What RPM should I use for drilling steel?

For mild steel with HSS drill bits, use approximately 25 m/min surface speed. For a 10mm bit, that is about 800 RPM. Stainless steel requires slower speeds — roughly 15 m/min, or about 480 RPM for a 10mm bit. Always use cutting fluid and reduce speed for deeper holes.

Should I drill concrete at high speed?

No. Concrete drilling with an SDS rotary hammer uses relatively low RPM (typically 600–1200 RPM) combined with high-frequency hammer impacts. The hammer action does most of the work. Running too fast generates excess heat and wears the carbide tip prematurely.

What happens if I drill too fast?

Excessive RPM causes overheating, which softens HSS cutting edges and accelerates wear. In metals, it leads to work hardening (especially in stainless steel). In wood, it can cause burning. In masonry, it glazes the carbide tip. Always match RPM to material and diameter.

Do I need to reduce speed for larger drill bits?

Yes. RPM is inversely proportional to diameter. A 20mm bit should run at half the RPM of a 10mm bit in the same material. This keeps the cutting edge at the correct surface speed. Larger bits also require more torque and lower feed pressure.

Drill Bit RPM Chart by Material & Diameter

Key Specification / Takeaways

01. Professional technical insights and practical recommendations
02. Best practices based on real engineering experience
03. In-depth analysis of materials science and manufacturing processes

HSS Drill Bit Speed Chart

The table below shows recommended RPM for standard HSS (High-Speed Steel) drill bits. Values are calculated using the formula RPM = (Surface Speed × 1000) / (π × Diameter) with standard cutting speeds: Mild Steel 25 m/min, Stainless Steel 15 m/min, Aluminum 75 m/min, Cast Iron 20 m/min.

Bit Diameter	Mild Steel (RPM)	Stainless Steel (RPM)	Aluminum (RPM)	Cast Iron (RPM)
1 mm	7,960	4,775	23,875	6,365
2 mm	3,980	2,390	11,940	3,185
3 mm	2,650	1,590	7,960	2,120
4 mm	1,990	1,195	5,970	1,590
5 mm	1,590	955	4,775	1,275
6 mm	1,325	795	3,980	1,060
8 mm	995	595	2,985	795
10 mm	795	480	2,390	635
12 mm	665	400	1,990	530
16 mm	500	300	1,490	400
20 mm	400	240	1,195	320
25 mm	320	190	955	255

Tip: Use cutting oil or coolant for all metal drilling. Reduce RPM by 20–30% for deep holes (depth > 3× diameter).

Carbide Tipped Drill Bit Speed Chart

Carbide-tipped and solid carbide drill bits can operate at significantly higher surface speeds than HSS. Typical cutting speeds: Mild Steel 60 m/min, Stainless Steel 35 m/min, Aluminum 150 m/min, Cast Iron 50 m/min.

Bit Diameter	Mild Steel (RPM)	Stainless Steel (RPM)	Aluminum (RPM)	Cast Iron (RPM)
1 mm	19,100	11,140	47,750	15,915
2 mm	9,550	5,570	23,875	7,960
3 mm	6,365	3,715	15,915	5,305
4 mm	4,775	2,785	11,940	3,980
5 mm	3,820	2,230	9,550	3,185
6 mm	3,185	1,855	7,960	2,650
8 mm	2,390	1,390	5,970	1,990
10 mm	1,910	1,115	4,775	1,590
12 mm	1,590	930	3,980	1,325
16 mm	1,195	695	2,985	995
20 mm	955	555	2,390	795
25 mm	765	445	1,910	635

Note: Solid carbide bits achieve higher speeds than carbide-tipped bits. Use through-tool coolant when available. Rigid machine setup is essential for carbide tooling.

Masonry & Concrete Drill Bit Speed Chart

Masonry bits (SDS-Plus and SDS-Max) are used with rotary hammers. The RPM is lower than metal drilling because the hammer mechanism provides the primary cutting force. These values represent typical rotary hammer settings.

Bit Diameter	Shank Type	Concrete (RPM)	Brick (RPM)	Block (RPM)
5 mm	SDS-Plus	1,100	1,400	1,500
6 mm	SDS-Plus	1,000	1,300	1,400
8 mm	SDS-Plus	900	1,100	1,200
10 mm	SDS-Plus	800	1,000	1,100
12 mm	SDS-Plus	700	900	1,000
14 mm	SDS-Plus	600	800	900
16 mm	SDS-Plus	550	700	800
20 mm	SDS-Plus	450	600	700
22 mm	SDS-Max	400	500	600
25 mm	SDS-Max	350	450	550
28 mm	SDS-Max	300	400	500
32 mm	SDS-Max	250	350	450

Important: Always use hammer mode (rotary + impact) for concrete. Brick and block can sometimes be drilled in rotation-only mode with light pressure. Never force the bit — let the hammer do the work.

Wood Drill Bit Speed Chart

Wood drilling generally allows higher RPMs than metal. However, larger bits — especially large wood-boring bits and hole cutters — must run slower to prevent burning and maintain control.

Bit Diameter	Bit Type	Softwood (RPM)	Hardwood (RPM)
3 mm	Twist / Brad Point	3,500	2,500
5 mm	Twist / Brad Point	3,000	2,000
8 mm	Twist / Brad Point	2,500	1,500
10 mm	Twist / Brad Point	2,000	1,200
12 mm	Brad Point / Spade	1,800	1,000
16 mm	Large wood bit	1,500	800
20 mm	Large wood bit	1,200	700
25 mm	Large wood bit	1,000	600
30 mm	Large wood bit / Hole cutter	800	500
35 mm	Large wood bit / Hole cutter	700	400
40 mm	Hole Saw	600	350
50 mm	Hole Saw	450	250

Tip: Back off the pressure periodically to clear chips, especially with large wood-boring bits. Use a sacrificial board underneath to prevent blowout.

How to Calculate Drill Speed

The universal formula for calculating drill bit RPM is:

RPM = (Cutting Speed × 1000) / (π × Diameter)

Where:

Cutting Speed = surface speed in meters per minute (m/min)
Diameter = drill bit diameter in millimeters (mm)
π = 3.14159

Common Cutting Speeds by Material (HSS Bits)

Material	Cutting Speed (m/min)
Mild Steel / Carbon Steel	25–30
Stainless Steel	12–18
Aluminum	60–90
Cast Iron	18–25
Brass / Bronze	30–50
Copper	25–40
Titanium	10–15
Tool Steel (Hardened)	8–12

Adjustment Tips

With coolant/cutting fluid: You can increase RPM by 10–20% compared to dry drilling.
Deep holes (depth > 3× diameter): Reduce RPM by 20–30% and use peck drilling to clear chips.
Pilot holes: Use standard RPM. The pilot hole reduces load on the larger bit.
Cobalt (M35/M42) bits: Can run 10–15% faster than standard HSS in tough alloys.
Coated bits (TiN, TiAlN): Coatings allow 15–30% higher speeds due to reduced friction and heat resistance.

Full RPM Matrix: Diameter × Material

Use this table as a quick-reference when setting drill press speed or adjusting a variable-speed hand drill. Values are for standard HSS bits with cutting fluid where noted. For cobalt (M35/M42) bits, add 10–15%. For TiN-coated bits, add 20–25%.

Bit Ø (mm)	Soft Steel	Stainless 304	Aluminium	Cast Iron	Hardwood	Brick/Masonry
3	2500	1200	4500	2000	3000	600
4	1900	900	3500	1500	2400	500
5	1500	700	2800	1200	1900	450
6	1250	600	2300	1000	1600	400
8	950	450	1800	750	1200	350
10	750	350	1400	600	950	300
12	630	300	1200	500	800	250
16	470	220	900	380	600	200
20	380	180	700	300	480	180
25	300	140	560	240	380	150

All values in RPM. Masonry column applies to SDS-Plus carbide-tipped bits in hammer drill mode.

Speed Multiplier by Bit Coating

Coating	Speed vs Bare HSS	Best Material Gain	Not Suitable For
None (bare HSS)	1.0× (baseline)	—	—
TiN (gold)	+20–25%	Soft steel, wood	Stainless, titanium
TiCN (grey)	+30–40%	Stainless, hard alloys	Aluminium (built-up edge)
TiAlN (dark grey/violet)	+40–60%	Cast iron, dry machining	Aluminium, copper
Black oxide	+5–10%	Steel, iron	Stainless, non-ferrous

Related Procurement Programs

If you are sourcing this product line for a distributor, importer, or private-label channel, these OEM and wholesale programs cover the procurement questions buyers usually ask next.

Metal & Concrete Drilling Tools Distributor Program — A practical OEM supply program for distributors who need both metal drilling and concrete drilling tools: SDS bits, HSS twist drills, M35 cobalt, step drills…
Private Label Drilling Tool Set Matrix for Distributors — A private-label set matrix for distributors and tool brands: SDS sets, HSS drill sets, cobalt upgrades, step drill kits, hole saw kits, mixed installer kits…

Drill Bit Speed Chart: Recommended RPM by Material & Diameter