Pneumatic Rock Drills

Rock Drills / Sinker Drills / Demolition Hammers
When you are determining the right tool for the job you need to ask yourself a few simple questions. What is the material you are working with? What kind of time frame are you looking to do the job in?  How often do you plan on using the tool? All of these questions are very helpful. This Guide is not to be considered to be the "bible" and is only meant to be in a generally speaking format. There are plenty of exceptions to the rule but this guide should help you in determining which kind of tool you should be using for your specific job.

Generally speaking all rock drills and jack hammers are considered to be a certain weight class tool. The weight class of a hammer is like determining the size of the hammer. As far as hand-held pneumatic hammers and drills go, the weight classes are typically as follows: Jack Hammers: 80-90 lb, 60 lb, and 35-40 lb. Rock drills: 9 lb, 15 lb, 30 lb, 40 lb, 50 lb, and 60 lb.

Note: 90 80 60 40 30 class is only a general tool weight term it does not represent the actual weight of the tool. The same goes for rockdrills.

80-90 lb class rock drills are generally used with feed legs in mines, blasting in caves, commercial building foundations, and industrial complexes where large construction equipment cannot get into or reach. Concrete or rock is generally 6” thick or more. This class tool generally takes 7/8" Hex X 4 1/4 drill steel. These drills are generally used for deep depths exceeding 15 feet.

50 and 60 lb class rock drills are generally used in the construction industry to drill rock ledges, and mass amounts of holes or T posts and blasting as well. These types of drills are mainly used downward and for vertical use instead of walls and horziontal use due to their weight. This class tool generally takes 1” Hex X 4 1/4 or 7/8” Hex X 3 1/4 drill steel and have the capabilities of drilling 10 to 13 feet deep. They are also good for fast work if you can keep up with the weight and handling of the drill when doing many many holes.

 

35-40 lb class rock drills are used for sidewalks, streets, and some highway use but mostly where concrete is somewhat 4 to 6” thick and drilling depths dont exceed 4 feet. This class tool is also used for breaking up some basements in the Midwest and they are also good for an occasional horizontal hole if assisted by a second man. They can be used to get in between rebar and other tight areas.  This class tool generally takes two size bits, 7/8” Hex X 3 ¼ or 1” Hex X 4 ¼ bits. (some tools will take 7/8” Hex X 4 ¼ bits but seem to be rare)

9-15 lb class rock drills are typically used for overhead drilling and underwater drilling and will occasionally use drill steel that is 7/8 Hex X 3 1/4 or what we call Speed Steel. Speed Steel is not threaded to host a drill bit. It is all one piece and the bit is molded onto the end and not interchangeable. The lengths of Speed Steel come with drilling depths of 8",12" 18" and occasionally in 24".

 

Bit Sizes for Rock Drills

While there are many different sizes and shapes to bits the "cross type" bit seems to be most popular although there are also "button style" bits in the larger diameters.

Drill bit diameters for hand held rock drills range is diameters of 15/16" to 4" diameter. Depending on the diameter of the bit you need the thread of the bit may vary in size as well. Generally speaking, bits with small dimeters have a smaller thread. Threads on bits are not sized with numbers but rather letters. E, H, D, which are most common and Rope thread being used for bit dimaters larger than 4".

Typically drill bits with dimeters of 15/16", 1" , 1 1/8", 1 1/4" use drill steel with E threads.

Typically drill bits with dimeters of 1 3/8", 1 1/2", 1 5/8", 1 3/4", 1 7/8", 2" ,2 1/4",2 1/2", 2 5/8" use drill steel with H threads.

Typically drill bits with dimeters of 1 3/4", 1 7/8", 2" ,2 1/4",2 1/2", 2 5/8", 2 3/4", 3" ,3 1/4", 3 1/2", 4", use drill steel with D threads.

Typically drill bits with dimeters larger than 4" use drill steel with Rope threads. Rope thread sizes generally start at 1" and can be

1 1/4" or 1 1/2" rope as well.

Drill Steel sizes for Rock Drills

Drill steel that we carry range in lengths from 1 Foot, 1 1/2 Foot, 2 Foot, 2 1/2 Foot, 3 Foot, 4, 5, 6, 8, and 10 Foot lengths.

Rock Drills

Jay 734-341-7272