Hydraulic jackhammer for tamping dirt around post holes?

Fallon · Apr 19, 2016

I'm part way through putting in a new fence. I've got a nice 3pt quick hitch hydraulic toplink setup along with a 200lbs weight ontop for my PHD, so it only takes me a minute or so to dig the holes. We usually spend another minute or 3 with the clam shell post hole digger pulling some loose dirt out of the hole. The killer is always tamping the dirt back into the hole after we dig it. I'm putting in a cross piece between the posts that fits into the holes at the top of the posts, so I can't pound the posts in. I need to lean the new post over 6" or so to put the cross piece in.

At any rate I've seen a few hydraulic jackhammers on Craigslist for $150-400 or so & was wondering if anybody had ever used one instead of a tamping rod to tamp the dirt back into a post hole. I'm hoping it would work & save our shoulders from that dam tamping rod that is killing us now. I assume I'd probably have to modify an existing bit & put a flat or mushroom head on it, but I've got a welder & plasma cutter to jurry rig something. I've got a spare spool on the tracotr & about 8gpm of flow, which is on the low side for the specs I looked up, but still within specs for the jackhammer.

Worth pursuing? Waste of time? Will manhandling & fiddling with the jackhammer be more work than the tamping bar?

oldnslo · Apr 19, 2016

What does the hammer weigh and how long would the hoses have to be. I can see fighting the hoses as a potential problem.

jeff9366 · Apr 19, 2016

Add a modest amount of dry concrete mix to the holes while installing the posts. After a rain the posts will be solid.

Streetcar · Apr 19, 2016

The jumping jack is a common compaction tool used in confined areas.
Tangled hose can be a problem

Fallon · Apr 19, 2016

Stanley BR37 hydraulic breaker is something like what I'm looking at. Just re-read the manual at http://www.stanleyhydraulics.ca/handheld/Br37-09.pdf & realized my 8gpm is optimum rather than minimum. It weighs in at only 37lbs.

I'm hoping hoses shouldn't be to much of a problem. The tractor is pretty much always within 10' of the hole or so. Typically as soon as I'm done with the hole I move the tractor out & away lined up with the next hole 8' away. I'm digging each hole as we go, given the relatively tight spacing requirements for the cross-bar on top. If I'm off by more than 4" or so with the hole, the cross-bar won't fit. I'm using a 12" auger & about 6" posts. Switched over from my 9" auger as it gave us more leeway to get the post properly positioned & room to tamp.

I've been avoiding concrete if I can so far. I'm a bit of a cheapskate (says the guy looking at buying a jackhammer) & previous posts I pulled I couldn't tell any difference between those with concrete & those without until I looked in the hole or saw the concrete come out of the ground. The concrete just didn't seem to do any better than the ones without on the old fence. I'm putting up 5' fence & using 8' poles, so my holes end up 30" deep (doesn't add up because there is about 6" above the cross-bar where I'm putting the fence up to). When we are tamping them hard, those poles don't wiggle at all when we get the holes half full. So I've been pretty happy with the tamped dirt option, other than the work.

Illini22 · Apr 19, 2016

You need a pole tamper that line crews use to tamp newly set poles.

Cataclysm · Apr 19, 2016

I have a Greenly hydraulic tamper. Works great off the Kubota k-008 mini-x (about 5.5gpm @2100psi) and the LS4155 (about 8.2gpm @ 2450psi).

Weighs about 30lbs. I have 25' of 1/2" line. Its not too hard to keep the lines organized while tamping and it does a great job.

It is one of those tools that will beat you up if you fight it. A little practice and you can run it most of the day and not be wore out.