Is a hydraulic impact driver quieter than a standard one?
No, a hydraulic impact driver is not always quieter on its maker's paperwork. Milwaukee's SURGE drivers list far less than its M18 FUEL driver, while DEWALT's hydraulic DCF870 declares more than its own conventional ATOMIC DCF850.
Milwaukee's European pages show the pattern the marketing promises. The M12 SURGE lists 84.07 dB(A) at the operator, the first M18 SURGE 87.9 and the second 94, against 100.27 for the conventional M18 FUEL 2953-20, all on the same kind of page with an uncertainty of 3.
DEWALT's declarations break it. Under EN62841-2-2 the hydraulic DCF870 declares 93 dB(A) at the ear, the conventional DCF850 88 and the older DCF787 92, each with a K of 3. On DEWALT's own figures, its hydraulic driver is no quieter than the ATOMIC under the standard test.
How many decibels is an impact driver?
An impact driver's declared figure at the operator's ear runs from 84.07 dB(A) to 100.27 dB(A) once Makita's soft-grade 80 is set aside, and sound power from 95.07 to 111.27. Those are split below by the standard behind them.
Declarations to EN 62841
These figures name EN 62841-2-2, except Hilti and Festool, which cite the EN 62841 series without the part number. Sound pressure at the ear, lowest first:
- DEWALT DCF850 (conventional): 88 dB(A), K 3
- DEWALT DCF787 (conventional, not a pick): 92 dB(A), K 3
- DEWALT DCF870 (hydraulic): 93 dB(A), K 3
- Hilti SID 4-22 (conventional): 95 dB(A), K 3
- Makita XDT19, sold in Europe as the DTD172 (conventional): 100 dB(A), K 3
- Festool TID 18 (conventional): 100.00 dB(A), K 3
A gap of 3 dB or less sits inside the stated uncertainty, so DEWALT's DCF787 and DCF870 are level, and so are the Makita and the Festool. The DCF850's 5 dB lead over the DCF870 is wider than the K.
Milwaukee's European pages
On each European product page, Milwaukee prints both quantities, each followed by an uncertainty of 3 dB(A),, but names no standard beside them. These four are ranked only against each other:
- M12 FUEL SURGE 2551-20 (M12 FQID): 84.07 dB(A)
- M18 FUEL SURGE 2760-20 (M18 FQID): 87.9 dB(A)
- M18 FUEL SURGE 2761-20 (M18 FIDRQ): 94 dB(A)
- M18 FUEL 2953-20 (M18 FID3): 100.27 dB(A)
None of the documents we read for these ten drivers cites the older EN 60745, so no figure here needed a group of its own on that account.
Which Milwaukee impact driver is the quietest?
The M12 FUEL SURGE 2551-20 is the quietest Milwaukee impact driver on Milwaukee's own European pages, at 84.07 dB(A) for the operator and 95.07 sound power, 16.2 dB below the conventional M18 FUEL 2953-20.
The trade is torque. The M12 SURGE and the first M18 SURGE both give 450 in-lbs on their US pages, while the second M18 SURGE gives 1,000 and the 2953-20 gives 2,000. Milwaukee's figures climb with them: 84.07, 87.9, 94 and 100.27 dB(A).
One oddity on the M12 page: a second block of data lists 84,7 dB Lpa and 95,7 dB Lwa. We quote the 84.07 because it sits in the same table as the uncertainty rows, and we name both in the catalog entry.
Why does DEWALT's quietest impact driver declare more than the ATOMIC?
DEWALT's hydraulic DCF870 carries a 93 dB(A) operator figure and the ATOMIC DCF850 an 88 because each figure comes from the EN62841-2-2 test, while DEWALT's "quietest" claim comes from a deck screw test of its own design.
The US page footnotes "up to 57% quieter" as an RMS sound pressure difference against the DCF787, driving a 3 in. deck screw into a treated 4x4. Its "quietest impact driver" claim compares the DCF870, while impacting only, against DEWALT's current cordless drivers with a 5 in. screw into a 6x6.
DEWALT does not reconcile those claims with its own declarations, which put the DCF787 at 92 dB(A) and the DCF870 at 93 under the standard. The DCF870's manual says its figure "represents the main applications of the tool", while the DCF850's covers fasteners of the tool's maximum capacity.
Both wordings sit under the same EN62841-2-2 test, so we rank the DCF850 lower, and we read DEWALT's percentage as describing a deck screw rather than the standardized load.
How quiet is Makita's oil-impulse driver?
Makita's oil-impulse XST01 declares 80 dB(A) at the operator and 88 dB(A) sound power to EN62841-2-2, but only in its soft impact force grade, so the figure describes the tool at its gentlest setting.
Makita's EU manual for the DTS131 and DTS141 names that grade beside the numbers. The DTS141 is the European twin of the US XST01: both manuals list 3,200, 2,000 and 1,200 RPM and 2,700, 2,200 and 1,400 IPM across the three grades, and a 136 mm length.
Every other driver here is declared driving at full capacity, so the 80 is set beside them, not above them. Makita's conventional XDT19 makes the point, declaring 100 dB(A) with no grade named in the same kind of Makita manual.
Makita New Zealand's manual for the same two tools prints 77 dB(A) at the ear in soft grade, "according to EN62841", with no sound power. We use the EU figure, which names part 2-2 and the DTS141 by model.
How does a hydraulic impact driver cut noise?
A hydraulic impact driver passes each blow through oil rather than steel striking steel. Makita calls the XST01 "a hydraulically operated impact tool using oil viscosity to produce impacts".
Milwaukee says its FLUID-DRIVE powertrain "reduces metal on metal contact within the tool", and DEWALT's US page says the DCF870 has "an advanced hydraulic mechanism".
The oil brings a limit. Makita's EU manual warns against using its oil-pulse driver below -10 °C (14 °F), and says a hot tool may take longer to set screws, because oil viscosity changes with temperature.
Torque is the other limit on these models. The XST01 gives 355 in.lbs., the DCF870 56 Nm and the M12 SURGE 450 in-lbs, against 1,825 in-lbs for the ATOMIC DCF850. Only the second M18 SURGE reaches 1,000.
For heavier fasteners, our impact wrench guide covers the bigger tools tested to the same EN 62841-2-2 part, and the cordless drill guide covers drivers that turn screws without hammering.
Why do US impact driver pages give percentages instead of decibels?
US impact driver pages for these models give percentages because the decibel declarations appear only in European and export documents, and the makers do not say why. Not one American page or owner's manual for them that we read gives a decibel value.
Milwaukee's US pages promise "up to 2X quieter" for the M12 SURGE and "50% quieter" for the second M18 SURGE. DEWALT's DCF870 page says "up to 57% quieter", and Makita's XST01 page says its oil drives the impact mechanism "for lower noise".
RYOBI's US page for the 18V ONE+ QuietStrike pulse driver says "50% less noise than an impact driver", gives no decibel figure, and marks the tool Discontinued, so it has no pick.
