Anyone know the torque output of the auger drives?

[Clumber]

If you have the auger drives for the PT-425:
T3219 - Post Hole Digger Head (Pivot)
T3301 - Planter Drill Head (Fixed),

Do you know the torque output. I asked PT. They just said the that the torque in both units is sufficient to drive all the augers listed in the T8 price list. The answer is kinda useless when you are trying to compare third party units. I do not know the motors used in these products.

See the What is the down force of the PT-425?thread for details on what I'm trying to do.

 

[J_J]

Just some figures I worked on.

With 8 GPM driving a hyd motor, of 10 cu in, the rpm would be 185.

A hyd motor of 10 cu in, working at 3000 psi, will have torque around 4,777 in lbs.

If you were to rotate a hyd motor full of fluid, one revolution, the fluid coming out would represent the cu in displacement of the motor, or close enough.

 

[J_J]

Carl used a 28.3 cu in hyd motor.

Top speed would around 160 rpm, and torque around 9700 in lbs.

 

[Clumber]

I am trying to compare the PT auger drive units to alternatives such as the Danuser drive units for Mini Skid Steers. See the link:
Auger Drive Units | High Pressure Auger Drive Units | Danuser Machine. Scroll down to the MD-615. It can take 8 GPM and output 1299 ft lbs of torque at 47 RPM. I have looked at many others and this seems the best torque, 1299, that I could achieve with an 8 GPM flow. The MD-615 is about $400 more that the PT drive units. However, I can't compare them because I don't know the torque of the PT heads...

I looked at the low speed/ high torque motors at Surplus Center. The motors that take less than 10 GPMs are in the 5 Cu in category and do not generate adequate torque.

 

[Marks481]

Bottom line, faster motor = lower torque (inverse linear relationship). Trade off one for the other.

But the power source is the same; same supply pressure and flowrate, so you really shouldn't see any differences between the products you are comparing. The hydraulic motors are all going to have similar efficiencies, the only wild card being that differing displacements drive different speeds.

I run my auger at full rpm on my PT422, and find that it runs at a good speed. In damp soil with minimal rocks, it will punch a 3' 8" diameter hole in about 45 seconds (in VA). In the rock filled land of CT, in dry soil on the one hole where I was lucky not to hit a rock it took about 2 minutes to drill that hole. The other 10 holes where I hit rocks ranging from softballs to V8 engine size, those holes ranged from 10 minutes to a whole afternoon excavating a large boulder. The picture at left is 1/3 the size of said boulder.

The PT auger will not break up rocks. If you need an auger that will, I suspect that your PT425 will not be able to handle it. What is the soil like around your house?

 

[J_J]

I am trying to compare the PT auger drive units to alternatives such as the Danuser drive units for Mini Skid Steers. See the link:
Auger Drive Units | High Pressure Auger Drive Units | Danuser Machine. Scroll down to the MD-615. It can take 8 GPM and output 1299 ft lbs of torque at 47 RPM. I have looked at many others and this seems the best torque, 1299, that I could achieve with an 8 GPM flow. The MD-615 is about $400 more that the PT drive units. However, I can't compare them because I don't know the torque of the PT heads...

I looked at the low speed/ high torque motors at Surplus Center. The motors that take less than 10 GPMs are in the 5 Cu in category and do not generate adequate torque.

If you used the same hyd motor as Carl, 28.3 cu in, and pumped 8 GPM through it, it would turn at 65 rpm and have torque around 13,519 in lbs.

 

[Clumber]

Bottom line, faster motor = lower torque (inverse linear relationship). Trade off one for the other.

But the power source is the same; same supply pressure and flowrate, so you really shouldn't see any differences between the products you are comparing. The hydraulic motors are all going to have similar efficiencies, the only wild card being that differing displacements drive different speeds.

I run my auger at full rpm on my PT422, and find that it runs at a good speed. In damp soil with minimal rocks, it will punch a 3' 8" diameter hole in about 45 seconds (in VA). In the rock filled land of CT, in dry soil on the one hole where I was lucky not to hit a rock it took about 2 minutes to drill that hole. The other 10 holes where I hit rocks ranging from softballs to V8 engine size, those holes ranged from 10 minutes to a whole afternoon excavating a large boulder. The picture at left is 1/3 the size of said boulder.

The PT auger will not break up rocks. If you need an auger that will, I suspect that your PT425 will not be able to handle it. What is the soil like around your house?

The frost line here is two feet. The soil here is mostly about 6" of topsoil followed by hard clay and/or shale fragments. The shale can be white (ground hog shale which crumbles to a white powder when chipped) to a more difficult red shale. We usually hire a neighbor with a 3pt PHD with lots of HP but little down force. The PHD digs about 6 to 8 inches then its manual chipping or using a 60 lb electric jack hammer for 1 to 3 inches them the PHD for a few more inches ... We usually end up with a depth of 1.5 feet then use cement... We mostly use 4" PT posts and oak board fencing.

I was thinking that a combination of a Danuser wobble auger and a cast auger with aggressive teeth is needed here. We also have section of what looks like limestone. It will be either the jackhammer or a rook auger to deal with the later.

Can you determine the model of your auger drive motor??

 

[Marks481]

If you would liKe, you can stop by and borrow my auger (8" bit) next time you are in town and give it a try at your house. I am not using it at all, so you could keep it for a few weeks until the the next time you swing by my way. You could see if the stock PT auger would work for you, or if you need something different.

I think that it is probably the auger bit (vs the motor) where you can improve on the performance the most. I think that the PT auger with its rounded point might not work as well as some other types, especially te kind that has somethingthat looks mr like a screw point on the tip. You are welcome to give it a try. While the PT is probably better at getting downward force then a 3pt auger, I suspect it might not have much more luck in your soil type. Still, you will never know for sure until you try.

 

[Clumber]

If you would liKe, you can stop by and borrow my auger (8" bit) next time you are in town and give it a try at your house. I am not using it at all, so you could keep it for a few weeks until the the next time you swing by my way. You could see if the stock PT auger would work for you, or if you need something different.

Thanks for the offer Tim. Best idea of the day. I will PM you to discuss a time.

 

[Clumber]

Tim, What is the size of the your bit interface, 2" Hex, 2" round, or 2-9/16"?

 

[Marks481]

I am away on travel right now, but it is the standard PT auger, which I think is 2 9/16" (2" seems way too small, and it definitely is not a hex drive). I will take a look when I get back on Friday.

 

[Red Zebra]

I purchased the auger and 6" bit from PT. Later bought a 12" from Tractor supply. I'm in TN with very hard clay (when dry) with rocks ranging up to 4" on most parts of my property. Sometimes find larger flat rocks which the auger will break or break loose if not too thick.
.
The 6 and 12" will bore with no problem during the driest (sp?) conditions. I usually run at 1/2 throttle. You can feel it hitting rocks, and bringing them up to the top. Not sure how shale compares but I found letting the auger "do it's thing" while applying "just enough" down pressure will usually get the job done. The trick is take your time and let the auger do the work. It sure beats hammering and post hole diggers. We have mainly used the 12" to dig holes for 1 gal plants.
Hope this helps. BTW, the TSC bits fit perfectly into the auger reciever--at 1/2 to 1/3 the price of PT.
'
Have no idea what the torque output is but as I explained to my wife, always stand clear of the auger--if it grabs you, it won't let go and it'll wrap you up on the bit. At 1/2 throttle, the motor barley changes pitch as it bores--taking about 1 minute for a 6" hole 2-3 ft deep.

 

[Clumber]

I purchased the auger and 6" bit from PT. Later bought a 12" from Tractor supply. I'm in TN with very hard clay (when dry) with rocks ranging up to 4" on most parts of my property. Sometimes find larger flat rocks which the auger will break or break loose if not too thick.
.
The 6 and 12" will bore with no problem during the driest (sp?) conditions. I usually run at 1/2 throttle. You can feel it hitting rocks, and bringing them up to the top. Not sure how shale compares but I found letting the auger "do it's thing" while applying "just enough" down pressure will usually get the job done. The trick is take your time and let the auger do the work. It sure beats hammering and post hole diggers. We have mainly used the 12" to dig holes for 1 gal plants.
Hope this helps. BTW, the TSC bits fit perfectly into the auger reciever--at 1/2 to 1/3 the price of PT.
'
Have no idea what the torque output is but as I explained to my wife, always stand clear of the auger--if it grabs you, it won't let go and it'll wrap you up on the bit. At 1/2 throttle, the motor barley changes pitch as it bores--taking about 1 minute for a 6" hole 2-3 ft deep.

Thanks for the info. Your note along with the other responses were very helpful. I am leaning towards the PT Tree auger (has more torque). However, I still want to know if there is a significant difference in torque compared to a Danuser MS-615 mini skid steer unit. Can you please read the label on the motor and post the make and part number? Thanks

 

[woodlandfarms]

I just have to say again that building mine, all in, was half the price of PT. Very very easy build.

Carl

 

[J_J]

As far as torque goes, there are some assumptions one can make.

With 8 GPM's and with an average speed of 154 rpm, then the displacement would be 12 cu in. With 12 cu in and 3000 psi, the torque would be about 5,732 in lbs.

So if you wanted more torque, and less rpm, you could go with a larger displacement hyd motor, say 20 cu in, and with 8 GPM's and a 20 cu in motor, and 3000 psi, you would have a motor rpm of 92, and 9,554 in lbs for torque.

 

[J_J]

Carl,

Did you figure or measure the rpm of your motor.

 

[woodlandfarms]

Carl,

Did you figure or measure the rpm of your motor.

No.... I have no clue hoe. It does not seem very fast. I doubt much more than 120 rpm at full throttle.

 

[Red Zebra]

Can you please read the label on the motor and post the make and part number? Thanks

It has only a Power-Trac label and s/n on it.

 

[Clumber]

It has only a Power-Trac label and s/n on it.

Thanks very much for looking.