I have a new Kubota M8560 that I am considering purchasing a post Driver for. I have a lot of horse fencing to do with 6-8 inch pressure treated posts. My ground conditions here are pretty hard. There is a lot of shale (fractured rock) and so augers have failed to do the job. I had a contractor here who did some work with a driver and I believe it to be a better option.
I'm looking into a used Shaver HD-12 post driver. I think it has the power I need. The question is, will it work with my tractor? The driver is hydraulic driven (not PTO) and it hooks up to the 3pt hitch (cat 2). The spec's on Shaver's website call for 15 GPM @2000 psi to operate it.
From what I can tell, my M8560 has 17GPM "at the utility implement pump" I assume this to mean that the pump runs the hydraulics for both the 3pt hitch and the accessory hydraulic jack at the back. Since I won't be using both simultaneously, this set up seems like it will work right? I also wasn't able to find the psi of the rear hydraulics to make sure it was >2000.
Kyle,
The Shaver HD-12 will work fine on your tractor. The hydro capacity is NOT used for driving the posts. The post driving action comes from the weight of the falling ram and from the springs that pull down on the ram. The hydraulic power is only used to raise the ram upwards. If you have an undersized hydro pump, the ram will simply lift slower.
I have an L4760 and I bought a very used Shaver HD-8 - the smallest one - and I fenced a new pasture with a mix of 5" and 6" round cedar posts, non-tapered, and non-sharpened. Most of the time I ran my tractor at idle - which means minimum pump power.
If I throttled up the engine, the ram would lift faster because of the increased hydraulic flow, and this could make the job go faster, but I found that if I went too fast I started driving posts crooked.
On my tractor with the HD-8 unit, running at idle power, lifting the ram to full height after a hit only takes about 1 second. Running it faster is honestly pretty scary
One note: you use a normal hydraulic rear remote quick coupling to SUPPLY the post driver, but the RETURN line from the post driver can have no restrictions at all. You can not tie it back into the remote-return port on your rear hydraulic remote. The "ram" operation evacuates the hydraliuc fluid out of the lift cylinder as quickly/violently as possible, and if you try to force the fluid through small hydraulic fittings, you just lose ramming power.
Instead of using a rear remote, you route the hydraulic return line directly into the hydraulic fill port on your tractor. On the L series, that's a rubber plug that goes into the back of the transmission. The opening isn't threaded and there isn't anything near by to firmly attach the return line with, so on my tractor, I used some galvanized pipe fittings on the end of the 3/4" hyd return line to "rest" it inside the transmission fill port. Each drop of the ram would tend to make the return line work its way out of the transmission, so I had to keep an eye on it and stuff the pipe back down there.
I don't know what the M series is like, but routing the return line will be something you need to figure out.
Here is a picture of my setup, to try and make it clearer:
https://onedrive.live.com/redir?res...authkey=!AHhP0yQmHjfUmqA&v=3&ithint=photo,jpg
You can see that only 1 hose goes to the rear remote - it is a normal 1/2 line. You can also see the bigger 3/4" return hose dumps into the back of the tractor's transmission.
Oh, that reminds me. You'll need someway to hold the tractor's hydro valve OPEN when you want to operate the post driver. The driver has its own valve that raises/empties the ram, that you operate while standing out behind the tractor. However, that only works if the tractor is supplying pressure to the post driver, and on my tractor, someone has to be in the cab holding that hydro remote lever forward.
In my case, once I was sure I had the post driver aimed properly, I used a box end wrench to wedge the hydro lever in the cab into the open position. I am sure you can come up with something more elegant!
Overall, I really recommend the Shaver HD post drivers. I started my fencing project using a PTO auger and it was miserable. It took me 2 hours to do 4 posts, and I was dead tired after all of the tamping. For my effort, I got posts that weren't precisely placed and were absurdly loose.
After the misery of those 4 augered posts, I bought a used post driver and never looked back. I finished the rest of the 60+ posts with the Shaver. That includes driving posts into berms, in the woods, when the tractor is up higher than the driving surface, etc. The Shaver setup is really slick. My local farm store had all the stuff I needed to replace the hydraulic lines and fittings, and I bought a replacement cap/seal from Kencove that I haven't installed yet.
Best of luck,
Matt
