with 1.5 and I am not too happy. It is true that the presses they sell deform under load - when you do actual calculations with mild steel you see at full load PA press when positioned perfectly will be at 90% or so of its plastic deformation limit.


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## Mcgyver (Nov 3, 2021)

I've not used one those pneumatic/hydraulic jacks so I guess I could be missing something, but I think a pneumatic press seems like a bad idea.  The reason is, what being pressed (out) can or will sudden present about no resistance.  Nothing violent happens at that point with a hydraulic press as liquids more or less don't get compressed where a gas does and will want to keep things moving at a high rate of speed once resistance drops/disappears.  Good news is it might do double duty as a hammer 

If I've miss something with how they work, apologies and i look forward to my education


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## Tom Kitta (Nov 3, 2021)

air over hydraulic is just your hydraulic jack that in addition to a small emergency hand pump (usually supplied) has a small air powered motor that does all the hydraulic work. Instead of you doing all the work the air does it in not too efficient manner. But it is small. 

You can have electric hydraulic jack where electric motor does the same thing - electric hydraulic pump systems are common. 

If you can get air over hydraulic - do it - it makes working the press much easier. Heck, next step is electric hydraulic - used in bigger presses a lot.


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## ShawnR (Nov 3, 2021)

@Mcgyver ...what @Tom Kitta says. The air system just does the pumping for you. It is still a hydraulic bottle jack.  I figure if the air was controlled by a foot valve, then it frees up the hands to hold or position the work. I thought safer and more convenient. Yes Tom, mildly considering a full electric version.....That would be Gucci!!    I have not looked for components yet. I will do some research tonight


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## ShawnR (Nov 3, 2021)

Tom Kitta said:


> I made my own shop press and then realized that farmers are selling shop presses 10x as strong for 5x less then the price of steel used in them.
> 
> Whatever you do do NOT base your design on stuff in Princess Auto /  Busy Bee / KMS / Canadian Tire etc. Their designs are marginal even when you increase them by a factor of 1.5. If you are going to copy the design make sure you more then double the strength of everything they have - preferably triple it.
> 
> I went with 1.5 and I am not too happy. It is true that the presses they sell deform under load - when you do actual calculations with mild steel you see at full load PA press when positioned perfectly will be at 90% or so of its plastic deformation limit.


I have looked at some presses for design ideas but there are not many options for a simple press. I am just using what I have and figure the rectangle tube at wall thickness of 0.250" will be strong enough for my work. I know a lot of them use channel but this is another of my projects to get something out of stock in the shop. It seems tall but probably by the time I mount the jack, it might not be too bad. Having the room below it might be handy sometimes. I did not want a bench press.


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## ShawnR (Nov 3, 2021)

This looks interesting. Might be nicer than a bottle jack. Anyone familiar with it?



			https://www.princessauto.com/en/product/PA0001270248


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## Susquatch (Nov 3, 2021)

ShawnR said:


> Like this one but the 12 ton version (that page is not loading for me ) Is the pneumatic version good for this application or would the lack of "feel" or speed a bad thing for this application?



I have a 12 ton that I use for changing tires on my big row crop tractor. You are correct about how it works. The air just moves the pump Lever so you don't have to manually pump it. The thing only requires 20psi or so to work, but it needs huge airflow and it really really really slows down (even at 100psi) when the Hydraulic pressure gets high. Frankly, I have never been thrilled with the way it works but it does beat hand pumping. 

It has zero feel to it. That's bad when you are working close to the edge. At those capacities, there isn't much feel to begin with. 

I put mine in my 20 ton press once when the original jack started leaking, but replaced it with another standard jack not long afterward because I crushed too many parts with it.


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## whydontu (Nov 3, 2021)

ShawnR said:


> This looks interesting. Might be nicer than a bottle jack. Anyone familiar with it?
> 
> 
> 
> https://www.princessauto.com/en/product/PA0001270248


I haven’t used the PA version, but we use the real one all the time. The ability to change cylinder dimensions, and remote-mount the pump makes for much easier implementation on our  test stands (we do pressure testing of industrial valves, and holding the test heads with a frame and hydraulic jacks is 100x faster than bolting up pipe  flanges)



			https://www.enerpac.com/en-us/tool-sets/USCylinderandPumpSets


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## Susquatch (Nov 3, 2021)

ShawnR said:


> This looks interesting. Might be nicer than a bottle jack. Anyone familiar with it?
> 
> 
> 
> https://www.princessauto.com/en/product/PA0001270248



I have the 10 ton version and my neighbour has the 4 ton version. They work great for the things they were designed to do but prolly would not work well in a hydraulic press. 

Around the farm, they are almost indispensable. If mine broke, I'd go get another one the day before. The separate pull cylinder is also quite useful.


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## ShawnR (Nov 9, 2021)

Pretty much finished I think. I made the shelf out of 1 x 2 x 0.125 tubing. I will see if it stands up without bending. The post has a 0.250 hole in it to act as a pilot hole so I can make different anvils for it (terminology?) The one in there is just a 1/2" piece of dowel with the pilot stub turned on it. I tried to make the press versatile as I have no particular intention for it other than just to have a shop press. I suppose the job at hand will dictate any future additions. Paint is next....  

Having said that, I tried pressing a bearing off the Hobart motor shaft and it did not seem to move. I am reluctant to just go hard as I am not sure if it just presses on but that is a point for the hobart thread. 

Thanks for the input everyone.


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## Susquatch (Nov 9, 2021)

Boy, she is beautiful!

At a safety factor of 1.0 (reasonable for something like that in a shop environment where bending out of shape in not a big issue), a 36" span, and plain steel tubing, your tubing will take about 1250 pounds each or 2500 pounds total (evenly distributed) before permanently deforming. That looks like a 6 ton cylinder so best to be very careful. Your top section looks MUCH stronger than the business end. The column load on the posts is mostly tensile so they should be fine. Prolly MUCH stronger than the top or bottom section.

That jumps to 8000 pounds total if you weld another 1x2 above or below (not beside) the existing ones.


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## ShawnR (Nov 9, 2021)

Susquatch said:


> Boy, she is beautiful!
> 
> At a safety factor of 1.0 (reasonable for something like that in a shop environment where bending out of shape in not a big issue), a 36" span, and plain steel tubing, your tubing will take about 1250 pounds each or 2500 pounds total (evenly distributed) before permanently deforming. That looks like a 6 ton cylinder so best to be very careful. Your top section looks MUCH stronger than the business end. The column load on the posts is mostly tensile so they should be fine. Prolly MUCH stronger than the top or bottom section.
> 
> That jumps to 8000 pounds total if you weld another 1x2 above or below (not beside) the existing ones.



@Susquatch Thanks! Not many of my projects receive that kind of comment! 

Where do you get the information? As mentioned earlier with regards to the shear strength, I am not sure what to even search for when looking for bending data and when I have tried, I probably get confused by what I find. I did intentionally build the top solid. ie paid more attention to my welding... as I figure this needed it. The shelf is easily replaceable if I find I am bending it. I might just do what you suggest, scab another piece below the mains to give me 4 inches of material. I also have an I beam that I could use.

Fun project.

Thanks


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## ShawnR (Nov 9, 2021)

I suppose this site might have what I want ...? I will need to spend some time on it . 






						Beam Stress & Deflection | MechaniCalc
					

This page discusses the calculation of stresses and deflections in beams.




					mechanicalc.com


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## Susquatch (Nov 9, 2021)

ShawnR said:


> @Susquatch Thanks! Not many of my projects receive that kind of comment!
> 
> Where do you get the information? As mentioned earlier with regards to the shear strength, I am not sure what to even search for when looking for bending data and when I have tried, I probably get confused by what I find. I did intentionally build the top solid. ie paid more attention to my welding... as I figure this needed it. The shelf is easily replaceable if I find I am bending it. I might just do what you suggest, scab another piece below the mains to give me 4 inches of material. I also have an I beam that I could use.
> 
> ...



It's pretty basic stress analysis based on material properties and geometry. I don't trust online calculators or apps. They might work well for the simple case they illustrate but it's waaaayyyy too easy to add one tiny little insignificant detail that most people would not even think about or even know about and it can change everything.

If you feed me dimensions and or a simple drawing, I can do the math for you and also tell you what to look out for. A press like that is just about as simple as it gets though. All my calcs will be worst case - as they should be.

But I'm not getting paid for it (and would not accept payment anyway) so it's just information not professional advice. That said, I won't help you with an overhead crane unless it's just small talk over a beer. WAY too much liability for my taste.


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## ShawnR (Nov 9, 2021)

Thanks again @Susquatch

Several times, I wondered what an appropriately sized material would do for the project at hand so being able to use  some form of calculator would be nice,...along with a better understanding of stress analysis. ....but probably just another rabbit hole. Example, I built a trailer for a skid steer years ago and wondered what material I should use. At times like that, I go see what commercial trailers are made like, and then scale up or down as I feel is appropriate. 

I am most likely like most home hobbyists, guess and then use much more than needed. In the case of this press, adding another 1x2 should suffice for my shop practices. 

But discussing things over a beer is always a good thing to do...

Thanks

Cheers,


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## whydontu (Nov 9, 2021)

Engineering Power Tools isn’t bad


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## Dabbler (Nov 9, 2021)

@ShawnR I designed a hydraulic press for a friend in the early 80s, and yield strength is a small part of the design process.  Predictable deformation at the maximum load is also a factor. 

For a 10 ton 36" span Hydraulic press I specified a table beam made out of 2 pcs of 6" X 1/2" solid bar, with spacers welded to prevent local deformation under load.  This was the lightest that would work, and it still will deform more than he specified under 10 ton load.  My vague recollection was that at 10 tons with 36" pin spacing, it would deform about ,060 under 10 tons.  to get to his .030 desired deflection, we would have needed a 9" depth and more webs welded in place.

thr problem with deflection is that 'bumping' you hear when the object suddenly moves, and that movement reduces the pressure as the table is acting like a big flat spring.

So over-design the table by several times the material and double the depth if you want a press that is both easy to use and works well.  This is why industrial presses have a hand winch to raisle and lower the table...


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## Tom Kitta (Nov 9, 2021)

I have twin 5" C that is about 3/8 with the middle of C reinforced with some scrap square segments of 1/8 wall tubing throughout its length. Span is 36" and both Cs are held in the middle with some 1/2" cut C sections (6 spacers in 3 pairs). At 10t load it flexes.


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## Susquatch (Nov 9, 2021)

Tom Kitta said:


> I have twin 5" C that is about 3/8 with the middle of C reinforced with some scrap square segments of 1/8 wall tubing throughout its length. Span is 36" and both Cs are held in the middle with some 1/2" cut C sections (6 spacers in 3 pairs). At 10t load it flexes.



It doesn't matter how strong you make it, it will always flex. It's just a matter of how much. 

So it's good to have an idea of just how much is too much. That's why I liked @Dabbler 's approach with max deflection specified. 

Anyone who doesn't believe that should mount an indicator on some heavy steel bar or plate or tube and then put a small load on it.


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## ShawnR (Nov 9, 2021)

I like where this thread. is going...... I just posted a shop project but it is becoming a good learning thread!  But leading to many more questions.....

@Tom Kitta would you post a photo of your table? 

@Dabbler Thanks! Good point. I think with my table (embarrassingly inadequate I think...), it would not take much load till I could detect deflection. I might try that tomorrow using a dial indicator. Unfortunately, no way to measure the force. I am sure there is but not in my shop.

The press width has been mentioned several times, and, of course, is a huge factor in strength. My table is 23" inside so about 25" pin to pin. 

It would be really interesting to be able to monitor the press pressure. I might watch for a deal on components to make it into a system whereby I can install a pressure gauge. My neighbour offered me an automotive frame straightening system similar to the ones posted earlier but it is only 2 ton. At the time, I had a 12 ton jack planned as my pressure source. But now considering all of the numbers kicking around, I may have to rethink that. Very unlikely I will ever need a 12 ton press but you never know what project will appear. I just grabbed 12 tons out of the air when thinking I would build a press.    

Today, when I first started pressing the hobart bearing off, I was using some small angle 1.5 x  1.5 x < 0.125 as the bearing support  (probably old bed frame...lol) . I felt like I had barely moved the jack handle and the angles were bending already. I just wanted to see how snug the bearing was. So next time I put .375" material as the bearing backers. I did not look for but neither noted any deflection when the bearing actually started moving. I guess my point is that unfortunately, with the bottle jacks, you really don't know how much force you are putting on the components. Probably the first flawed step towards an accident....

Thanks all. 
Cheers,


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## ShawnR (Nov 9, 2021)

whydontu said:


> Engineering Power Tools isn’t bad


Thanks! I will go check it out.


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## YYCHM (Nov 9, 2021)

Instrument it with strain gauges, that will keep you busy all winter


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## ShawnR (Nov 9, 2021)

Susquatch said:


> Boy, she is beautiful!
> 
> At a safety factor of 1.0 (reasonable for something like that in a shop environment where bending out of shape in not a big issue), a 36" span, and plain steel tubing, your tubing will take about 1250 pounds each or 2500 pounds total (evenly distributed) before permanently deforming. That looks like a 6 ton cylinder so best to be very careful. Your top section looks MUCH stronger than the business end. The column load on the posts is mostly tensile so they should be fine. Prolly MUCH stronger than the top or bottom section.
> 
> That jumps to 8000 pounds total if you weld another 1x2 above or below (not beside) the existing ones.


Going back to this post...but given the posts made since this one. 

My table is about 25" between pins. What does the do to the numbers versus your quote based on 36" span? Welding on another 1x2 will be what I do tomorrow. So with a narrower table and the extra material, will the table meet a 12 thousand spec? and then...what is permanently deforming? Is say 0.001 considered a permanent deformity with regards  to this discussion or is there a factor somewhere ie 1 % of the vertical (so in this case at 2" height, a 1 % deformity would be 0.020" ... am I on the right track? 

As to "evenly distributed", since the load is supported equidistant either side of centre, is this classed as evenly distributed? So if I was to move the object supports further out towards the pins, then the better for the table, although now I have longer supports....

Yea, whole bunch more questions coming....


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## ShawnR (Nov 9, 2021)

YYCHM said:


> Instrument it with strain gauges, that will keep you busy all winter



I have actually been toying with this....sounds like a good little Arduino project! I will go look for transducers. 

Thanks! Well, maybe not....


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## Dabbler (Nov 9, 2021)

Here's a more practical and simple approach.  Use one of these, but put a pressure gauge in the line.  It will need to read around 5000 or 7000 lbs or so.  The ram pressure is simple math from there.



			https://www.princessauto.com/en/10-ton-hydraulic-pump-and-ram-porta-power-kit/product/PA0001270248


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## Susquatch (Nov 9, 2021)

Some short answers for you @ShawnR .

No, pinned at both ends and loaded in the center is not a distributed load. It is more like a point load, but not quite. It depends mostly on how the load is spread out under the part you are loading in the press. The pins at the ends do simplify the math a bit but not a lot. This is one of the reasons that I am not fond of those internet sites that simplify all this stuff excessively. 

At 25 inches, your press is quite a bit stronger than at 36.  It can handle "roughly" 4000 pounds before it will start to deform permanently. With two additional 1x2 tubes, that increases to roughly 13000 pounds. Roughly is the operative word here. Small defects, Welding, material variations, corrosion, exact dimensions, thickness variations, material composition etc etc etc can all affect the numbers. I've just made a crap load of assumptions to get you close. Measuring before and after will tell you how close I got! I would not be surprised to be out 30% or more. That's what a safety factor is all about. The higher the safety factor, the less chance there is of permanent deformation and buckling. Safety factors of 2 or higher are common for things like your press. 

An Arduino is not necessary for this job but might be fun anyway.


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## Susquatch (Nov 9, 2021)

I don't know a good way to measure Hydraulic pressure in a jack. But @Dabbler has a great idea that can be used effectively with a regular cylinder. If you know the area of the cylinder bore, you can get force very easily by multiplying the oil pressure in psi by the area in square inches. It will be plenty close enough for your needs. 

Also remember that you are after one of two possible numbers. The force it takes to reach a given deflection or the force it takes to deform the press permanently. Everything else is just a bunch of numbers. Everything bends under a force. It's not if it will bend, it's how much will it bend.


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## Susquatch (Nov 9, 2021)

Here is a very short analogy to help you understand steel.

Imagine a rubber ball. If you stick your finger into it, it will deform. The harder you press, the more it will deform. When you remove your finger it will return to its previous shape. But if you press hard enough, the ball will get deformed permanently and will not return to its original shape. Steel is like extremely strong rubber. The stronger the force, the more it bends or dents. But you can only go so far before it will not return to its original shape.

This is a gross simplification just to help visualize what happens. Rubber and steel are different in many other ways. But hopefully the visual helps.


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## Brent H (Nov 9, 2021)

Ah!  @Susquatch doth tell the tale of Young's modulus !


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## Susquatch (Nov 9, 2021)

Scratch that rubber example. Here is a WAY better one. We are all used to small coil springs - like say the ones in a ball point pen. They are made of steel. You can compress them or stretch them. The harder you push or pull the more they deform. But you can only go so far before they stretch permanently. A spring is just a long steel bar. Usually a special steel, but still steel.


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## YYCHM (Nov 9, 2021)




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## Susquatch (Nov 9, 2021)

Brent H said:


> Ah!  @Susquatch doth tell the tale of Young's modulus !



Yup. His  brother was a strain on his temper though...... Groan.......


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## Brent H (Nov 9, 2021)

@Susquatch - I didn't mean to cause you any undo stress.  I realize though,  that your elastic personality would allow you to bounce back without any undo - elongation - I mean you are tall enough and would not want to yield to being stretched to the breaking point.


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## Susquatch (Nov 9, 2021)

Brent H said:


> @Susquatch - I didn't mean to cause you any undo stress.  I realize though,  that your elastic personality would allow you to bounce back without any undo - elongation - I mean you are tall enough and would not want to yield to being stretched to the breaking point.



Very well done my friend! Very well done indeed!


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## YYCHM (Nov 9, 2021)

The fact that @ShawnR knows what a strain gauge is, would indicate he knows all this stuff already


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## Susquatch (Nov 9, 2021)

YYCHM said:


> The fact that @ShawnR knows what a strain gauge is, would indicate he knows all this stuff already



It's funny what we know and don't know sometimes. I sometimes find the forum a bit awkward. Nobody wants to offend anyone else, but none of us knows what we don't know. Heck, sometimes we don't know what we do know! 

I try hard to figure out what our knowledge overlaps are so we can communicate more easily and completely, but I fail more often than I succeed.

In the end, it feels good to help and be helped even if the edges are all a bit ragged.


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## YotaBota (Nov 9, 2021)

ShawnR - are you still looking to upgrade your hydraulics? For a few bucks more than PA this would give you all the hardware for mounting the ram, a gauge and other stuff.


			https://www.canadiantire.ca/en/pdp/maximum-10-ton-shop-press-0090221p.html?_br_psugg_q=shop+press
		

And it's on sale!


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## whydontu (Nov 9, 2021)

Ancient GM show demo: 6ft length of 6”x6” steel I-beam, flat side up, supported at each end on a knife edge coming up from a concrete floor. Tenths Starrett dial gauge placed on a separate stand, at the middle of the beam, zeroed to the top face of the beam. 

Six year old pushes down on the beam, the gauge dial moves about 30*. Six year old is amazed.

Everything moves or flexes under load.


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## Dabbler (Nov 9, 2021)

Deflection in a beam is order w squared, where w is the width of the span for a given load...

I'm currently doing the sums on a shop crane with a 4X4 H beam, 15 feet long for 200 kg loads.....


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## ShawnR (Nov 10, 2021)

YYCHM said:


> The fact that @ShawnR knows what a strain gauge is, would indicate he knows all this stuff already


All this stuff?   lol....no but I get the concepts. Putting real numbers on things is the hard part and it becomes a question of am I learning fast enough to maintain my interest and justify my time or will I decide that the theory is not necessary to get the project done? The bearing came off yesterday but I don't know at what hydraulic pressure or if deflection occurred in my table. I would like to know but no other reason than putting numbers on something. And then, a whole multitude of thoughts to keep me awake.... If one press deflected the table say 0.010" at peak pressure, would a 1x2x0.125 tubing recover to zero or maintain a very slight curve? If 10 bearings required the exact same force, would the table then maintain a percentage of total deflection? and on .....as mentioned, another rabbit hole for me to trip into. 

I do enjoy these threads with many members chiming in (and a few leading the learning) . There is a vast amount of knowledge in the members here.

Thanks all!


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## ShawnR (Nov 10, 2021)

YotaBota said:


> ShawnR - are you still looking to upgrade your hydraulics? For a few bucks more than PA this would give you all the hardware for mounting the ram, a gauge and other stuff.
> 
> 
> https://www.canadiantire.ca/en/pdp/maximum-10-ton-shop-press-0090221p.html?_br_psugg_q=shop+press
> ...



Thanks @YotaBota I did see that before I built my press. I suppose I could take everything off of it and transfer it but now that I am this far, if I fall into a great deal on components, I will switch to a Ram system but for now, just going to beef it up a bit and hope something comes along that needs pressing..


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## ShawnR (Nov 10, 2021)

I found a couple of Ram sets in Winnipeg on Kijiji. I would jump on one but being 8 hours away, not going to happen. I would just order from PA. 

But if anyone following this thread wants to go down this rabbit hole with me, .....


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## ShawnR (Nov 10, 2021)

A load cell makes a Ram set look real cheap! 





__





						060-0240-02 Honeywell Sensing and Productivity Solutions T&M | Sensors, Transducers | DigiKey
					

Order Honeywell Sensing and Productivity Solutions T&M 060-0240-02 (480-6073-ND) at DigiKey.  Check stock and pricing, view product specifications, and order online.




					www.digikey.ca


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## Susquatch (Nov 10, 2021)

ShawnR said:


> All this stuff?   lol....no but I get the concepts. Putting real numbers on things is the hard part and it becomes a question of am I learning fast enough to maintain my interest and justify my time or will I decide that the theory is not necessary to get the project done? The bearing came off yesterday but I don't know at what hydraulic pressure or if deflection occurred in my table. I would like to know but no other reason than putting numbers on something. And then, a whole multitude of thoughts to keep me awake.... If one press deflected the table say 0.010" at peak pressure, would a 1x2x0.125 tubing recover to zero or maintain a very slight curve? If 10 bearings required the exact same force, would the table then maintain a percentage of total deflection? and on .....as mentioned, another rabbit hole for me to trip into.
> 
> I do enjoy these threads with many members chiming in (and a few leading the learning) . There is a vast amount of knowledge in the members here.
> 
> Thanks all!



I love the members here. I particularly love their collective experience, wisdom, and witt.

Yes, putting real numbers on this stuff is the hard part. Even when you know the theory inside out, putting real numbers on it is still the hard part. That's why safety factors are used and that's why I could be out by so much on the numbers I gave you, and that's why @Dabbler was out on his. Too many variables. Too many unknowns. The best we can hope for is to be in the ballpark and apply a safety factor to keep us out of trouble.

Does it really matter? Probably not. A basic understanding of the curve that @YYCHM provided and some thinking around how that affects a part that is being subjected to loads is enough for most of us. I really only crunched the numbers because it was apparent to me (on the basis of the experience we all get) that your design might be marginal. Adding two more cross beams above or below the others is easy and doubles the cross-section which MORE than doubles the stiffness and strength.

I think a cruise through an introductory text book on "Strength of Materials" would be useful to you and perhaps others here too. I often read text books and manuals when I go to bed. It's a great way to learn new things and it's a sure fire way to put me to sleep too!

Based on your questions, it might help to add a few thoughts:

Deflection is not a bad thing. In fact, as @whydontu & @YYCHM & @Dabbler & I have all illustrated, it is unavoidable. Any force that is applied to any beam - no matter how big - will bend it. It's not if, it's just how much! That beam is basicly a big leaf spring. The key is usually to design and build the system such that it will not permanently deform. Bigger and stronger never hurts. Too small a beam (too weak) or too big a cylinder (too much force) and it deforms and buckles when overloaded. A little spring like deflection is harmless and unavoidable. A permanently bent beam is usually not.



ShawnR said:


> If one press deflected the table say 0.010" at peak pressure, would a 1x2x0.125 tubing recover to zero or maintain a very slight curve?



10 thou over 22" is absolutely nothing. It will recover back to zero. But you should measure it! In fact, put another reference beam across the frame (a simple plate held on with Clamps will do) and then mount an indicator on it and play with it. Have some fun! I'll resist the temptation to spoil the surprise!



ShawnR said:


> If 10 bearings required the exact same force, would the table then maintain a percentage of total deflection?



Nope, the force is additive. The beam sees the sum of the forces and deflects "roughly" 10 times as much. Look at the curve that @YYCHM provided. The left half of the curve is linear.  But interestingly, if you stack these identical bearings of yours, the force will stay constant. Each bearing will simply pass its force to the next. But the stroke required to compress all of them will be 10x greater!


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## Susquatch (Nov 10, 2021)

Just thinking, a plate across the frame probably won't work all that well because the frame  flexes too. You will have to mount the plate to both ends of the beam so you can measure the curve as it changes. Even figuring out how to do that without measuring a lot of other things unintentionally will be a great learning exercise!


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## ShawnR (Nov 10, 2021)

I would probably just sit it on a stool or something under the table, independent of the press stucture.


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## Susquatch (Nov 10, 2021)

ShawnR said:


> I would probably just sit it on a stool or something under the table, independent of the press stucture.



I hope you are joking. If so, I am having a good laugh with you. But if not, I am just enjoying the moment knowing that you are going to have a lot of fun and you will learn a lot real fast! Go for it! And please keep us in the loop!


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## Dabbler (Nov 10, 2021)

For an engineering_* rule of thumb *_it is common to accept 1/600 of the width of the supports as acceptable deflection *IF *the member is an I beam, and the load is a simple one. (this comes from some basic crane design stuff I took in school)

Because you are using a welded together set of tubes you should be looking for less deflection

If you were to find a 30" I beam for your table, and your supports were 25" apart, your acceptable deflection under load would be 25/600 or 42 thou

The things is, very heavy loads over very short intervals doesn't scale very well.  The 'farmers rule of thumb' may very well work out for you. 

Frankly if you are in a big city, look up 'metal fabricators' and ask if they have a short I beam they can sell you out of their boneyard. You will also need an equally strong beam at the top of your press, so double the length you need...

I have a PA 20 ton press I picked up on sale more than 25 years ago.  It lives outside, as My shop is too small.  It is very similar to this:



			https://www.princessauto.com/en/20-ton-shop-press-with-bottle-jack/product/PA0008922585
		


from experience, we regularly get around 50 thou deflection under use, but it springs back, as I have a double U table with an additional stiffener to prevent local deflection.  You have to use these offshore presses very carefully (including the CanTire one)  The bottle jack can easily permanently deform the table they provide.  My personal rule is that if you can see the table bending it is time to reconsider the push.


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## ShawnR (Nov 10, 2021)

I was not joking but perhaps there is a miscommunication. Good you had a laugh.

I was thinking we just wanted to note or measure deflection in the table under some load. Unfortunately, with a bottle jack, hard to quantify the actual pressure.  Rather than attempting to compensate for relative stresses in the rest of the press, why not just measure the beam deflection with a source independent of the press. Maybe I misunderstood. 

As mentioned above, I barely contacted the table and the dial indicator started moving.


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## ShawnR (Nov 10, 2021)

Further down the hole we goooooo....


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## Susquatch (Nov 10, 2021)

ShawnR said:


> I was not joking but perhaps there is a miscommunication. Good you had a laugh.
> 
> I was thinking we just wanted to note or measure deflection in the table under some load. Unfortunately, with a bottle jack, hard to quantify the actual pressure. Rather than attempting to compensate for relative stresses in the rest of the press, why not just measure the beam deflection with a source independent of the press. Maybe I misunderstood.
> 
> As mentioned above, I barely contacted the table and the dial indicator started moving.



Well ok then. You were serious. In that case you will learn something so it's all good.

Unfortunately, you cannot hope to measure the beam deflection if you try to measure it relative to an independent location. All you will be measuring is the collective sum of relative movements in the entire press. You MUST measure the bending relative to the plates anchored ends. I suppose you could do it your way, but you would need 3 independent indicators. One at each end of the beam and one at the center and then do some fancy vector math to subtract out the ends. But even then, there will be unaccounted for movements outside the plane of the plates bending. If you doubt this, use your same setup to measure movement at the pins. You will find that they moved too. But there are lots of ways to skin the cat. Put a bar across the plate from side to side on v-blocks. Put another block in the center but with a small gap. Use an indicator to measure the gap change. Make sure that you use pins or vblocks at the ends so the reference bar itself does not bend.

But either way, the plate will start bending the moment the ram makes contact with it so that result is indeed correct.


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## 6.5 Fan (Nov 10, 2021)

All i know is if you build a press based for a 10 ton jack and your nephew puts a 20 ton jack in it things will bend, the bent top structure will not spring back to the original position.


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## Susquatch (Nov 10, 2021)

ShawnR said:


> Further down the hole we goooooo....



I like this. I might make one! But I won't waste a perfectly good bar of aluminium. I'll just cut the caliper apart and use it. It already has the oil hole. And the bore is already the right size for the piston. I don't believe a big stroke is needed. Maybe it could even be turned to "look pretty"!  Just fill the piston cavity with oil (or even brake fluid), and install a very high pressure gauge the area of the piston and pressure reading can be used as I described earlier to measure the force. Psi x area = force.

Edit - I found two old brake calipers in my scrap pile. They might prove to be too rusty to pull apart, but I'm gunna give this a try. Ive also got a few 4000 psi pressure gauges that I use when I'm working on tractor hydraulics. I've always wanted a load cell!


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## ShawnR (Nov 10, 2021)

Susquatch said:


> Well ok then. You were serious. In that case you will learn something so it's all good.
> 
> Unfortunately, you cannot hope to measure the beam deflection if you try to measure it relative to an independent location. All you will be measuring is the collective sum of relative movements in the entire press. You MUST measure the bending relative to the plates anchored ends. I suppose you could do it your way, but you would need 3 independent indicators. One at each end of the beam and one at the center and then do some fancy vector math to subtract out the ends. But even then, there will be unaccounted for movements outside the plane of the plates bending. If you doubt this, use your same setup to measure movement at the pins. You will find that they moved too. But there are lots of ways to skin the cat. Put a bar across the plate from side to side on v-blocks. Put another block in the center but with a small gap. Use an indicator to measure the gap change. Make sure that you use pins or vblocks at the ends so the reference bar itself does not bend.
> 
> But either way, the plate will start bending the moment the ram makes contact with it so that result is indeed correct.



Yep, I know nothing. But I see what you are talking about now. The true deflection is relative to the ends. I will experiment tomorrow.


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## ShawnR (Nov 10, 2021)

Susquatch said:


> I like this. I might make one! But I won't waste a perfectly good bar of aluminium. I'll just cut the caliper apart and use it. It already has the oil hole. And the bore is already the right size for the piston. I do n't believe a big stroke is needed. Maybe it could even be turned to "look pretty"!  Just fill the piston cavity with oil (or even brake fluid), and install a very high pressure gauge the area of the piston and pressure reading can be used as I described earlier to measure the force. Psi x area = force.
> 
> Edit - I found two old brake calipers in my scrap pile. They might prove to be too rusty to pull apart, but I'm gunna give this a try. Ive also got a few 4000 psi pressure gauges that I use when I'm working on tractor hydraulics. I've always wanted a load cell!


Another site I found just used the short ram common in the frame porta power kits, the one like a hockey puck and installed a gauge where the hose fitting is. Of course, fill with oil and bleed (somehow). I have big chunks of aluminum from melting last winter so that part is easy (although I might question the quality of it. )


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## Susquatch (Nov 10, 2021)

ShawnR said:


> Another site I found just used the short ram common in the frame porta power kits, the one like a hockey puck and installed a gauge where the hose fitting is. Of course, fill with oil and bleed (somehow). I have big chunks of aluminum from melting last winter so that part is easy (although I might question the quality of it. )



I contemplated a warning about pressurized gas VS oil earlier in this thread, but decided against it. But if you are thinking about making your own cylinder out of cast aluminium, I have changed my mind. Pressurized oil (or other liquids relieve the pressure instantly when something breaks because they are incompressable. Gas can be compressed and therefore it can explode sending shrapnel everywhere at high velocity if something breaks. So if you decide to use your own castings, then make sure you bleed all the air/gas out of the system before building any pressure. This is VERY IMPORTANT.


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## ShawnR (Nov 10, 2021)

Susquatch said:


> I contemplated a warning about pressurized gas VS oil earlier in this thread, but decided against it. But if you are thinking about making your own cylinder out of cast aluminium, I have changed my mind. Pressurized oil (or other liquids relieve the pressure instantly when something breaks because they are incompressable. Gas can be compressed and therefore it can explode sending shrapnel everywhere at high velocity if something breaks. So if you decide to use your own castings, then make sure you bleed all the air/gas out of the system before building any pressure. This is VERY IMPORTANT.


mmm...interesting. Thanks for the heads up. I probably would have put up a shield anyways but now will definitely take precautions. Thanks


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## whydontu (Nov 10, 2021)

now we can go down the rabbit hole of Newton’s laws. The spring from the dial indicator also deflects the beam. Millionths of an inch, but maybe Dan Gelbart could measure it!


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## ShawnR (Nov 10, 2021)




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## ShawnR (Nov 11, 2021)

Modified the table as suggested by @Susquatch


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