JHCC

Converting an inverted hydraulic press into a light-duty forging press

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With a ruler, I get 9/16-18, but I want to check with an actual nut before I start ordering anything. 

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Okay, I’ll admit when I made a mistake: I remeasured the bolt once I removed it, and it IS 5/8” diameter. Oops!

However, I have confirmed that the pitch is 18 tpi. I’ll need a bolt at least 14-1/2” long. 

It seems that Fastenal carries a 5/8-18 x 15” grade 5 bolt for $24.61 each. I’ll keep looking for proper tie rods, but I do at least have a fallback plan. 

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Ouch, works out to almost exactly double what you payed for the rest. Just remember what you're getting for the price, I'd expect to have to spend $1,000 +. 

Frosty The Lucky.

 

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Welded on the upper die holder and the stiffeners:

AD2E1471-838D-44EA-BB9C-8CDE76E78EF0.jpeg

As well as the spacers on the sides:

7454CD7B-DC8A-4072-BBF5-916E30EFCDFF.jpeg

And added a bolt to hold the saddle to the bottom guide:

DB3ADC03-EE41-4FA5-B5B4-31462FF3468B.jpeg

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It's starting to look pretty Presscious John.

Frosty The Lucky.

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My own....

Here’s a view from the top, showing the stiffeners:

49B40283-ED25-4FEF-9F24-309A1B033469.jpeg

 I’m having trouble drilling out the cylinder mounting holes, and the full 5/8” is going to be beyond the capacity of my 3/8” drill. I’m going to have to see if anyone I know owns a 1/2” drill they’re willing to let me borrow; I know that I can get a sufficiently large bit. 

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I have the bites & drills that would make your job easier  

So, how many guys plumb in pressure gauges to see what operating pressure they are running at? Seems like a no brainer for pressing out bearings and such, or for cold steel work. Maybe it’s not a big deal for hot work?

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Thanks, Tom. I’ll plan on it. 

I’ve seen a number of presses with pressure gauges, but I’m not planning to add one to mine. 

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I don't recall seeing a forge press with a gauge on it and outside of watching down pressure the draw psi when breaking casing loose drilling we didn't pay much attention to the gauge at all.

I'm pretty sure forging you push it till it's far enough or the bypass opens. There's a reason "escape over bypass" squeals, it'd be easy to make that valve reasonably quiet but it's a good indicator the hydraulics are maxed. 

Frosty The Lucky.

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15 hours ago, Frosty said:

Just remember what you're getting for the price, I'd expect to have to spend $1,000 +. 

That's about my estimate of what the motor, pump, and cylinder would have cost me new!

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18 hours ago, Frosty said:

Ouch, works out to almost exactly double what you payed for the rest.

Well, if you add up the original cost of press with what I paid for the C-channel and a spool of welding wire (I already had the rest of the steel, most of which was free salvage), that's about the same as what those four bolts would be. That's why I'm still looking for an option that is both equally strong and less expensive.

This brings me back to an earlier question that never quite got answered. I totally understand that I should not be using ungraded all-thread, but I was wondering if there was any difference in proof strength between a bolt and a threaded rod of the same grade. I posed that question to a fellow at a bolt manufacturer in Oregon who told me, "A grade is a grade, and a bolt is going to break on the threaded section regardless of whether it's a partially threaded bolt with a head or a headless bolt with thread all the way." If that's the case, why not use a high-grade threaded rod?

According to the Engineer's Toolbox, 5/8" fine thread bolts have a proof strength of 14,100 lbs (7.05 tons) in Grade 2, 21,800 lbs (10.9 tons) in Grade 5, and 30,700 lbs (15.35 tons) in Grade 8. I haven't yet found a proof strength for B7 bolts, but one chart gives its clamp strength (75% of the proof strength) as 20,157 lbs, which would give it a proof strength of 26,876 lbs (13.438 tons).

McMaster Carr wants $19.48 for a three-foot B7 rod and $8.49 for a 25-pack of grade 8 nuts. That would be a total cost of $47.45 (+S&H), which is less than half the cost of the bolts from Fastenal. If the strength is the same, is there any reason other than "All-Thread BAD!" not to go with the less expensive option?

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43 minutes ago, JHCC said:

$8.49 for a 25-pack of grade 8 nuts

Or $8.28 for a 25-pack of grade 2H heavy hex nuts, which might be preferable..

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In tension I would agree with that, a bolt is only as strong as its weakest point. In shear it’s a different story.

By heavy do you mean longer/taller, or thicker? A long nut would give you more surface area and wouldn’t hurt at all if you can make it work. 

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In shear, definitely, but all the force on this will be tension, right?

"Heavy hex nuts" are both thicker (along the axis of rotation) and wider (across the a-of-r) than regular nuts and are designed for high-stress applications. The ones at McM-C are 20% bigger in both directions than their regular "high-strength" nuts.

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In the mean time, I've spoken with customer service at Parker's cylinder division, and they were very helpful. They're going to cross-reference my specs against their standard part lists, so I can get a quote from a local distributor.

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Update: Parker came through with a part number, local distributor contacted for quote.

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If all thread meets your specs + a margin then use it. I just have a thing about all thread, I'm prejudiced I've probably just seen too much used where it really shouldn't have. 

I'm happy to see guys with more experience than I in given areas jumping in.

I'm really liking how this is coming along. Good on ya John.

Frosty The Lucky.

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At this point, I'm wait-and-see mode to find out what price Parker comes back with. If the all-thread is substantially less expensive, I'll probably go that route.

And that brings me back to another question that was never quite answered: if I use all-thread (or indeed if there's enough thread on the end of the stock tie rod), can I fasten down the head cap with its own nuts and then fasten the entire assembly to the table with a second set of nuts? Again, here's the sketch:

02FB59D8-4942-4A6E-812F-0FD79803BECA.jpeg

The big advantage of this arrangement would be that the cylinder could be assembled completely and then attached to the table, whereas having one set of nuts holding the whole thing together would necessitate assembling the cylinder onto the bottom of the table (perhaps temporarily assembled and held together with a strap or something).

The nuts could act as the spacers necessary to clear the hump in the head cap for the port, or a separate spacer could be added (I'm inclined to the latter option).

Thoughts?

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I would say you definitely want to use a nut at the cylinder cap so you can torque to the proper spec, and then attach to the table top. I would also think lock tight would be a good idea on both the nuts holding the cylinder together. Maybe your contact at Parker can help you with that, and a torque spec.

Frosty - I would agree with in regards to big box quality all thread. I would absolutely not trust that in this application. 

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I just have a knee jerk reaction anytime someone says all thread. But the grade is the grade and all screws fail at the threads in tension. I'll rest on this one.

The piston shaft end is the cap that the tie rods screw into? 

I can't tell you how much I'd really prefer to drill and tap the table top to mount and secure the cylinder caps. Spacers and nuts on the tie rods works, can't argue my druthers. 

Glad you're handy Tom.

Frosty The Lucky.

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10 hours ago, Frosty said:

The piston shaft end is the cap that the tie rods screw into? 

No, the rods screw into the cap at the back end, the one with the clevis fitting. The holes in the head (the top end with the rod) are pass-through and unthreaded; there are nuts screwed onto the top ends of the tie rods:

51F3FCC1-CF2A-4216-B2AA-1A6993BF1899.jpeg

11 hours ago, Fowllife said:

I would say you definitely want to use a nut at the cylinder cap so you can torque to the proper spec, and then attach to the table top.

10 hours ago, Frosty said:

Spacers and nuts on the tie rods works

Thanks, guys. Much appreciated. 

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Without knowing the rating and specs of your bolts and nuts, I'll just offer some minor advice, where I am, [Australia,], metric bolts and nuts from commercial grade, [4.6], are not interchangeable with h.s, [ 8.8] grade bolts and nuts, the 8.8's being ever so margionally looser on 4.6 threads, many times while trying to fit column base plates on holding down bolt threads,[ 4.6]  that had been damaged and the nuts would not start, all it took was to run a 8.8 nut on, and either leave it on, or take it off and replace it with a 4.6 now that the thread was a bit better, a bit like a poor mans die nut. This was much more obvious on galvanised bolts.

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10 hours ago, Frosty said:

I just have a knee jerk reaction anytime someone says all thread. But the grade is the grade and all screws fail at the threads in tension. I'll rest on this one.

Not to worry. I’ve learned more about bolt grades and stress calculations than I would have otherwise, so it was definitely not a waste of time. 

8 hours ago, Dasher said:

Without knowing the rating and specs of your bolts and nuts, I'll just offer some minor advice, where I am,

Interesting. Duly noted. 

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