Name	DIN338 HSS twist drill bit
Material	HSS 4241, HSS 4341, HSS M2(6542) and M35.
Production technology	roll forged, or half ground(edge ground), or fully ground
Tip degree	118 degree without split point or 135 degree with split point
Surface treatment	black finish, titanium coating, white finish, black and gold and amber finish etc for choose;
DIN338 HSS twist drill bit Size	Inches size from 1/64 to 3/4 by increment 1/64 inches; Metric size from 1.0 to 20mm by increment 0.1mm;
Mark	mark material, size and brand by stamping method or lasering.
Package	5-10PCS per PVC bag or plastic tube or plastic box; or combination set packed in big box such as plastic box or metal box, without or with window.
Brand	GMTOOL, We also accept custom customers' brand (OEM).

● The most common twist drills are made of ordinary high-speed steel(HSS) 4241, produced through rolling, with a hardness of 61-62 HRC. The surface treatment is usually black finish, and their appearance clearly shows a twisted pattern, making them easily identifiable. The tip's degree is 118. They are generally sufficient for daily use, drilling holes in common materials such as wood and low carbon metal, but the number of holes drilled is relatively small, and their lifespan is generally short.

● Medium-quality twist drills are often made from HSS 4341 or 4241 material using a half ground(roll forged first, then edge ground) process. Their hardness is generally around 62-63HRC, making them suitable for beginners in professional DIY projects. The surface treatment is often titanium plating, giving them a noticeable yellow sheen. The head angle is typically 118 degrees, without double back angles, and the shank is a standard round shank.
● Common packaging method is 5-10PCS per plastic tube.

● High-quality twist drills are typically made from M35 material containing 5% cobalt, or from standard M2(6542) material. They are manufactured using a full ground production process, with a clearly visible cutting edge at the start of the flute for easy identification. Common surface treatments include amber finish, white finish, and black & gold finish. The top opening angle is generally 135 degrees, and it features a double cutting edge, called split point. This special design allows for faster chip removal and heat dissipation, thus extending its lifespan and wear resistance.
● The best quality of twist drill bit is made by HSS 5% Cobalt M35 material, which matched with fully ground production process and amber finish.

Comparative of Different Material of HSS for DIN338 HSS Twist Drill Bit

Property	4241	4341	M2	M35
Hardness	HRC 60–62	HRC 61–63	HRC 63–65	HRC 65–67
Wear Resistance	Low	Medium	High	Very High
Hot Hardness	Poor (<300°C)	Moderate (~300°C)	Excellent (~550°C)	Superior (~600°C)
Toughness	High	Medium	Medium-Low	Low
Cost	Lowest	Low	Medium	High

Usage: take out the drill bit which you want size by carefully and install it in drill machine, clamp it tightly by key, then adjust the speed around 550 RPM, Apply pressure uniformly downward.