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  #11  
Old 08-08-2017, 08:05 PM
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I see an awfull lot of work for only a 4 ton press.

Step back and take a good look at what you want to do with the press.

What size bearings to press ?

What size material do you want to bend ?

Get some tonnage figures and let's work from there.
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  #12  
Old 08-08-2017, 08:20 PM
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Make so it will take the 10ton ram too in case you ever upgrade your porta power.


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  #13  
Old 08-08-2017, 10:21 PM
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Quote:
Originally Posted by JohnBoy View Post
Well the capacity is shot to hell anyway.

It's only a 4t Porta power

Should be enough for that type of work anyway?

Given the lack of capacity I've downgraded the frame too, it's now coming from the resource pile as opposed to being bought

Main vertical 80x80x5 box, 100x15 flat for the legs
For the 4T I'd keep the original design in case you get a little larger Porta Power.
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  #14  
Old 08-09-2017, 07:09 AM
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Lots of feedback, digr's press link has been most informative.


In terms of it being small, yes that will limit it's usefulness definitely, but if I've little invested then it's not the end of the world. Maybe I'll decide once I have one that I have to have a bigger one, then I might make or buy a bigger one someday and keep it at the farm, but there's no way I have room for a H press at home.

In terms of height, it will have a leg across the back for lateral stability and that could be clamped into the vice.

attached is what I came up with last night. Not a single cut made, all offcuts just stacked on each other. I don't have the threaded collar either for the ram so will need a tube around it to laterally locate it.


Digr's link surprised me with the relative lightness of it, I had thought it would need to be much heavier to cope with the tonnage. The one critical dimension I'm not seeing is the wall thickness of the box.


The big question on this is how much deflection is tolerable in the box?

I used this website https://www.easycalculation.com/engi...ular-beams.php and made some assumptions about the position of the top holes in the frame.

I calculated deflection based on 5, 8, 10 and 12mm wall box sections.

800mm 200x150x5mm 25t .34mm
800mm 200x150x8mm 25t .22mm
800mm 200x150x10mm 25t .17mm
800mm 200x150x12mm 25t .14mm

I then put in my own options from the resource pile
500mm 80x80x5mm 4t .17mm
500mm 80x80x5mm 10t .41mm
500mm 100x100x5mm 10t .21mm

I think the 100x100x5mm box gives me a nice compromise that I can always stick a 10t ram into later, that .21 mm is 0.008 inches, surely not a big deal?
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Last edited by JohnBoy; 08-09-2017 at 07:30 AM.
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  #15  
Old 08-09-2017, 09:15 AM
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What size is the thread on the ram?
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  #16  
Old 08-09-2017, 09:48 AM
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Quote:
Originally Posted by Shade Tree Welder View Post
What size is the thread on the ram?
I have no idea, and i need to get a battery for my calipers to measure it.

It's a blackhawk 4 ton, I think they have a "standard" thread, but cant find it online

The ram toe part number seems to not have changed over the years so that's why I'm assuming the thread is the same.

http://www.shinnfuamerica.com/Produc...14/B65155/2215

Last edited by JohnBoy; 08-09-2017 at 10:02 AM.
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  #17  
Old 08-11-2017, 04:04 PM
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so this thread is the polar opposite of most I start.

Three days later I'm done, well almost.

I took a grinder to a piece of a loader grab I have had in the yard for years and cut a length of box. it turned out to be a very odd size, 93x93x6mm something I've never seen nor heard of. the 6mm could be 1/4 of an inch but the 93mm is weird, four inches is 3 2/3 inches.

It was also seamless inside, it's 80mm receiver tubing I guess. A pity to waste it on this job in a way, but hey ho it's what I had. Welded it together, put some braces on, and a support for the ram that still allows the ram to be removed.

Tried it out and was leaking at the fitting thread on the ram, a bit of ptfe tape sorted that and I pressed a bushing out, but now the cylinder doesnt seem to want to retract. there's air in there and I I can push the piston back a bit. I also think the pump tank might be empty, but I didnt have time to test any more.

Does it matter what sort of oil I put in? looks like ATF that's in it now if I had to guess.
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  #18  
Old 08-11-2017, 04:56 PM
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If it looks like ATF and it were mine It would get ATF and burp the air out and go at it.

Scott
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