I found daves but I stll cant find the one where I got the pic from I am starting to think maybe it was not from FSBPM Dave's Bronc 90. He fabbed a very nice hydro set-up that is powerful and fast, with more degrees per stroke of the ram.
Ok now I know what my next tool purchase will be, and on top of that I have spare pumps at work from our frame machines...:chili:Check out these hydro conversion brackets from Copperhead fab. They use that Harbor Freight air over hydraulic long cylinder you were asking about, and at $75 are WAY cheaper than my build was. As much as I love the hydro conversion that I built, I probably would have gone this way if it had been available at the time. They make one for the JD2 and a slightly different one for the PT105.
There is another guy over on Pirate selling a different style hydro conversion that uses a clamp on the cylinder instead of the long bracket that Copperhead uses, but I couldn't find it with a short search.
I don't have any experience at all with the air/hydro set ups, but I do have to say that I don't think you'll have any accuracy issues with this set up in particular. Reason being, that HF jack has a manual pump as well as the air pump. If you start to see that you're having problems with shooting past your mark when using the air, you can always just use the air to get close and then manually sneak up on the mark. Frankly I doubt that's a real problem, but the manual feature is still there. For that matter, if your compressor goes up in flames you can still use the manual pump. It looks like a nice set up to me. More compact than mine too.wow copperhead makes it stupid simple to convert... 150 bux and your hydro... ive heard that air/hydro can be a tad unpredictable and touchy, making it hard to be accurate... any truth to this??