Post Holes 1845c vs Mini Track

[firecatf7333]

I own an 1845c and a bobcat MT 55 with a post hole auger. The auger faceplate won't fit on my 1845c....so i'm considering renting a auger for a bigger job with 100+ holes.

The MT 55 is more powerful than your typical dingo or other mini. Here are the specs

2011 MT 55- 12 GPM and 25 HP

1995 1845c- 16 GPM and 60 HP


So the Case has more than double the HP and about 33% more Hydraulic Flow. The MT 55 drills holes very well when the soil is sandy but when I hit bigger rocks the MT 55 doesn't have enough Hydro flow and the auger will just stop. Do you think the 1845c will be much better? Does horsepower really matter when drilling holes or is it all about hydro flow.

Thanks for the help.

 

[KSSS]

The short answer would be, the more difficult the ground conditions, the more you would want the 1845C. Post holes don't take a lot of power in easy conditions. This is evident by the hand operated post hole drillers that are powered by a small gas engine.


The longer answer: As conditions get more difficult, it takes more to dig the holes. There are a couple variables at work. The Post hole auger: Some have gear reduction to increase the torque of the bit. Also make sure the teeth are in good condition. The host machine itself: The relief settings on the host machine at the aux. circuit are important. I believe the psi on the 1800 series machines was 2500 psi. Rocks can stop any auger but the higher the relief settings the more perceived digging power you have. One of the biggest advantages of the skid steer over the MT55 is the down pressure. GPM is also important as it allows you to dig faster and cleans the holes out better. There are some tricks you learn which makes digging the holes more effective. Wet material digs much better than dry especially if there is a lot of rock. In heavy rock you can dig at a slight angle to dislodge the rock and then straighten the auger back to plumb to break free heavy rock. I have dug countless holes with 1800 series machines, and they work well. I would probably rent the attachment if there is any concerns of the ground conditions being anything but easy digging.

 

[firecatf7333]

Thanks KSSS your always quick to reply. I've gotten pretty good with holes using the MT for the past 3 years. I've never used my 1845c for holes b/c I leave it 15 miles from my house. Will see how it works as I'm going to bring both machines and try that. The 1845c has a relief pressure psi of 2300...while the MT 55 has a relief pressure of 2900. Does this mean that the MT 55 actually has more hydro pressure? 2900 psi is direct from bobcat site and 2300 psi for 1845c was from bcrentals?



Also....would it be possible to get a better auger drive unit with more torque? I wouldn't mind a drive unit that went slower if it would chew through rocks with a rock bit

thoughts

 

[KSSS]

I have a customer who does tempory wind towers to measure wind speed for windmills. He needed to spin in anchors to a certain torque rating. I researched the different post hole power heads and there is a lot variation in torque ratings. There is also some pretty advanced heads out there much to my surprise (you can dial in the torque spec into the head). So doing some research could pay off for you.

The BC makes more psi, but the overall weight, downpressure and gpm of the skid steer would still make it more productive in tough conditions in my view. Pretty sure that the 1845C had 2500 psi from the factory.

 

[firecatf7333]

Ideally....The MT55 works good for everything I do...unless i'm drilling holes in rocky ground. I'm wondering if I could get a different drive auger for the MT55. Something that spins slower but would have more torque, and then also get a rock bit. I'll have to find out if a low torque auger drive unit will work the MT55. It would take longer to drill a hole in easy soil...but that's not a concern for me.

Check out this auger drive unit

http://www.youtube.com/watch?v=lPUbT7Fc04o

 

[roadrunner81]

I would not use any more of my time to think about the mt55. You could rent an auger for a day or two and have all your auguring done. I augured over 5000 holes for a job in terribly hard glacial till. As the carrier gets lighter you have less control and machine will bounce around more making for a long day. This was between a 9900lbs machine and an 11500lbs machine

 

[firecatf7333]

It's not just this one time. I'm doing more pole barns now and will be doing more holes. Average holes are 20-35 holes per job. Basically it comes down to the MT55 or using 1845c(which is a pain b/c it's not at home)

 

[roadrunner81]

Are your jobs at home? If not time is money and augers are not that expensive.

 

[firecatf7333]

We have 210 holes to drill with a 24" auger. I think i'm going to rent a Larger Skid steer. The next issue I ran into today on a different job will be frost. We rented a air compressor and 90lb jackhammer but even that took too long.

We will have a telehandler and the skid steer we rent on site. Would the telehandler or skid steer drill holes better? Will a jack hammer attachment on either the skid steer or telehandler work good to drill through 1-2ft of frost? I've never ran a telehandler so I would prefer to auger drill the holes with the skid steer.

Thanks

I've read about hay bales and coal but that seems a lot of work for 210 holes. Would putting 1-2 ft of hay over each hole a week b4 we start the job work good? This job won't happen until jan.

 

[frogfarmer]

This may not be an option but I have used a CTL to auger through frozen ground and ice in the past. I also have used a rubber tired skid but the CTL had much better down pressure due to the design and weight of the track setup. In very hard ground we use a much smaller auger 6" or 9" depending on what we have and then final drill to size. A heavy duty 9" rock auger will make a fairly large hole much larger than 9" if you work it back and forth. Havent had to use a breaker to get holes in the ground and I doubt that the hay alone would be much help. Another option would be high pressure water and a suction tank. We have used this method around sensitive cables but works well in frozen ground if you keep the water warm. 210 holes will take quite a while with this method.

 

[firecatf7333]

Yes we will most likely rent a CTL, but the holes are going through a gravel pad. This is like concrete and I don't see a CTL going through this. The holes need to be opened up about 12" before a auger bit will "bite" and start the hole.

Another thing we could do would be to rent a jackhammer for our Bobcat MT 55, and then follow behind each hole with the CTL.

 

[KSSS]

Frost 2' will be a challenge even with a breaker since the breaker wont be able to get that deep. Be sure you have carbide teeth on the post hole auger. I have used a weed burner to thaw the ground in the past on frozen ground. It all depends on how hard it is as to how long it can take. My advice would be to use whatever tool carrier that will give you the most down pressure.

 

[frogfarmer]

You know your walk behind much better than I do but my limited experience with them hasnt been impressive. A breaker on a skid or backhoe will make quick work of frozen ground or gravel. Around here we have alot of granite and have rock augers for the tough jobs. The rock augers are extremely heavy duty and have multiple replaceable points that engage the rock. Whatever you decide it sounds like the conditions are not ideal.