Hydracore offers a combination of surface coring, underground coring, and custom fabricated drills for every need

Surface Core Drills

Hydracore Prospector

The prospector is the smallest machine in our standard product line. It can be made with a gasoline or diesel engine of 30 or 40 HP, and is capable of 300 feet B or 200 feet of N. Read more…

Hydracore Gopher Manportable

The Hydracore Gopher was the original manportable drill. It is designed to be quickly broken down into loads no heavier than 350 lbs. Gophers are rated at 1500 feet B or 900 feet of N. Read more…

Hydracore 2000

The Hydracore 2000 is one of the most versatile machines for core drilling. It is ideal for drilling N size holes to about 2000 feet, but it can also drill H size to 1000 feet or B size to 3000 feet. Read more…

Hydracore 2000 Manportable

The Hydracore 2000 Manportable is the combination of our Hydracore 2000 H size drill head, with our manportable powerpack. Read more…

Hydracore 4000

The Hydracore 4000 is the most compact machine of this capacity available. Capacity is rated at 5000 feet B, 4000 feet N, or 2000 feet H. Read more…

Hydracore 4000 Manportable

The Hydracore 4000 Manportable has the power of the Hydracore 4000 but in a package that can be moved on trails by men or ATVs. Some customers have drilled 6500 feet of N in very inaccessible sites with these machines. Read more…

Hydracore 5000

The Hydracore 5000 is the most powerful drill Hydracore makes. The Hydracore 5000 has the same P size head as the Hydracore 4000, but the feed frame is larger. Read more…


Underground Core Drills

Hydracore Gopher

The Hydracore Gopher Underground is made for mines where a lot of short holes need to be drilled quickly. Read more…

Hydracore 2000

The Hydracore 2000 Underground uses many of the same components as the Hydracore 2000 surface drill. The drill head, clamp, water pumps, mixers, and winch, are the same as on the surface 2000 drill. Read more…

Hydracore 4000

The Hydracore 4000 Underground is a bit more powerful than the Hydracore 2000 Underground. It has a P size head that makes it possible to drill P size or advance a lot of H size casing. Read more…

Drill Rod and Bit Charts

These charts have information that you cannot find anywhere else, about drill bit sizes, drill rod sizes, and constants that can be used to figure out drill bit and drill rod torque. There is also a chart for depth capacity of Hydracore drills.

Drill Bit Sizes

Drill Bit SizeO.D.I.D.Core AreaBit AreaMean Bit RadiusBit Torque FactorBit Torque as a Percentage of BO Bit Torque

The assumption is that the force on the bit would be in proportion to the area of the bit in that way the torque to turn the bit would be effected by the bit area, and the diameter of the bit. The diameter used to calculate the torque constant is the diameter mid-way between the outside, and inside of the kerf of the bit.

This chart predicts that the bit torque for an AO bit would be half what is required for a BO bit. An NO bit would require about double what a BO bit requires, and an HO bit is almost double an NO bit. On a machine like a Hydracore 2000 with a variable displacement motor or many other machines with gear boxes, the only way to get this extra torque is to slow the rotation speed down, either by gearing down or increasing the motor displacement. This chart gives a rough idea how much to slow down.

This chart also lists the bit area, in square inches, which can give you an idea how much harder you have to push on the different sized bits. The core area is also a useful measurement that allows you to determine the sample size.

Drill Rods

Drill Rod SizeO.D.I.D.Weight 10' RodRod RadiusDrill Rod Drag FactorDrill Rod Drag Compared to BO (%)

This chart uses the dimensions and weights of the various drill rods to predict how much torque is required to turn the different sized drill rods (in proportion to other sized drill rods). The frictional drag is assumed to be proportional to the weight of the rod times the radius of the dragging surface of the rod.

The chart shows that it will take about half as much torque to turn an A size rod string as a B sized one. This does not mean it will take half the horsepower, because an A rod string usually has to turn faster as well.

The chart predicts that it will take 24% less torque to turn a BOTK rod string as a BO one, because of the lighter weight. While NO only takes about 57% more torque than BO it is amazing that HO will probably take almost three times the torque of BO.

Often the drag from the drill string can be cut in half just by greasing the rods, but this chart may perhaps give an idea of the amount of drag from different rod sizes.

Depth Capacity

Hydracore Drill TypeDepth Capacity
A Core Size 1.062-1.380
Depth Capacity
B Core Size 1.433-1.654
Depth Capacity
N Core Size 1.874-2.248
Depth Capacity
H Core Size 2.500-2.792
Depth Capacity
P Core Size 3.346
Gopher Manportable3,000'1,500'900'500'
Gopher Underground1,600'900'
2000 Manportable3,000'2,000'1,000'
2000 Underground3,000'2,000'1,000'
4000 Manportable5,000'4,000'2,000'1,000'
4000 Underground5000'4,000'2,000'1,000'