The dimensions that will be needed is the top head travel which will tell you how long your hammer can be, the inside width of the mast which will tell you how wide your hammer can be and the depth of the mast from the center of the drill rod to the inside back of the mast.
The right amount of top head travel will give you the room you need to fit the size hammer you want into the mast and will give the amount of drill out you require. When you decide on the model of hammer you require you will have to figure out whether or not it will work on the rig you are planning on using and whether it will give you the amount of drill out you need.
An easy way to figure this out is to add the length of the hammer to a length of drill rod. You will need this length just to fit the hammer into the drill string. Any extra is your drill out.
Example: 20 feet for the drill rod, + 5 feet for the hammer = 25 feet. If you have 26 feet of top head travel, you will have 1 foot of drill out, if you have 29 feet of top head travel, you will have4 feet of drill out etc.
The inside width of the mast will need to be wide enough the accommodate mast guides.
Example: hammer width, + guide width = minimum inside mast width. The minimum amount of room that would be needed to fit the hammer into the mast with guides would be the hammer width 1 inch on each side of the hammer. Guides are always made to fit the mast so when the hammer and the rig are known the appropriate guides can be supplied with the hammer.
Rigs come in many shapes and sizes and so there are many options for guides available. Truss style masts can use simple bolt on mast guides or extra rails can be added that will allow the hammer to be hydraulically swung out of the mast so other types of work can be done that doesn’t require the hammer.
Single pole mast can be used with simple bolt on mast guides or a swing out hammer sled can be added which will allow the hammer to be hydraulically swung out to the side for work that doesn’t require the hammer.
When selecting a hammer for certain drilling conditions and pipe sizes, there are no cut in stone method. Different drilling conditions require different amounts of force to hammer pipe into the ground. It can require as much force to drive a small pipe into hard ground as a large pipe into soft ground so ground conditions alone or pipe size alone are not a good method. If your driving your pipe ahead instead of drilling a hole first to drive into, you will require a larger hammer.
A good way to narrow down your choices is to look at what other drillers are using in similar drilling conditions and how successful they are with the size of hammer they are using. If your not sure if a particular size hammer is big enough or is maybe its to big, our hydraulic hammers can have their stroke varied very precisely to lessen their force when you don’t want to hit the pipe as hard. Need more help? Give us a call toll free at 1-866-338-5090