Also available for demolition purposes are the combo-models that have both rotary hammer and demolition modes. Both hammer drills and rotary hammers are designed to bore at specific optimum drill hole ranges. The most common systems these days, used throughout the industry, were actually designed by Bosch and include: the SDS-Plus and SDX-Max Systems. The chucks in these units are designed to accept special bits for additional strength. If you don’t wish to purchase a rotary hammer for one-time use, they can often be rented. They are, however, a bit pricier and lack the versatility of hammer drills. If you have a number of holes to bore in concrete, these “dedicated” models are the best choice. In fact, applying pressure re-duces the impact. The tool supplies the impact without additional pressure needed from the operator. The impact force is much greater than that of a rotary percussion hammer drill. They have an electro-hammer system with a free-floating percussion piston. Rotary hammers are used for larger chores and are designed primarily for concrete work, although they can be used for softer masonry materials. They’re faster than rotary drills, but slower than the rotary hammers. Hammer drills are primarily designed to be used for masonry work with some light concrete work and they are adequate for most homeowner chores. With the appropriate bit, they can also be used for drilling other materials, such as wood or metal. Most of these drills are also available as combination, rotary drill/drivers and hammer drills with the modes selected by a switch. This is the most common type of hammer drill in use by homeowners. With these types of tools the harder you push, the harder the impact, but also the more wear-and-tear on the unit. Penetration is determined by the rate of the rotary percussion hammer providing impact energy, as well as the pressure applied to the bit and the RPM. This consists of a gear assembly providing an impact to the chuck and these impacts may range from 20,000 to over 50,000 blows per minute (BPM). The drill also has an electro-mechanical hammering system. This type of drill has the same basic three-jaw chuck as a rotary drill. The drilling chore is done much quicker and easier with a rotary percussion hammer drill. Frequently removing the bit from the hole to clear out the cuttings will help prevent the bit from overheating. The drill should be run fairly low, around 350 to 750 RPM.

As the hardness of the material and the size of the hole increases, more pressure is required. In this case the penetration is directly dependent on the amount of pressure applied and the RPM. In the case of just a few holes, they can be bored with an ordinary rotary drill and a masonry bit. Three different types of tools can be used for boring these holes: a rotary drill, a rotary percussion hammer drill and a rotary hammer. The flashing around chimneys is another example. Good examples include porch piers, step railings and safety hand bars.

Alternative Heating & Fireplace InsertsĪnchoring items to concrete or masonry often requires boring a hole, inserting an anchor of some sort, then bolting or screwing the item in place.

Air hammer masonry bits