Though intermittent rotary drilling at capacity is possible, it’s always better to opt for the next larger hammer if any drilling series requires larger holes. Like any other tool or machinery, constantly pushing a hammer to its extremes will eventually lead to failure. Investing in the next larger hammer up front will pay off in the long run.
By selecting the hammer designed to drill the holes that are needed, users can guarantee faster and more efficient performance. One critical point to keep in mind when using a hammer for rotary drilling chores is to let the tool do the work; applying too much pressure on these tools can actually decrease performance.
Hole Size Matters
In addition, each hammer incorporates the flexibility to rotary drilling of larger holes as well. Bosch SDS-plus hammers can handle carbide-tipped core bits from 2-1/2" up to 3-1/2", and SDS-max hammers can handle carbide-tipped core bits from three inches up to 6" and thru-hole bits up to 3-1/8". The exact size core and thru-hole bits are dependent on the hammer size.
Though occasional rotary drilling at full capacity is possible, you're always better off opting for the next larger hammer for continuous larger hole drilling. Like any other tool, constantly pushing a hammer to its extremes will eventually lead to failure. Investing in the next larger hammer upfront will pay off in the long run.
It’s also important to select a tool with the right functions. Bosch rotary hammers (SDS-plus) offer three modes of operation: hammer drilling, drilling only and chiseling only. Larger combination hammers typically offer two modes: hammer drilling and chiseling only.
When it comes to hammer carbide bits for rotary drilling, it’s best to think of hammers as a system. With all the improvements in power tools over the past few years, the carbide bits have been rapidly improving as well. From two-head cutters to four-head cutters (full head carbide) to bits that specialize in rebar to “stop bits” that control depth to avoid post tension cables, bits have been redesigned to be more durable for increased cutting speed and to keep pace with the increased impact energy of the hammers. Without these improvements, all that pulverized dust generated by rotary drilling would remain in the hole causing heat buildup on the bit tips and eventual bit failure.