Hammer Drill Size and Installation Time
Drill size has a measurable impact on asphalt anchor installation time. In our comparison, a Bosch RH745 drilled the same 1.5” hole in 1:45 that took a BAUER 11 Amp SDS-MAX rotary hammer 2:30.
That is a 45-second savings per large hole, or about a 30% reduction in drilling time. The difference matters most when the job has many anchors, larger-diameter holes, or deeper drilling. For a single small installation, the tool upgrade may not justify itself. For contractor or repeat work, faster drilling can reduce labor cost and make the job more predictable.
Why Drill Size Matters
Section titled “Why Drill Size Matters”Asphalt anchor installation requires drilling an oversize hole to the correct depth and diameter. The drill has to remove material consistently without binding, overheating, or wearing out the operator.
A larger rotary hammer can help because it usually provides:
- More impact energy
- Better speed under load
- Better heat management
- Less operator fatigue
- Better performance with larger bits
- Faster recovery when flutes load with asphalt and aggregate
The drill does not replace the installation procedure. Hole diameter, depth, cleaning, adhesive placement, and anchor insertion still need to follow the standard installation guide.
The Comparison
Section titled “The Comparison”The measured 1.5” hole comparison was:
| Rotary hammer | Approximate cost | Hole diameter | Time per hole |
|---|---|---|---|
| BAUER 11 Amp, 1-9/16 in. SDS-MAX Type Variable-Speed Rotary Hammer | $150 | 1.5” | 2:30 |
| Bosch RH745 SDS-max 1-3/4 In. Rotary Hammer | $830 | 1.5” | 1:45 |
The same drill bit was used for both tools. In this test, the Bosch reduced drilling time by 45 seconds per hole. Put another way, the BAUER took about 43% longer, and the Bosch could drill about 43% more 1.5” holes in the same active drilling time.
Video Comparison
Section titled “Video Comparison”Smaller Hole Timing
Section titled “Smaller Hole Timing”For smaller holes, drilling time is roughly proportional to the area of the hole, assuming the same asphalt, bit condition, and drill class.
In testing with the Bosch RH745:
| Hole diameter | Product | Time per hole |
|---|---|---|
| 7/8” | SP10 | 0:15 |
| 1-1/8” | SP18 | 0:30 |
| 1.5” | SP58 | 1:45 |
These times are useful for planning, but they are not universal. Asphalt strength, aggregate size, aggregate type, pavement age, moisture, temperature, and the base under the asphalt can all change drilling speed.
For planning purposes, allow for significant variance. We have seen difficult asphalt conditions increase drilling time by up to 100%.
Drill Bit Comparison
Section titled “Drill Bit Comparison”We also compared a roughly $200 Milwaukee drill bit against the bit we sell. There was no meaningful time difference in the holes tested.
The Milwaukee bit did feel smoother and bound up less often. That can still matter on a full job, because binding affects operator fatigue, rhythm, and the chance of losing time clearing the bit.
The practical conclusion is:
- A more expensive bit may not drill faster in seconds per hole.
- A smoother bit can still make the job easier.
- Bit condition and flute clearing still matter.
- Use the correct diameter and shank type for the anchor and drill.
When the Faster Drill Pays Off
Section titled “When the Faster Drill Pays Off”A more expensive drill is easier to justify when:
- The job includes dozens or hundreds of anchors
- The anchor model requires a larger or deeper hole
- Labor is the largest cost in the job
- The crew installs anchors regularly
- The site has hard aggregate or thicker asphalt
- The same drill will be used across multiple jobs
For occasional small jobs, a lower-cost drill may be acceptable if it can hold the correct bit, drill to the required depth, and survive the workload.
Bit Size Still Matters
Section titled “Bit Size Still Matters”The drill is only part of the system. A premium rotary hammer with the wrong or worn bit will still perform poorly.
Confirm:
- The bit diameter matches the anchor model
- The bit is long enough for the required depth
- The bit shank matches the drill, such as SDS+ or SDS MAX
- The bit cuts cleanly and clears material through the flutes
- The operator clears the flutes before they pack with debris
See the anchor specifications table for required drill diameter and depth by anchor model.
Impact on Total Installation Time
Section titled “Impact on Total Installation Time”Drilling faster does not reduce every part of the job. The crew still needs to mark locations, clean holes, place adhesive, insert anchors, clean excess adhesive, and wait for cure before loading.
That means the total job savings depend on how much of the job is drilling. If drilling is half of the active labor time, reducing drilling time by 30% does not make the whole job 30% faster. It still may be meaningful, especially on larger projects.
For the broader planning view, see How Long Does Asphalt Anchor Installation Take?.
Practical Recommendation
Section titled “Practical Recommendation”Use the largest practical rotary hammer for the hole size, job size, and crew. For repeat installation work, a better drill can pay for itself through faster holes, less fatigue, and fewer delays.
For small one-off jobs, the priority is not brand or price. The priority is whether the drill and bit can produce the correct hole cleanly and reliably.