Upgrading Harbor Freight 20-ton Press to Air

[SteveHGraham]

Now that I have a finger brake on my press, I am already tired of pumping the handle. I have pumped it up and down well over 20 times, and I am exhausted, nearly to the point of slight perspiration. I got myself a Harbor Freight air jack.

Harbor Freight being what it is, they do not provide mounting holes on the base of the air jack. I lined the plate the old jack sat on up with the new jack and used a transfer punch, and the drilling locations don't really work for drilling all the way through. Stuff on the other side is pretty close to the holes.

I'm wondering if anyone else has installed one of these and would have some advice.

I see two possibilities.

1. Drill new holes in the press's plate as well as the new jack, all the way through both.

2. Drill blind holes in the bottom of the jack and use a bottoming tap.

[SteveHGraham]

I'm trying to find out if the jack will work upside-down. If so, attaching it to the upper member of the frame might be good.

[warmstrong1955]

I built my press from leftovers. I used a Northern Tool air/hyd 20T jack someone threw away for the sake of a bad o-ring. I'd guess my jack is probably out of the same factory as the Horror Freight creampuff.

You don't need to mount the jack base. I assume the press you have, has a plate with a hole or counter-bore, to hold the bottle-jack rod centered. That's all you need. The base of the jack will just set there.....and go up and down, and remain centered.
The jack has mounting holes, but I didn't see a need for using them, and haven't had the need, after years of use.

I made a handle for the valve too. Fitted with a light press to the valve, so it is always there.....and doesn't go anywhere.

And, no pics, but I made a foot pedal for the air valve. That way I can keep both hands on what I'm working on, which is especially handy forming parts and the like.
It's just some junk I threw together, with a bicycle brake cable my son never used. I should make something a little more sophisticated.....but what I have....works.

[warmstrong1955]

Here's the whole enchilada.....
You can see the early American foot-pedal.

[BadDog]

Yeah, I added an air jack to my old 20T years ago. I don't remember doing anything to mount it. I also made a small "hand wheel" (2" tubing 1/2" long formed the rim) for the release valve, but wasn't motivated enough to convert to foot pedal.

However, on mine the restraining plates that slide along the vertical were far too sloppy fit. So with a bit of scrap and welder I fixed that so it moved along smoothly with almost no movement when pressure applied. Basically added something like heavy-tack welded gibs.

[SteveHGraham]

This press has nothing on the bottom of the jack to hold it in place. Just warm thoughts and the two screws I removed today. The ram fits into a little cup on the upper member of the frame. Is that what you're talking about?

The air jack is fricking great. It works fine with my miniscule benchtop compressor. I'm thinking I might just fasten the compressor to the base I'm making for the press and dedicate it to mashing things. I could roll the press around and not worry about air lines. This old compressor is not doing all that well, and I was thinking about getting a new small compressor, so sticking it on the press would be better than Craigslisting it for $30.

I feel like going out to the shop and crushing things just because I can.

I'm looking around with an eye toward getting a 7.5-HP compressor. I have a 5-HP job, but it doesn't seem to keep up with everything at 17 CFM. Maybe I plumbed it wrong, but that's the result I'm getting.

Your press is pretty fancy with that crossmember that fits inside the frame. Mine has big hoops of steel that go around the uprights. I've seen some neat modifications for getting rid of them.

[warmstrong1955]

Yeah, I added an air jack to my old 20T years ago. I don't remember doing anything to mount it. I also made a small "hand wheel" (2" tubing 1/2" long formed the rim) for the release valve, but wasn't motivated enough to convert to foot pedal.

However, on mine the restraining plates that slide along the vertical were far too sloppy fit. So with a bit of scrap and welder I fixed that so it moved along smoothly with almost no movement when pressure applied. Basically added something like heavy-tack welded gibs.

Being as how I started with a pile of H-beam, I made the sliding beam under the jack fit the inside if the verticals first, and used it to position the verticals both top & bottom. I didn't want a bunch of wobble, as I had planned, and do, broach with it. I do some than my arbor press won't handle, both in tons, and length.

[warmstrong1955]

Yes....the return springs hold the base of the jack to the travelling crossmember, both up and down. The 'cup', on the top, keeps the jack centered to the world.
Not enough spring??.....shorten the length between centers, or change/add more.
My return springs, are the ones that came with the NT jack, and they work great.

I haven't used a Horror Freight press much. Had some friends that had one.
If the travelling beam didn't track straight with the verticals, I would add some iron so it did, but the springs, if they have enough pull, should do that, especially when you consider the width of the base.
And the base, is always parallel with the ram end.

[BadDog]

Yeah, a press has to be stable to be functional (and safe). I hate when pressure starts rising, and it shifts... I've got a piece of 3/4" plywood (basically an old shelf about 2' x 4') that I place between myself and my current 50T when things start getting real.

On a related note, my current 50T unit has a nice setup on the press head that works somewhat like common arbor presses. From memory, it's basically a 2" round solid some inches long with a 1" bore in the end about 1" deep. There is a thumb screw that protrudes into the bore at about the 1/2" mark. That allows me to make various tips for it. Just turn a 1" x 3/4" spud with a small groove about 0.5" up a bit wider than the thumb screw to hold it in loosely. It basically just keeps it from falling out when lifted, and when pressing it rests on the shoulders. As such I can make long fingers to get around things, big wide face, whatever.

[SteveHGraham]

The press now has 4 springs on it. Two came with the press, and two came with the jack. Seems to me I should continue using all 4. They don't hurt anything, and people say the extra tension makes the press retract quicker.

I may put some screws in the jack eventually, just to make myself feel better. thanks for the tips.

[warmstrong1955]

Stuff shifting is a pain. Shifting when broaching, could be downright deadly.

Just looking at the Horror Freight website, it looks to me that they have a very short bearing area with those 'ears' on the traveling beam.
Mine is 4", and I figured if it wasn't sufficient to keep things from moving around, I would add to the area. Easy enough with a little flatbar.

What you describe, sounds much like how I built mine.
If you look at the pics I posted, you can see the fancy-dancy thumb-screw, also known as a 3/8"-NC bolt, and the shiny short tip in place. On the top of the press at the center, is one of the longer, but narrower ones I built.

[warmstrong1955]

I just have the two springs, and it works fine.
When I built it, it would almost-just-about-not-quite-but-nearly... retract all the way when released.
I drilled a couple new holes on the top spring mounts. End of problem....that's all it took.
It doesn't take much.