Question 1

Noob question, but why do I need five of these bits? It seems like you could get all the increments with one or two.

Accepted Answer

You don't "need" any of these bits.  Both, my...another family member and I purchased these as the touting of cobalt, titanium, and High Speed Steel bits made us both believe they were a steal of a steel deal.  Boy we couldn't have been more wrong!  These are absolute garbage. AGAIN THESE ARE ABSOLUTE GARBAGE BITS. I've got a free pocket knife from a gas station that drills better.
     Shavings from the first time we used these bits were put in the MassSpec at his showed NO cobalt at all present. For those that don't know a mass spectrometer gives you a breakdown of the molecules and elements present in a sample.  Upon my complaining to the seller, I was told well.... "They're only cobalt colored and aren't intended for use on steel or hard metal alloys." You buy a cobalt %containing bits to handle the higher frictional heats encounters when cutting/drilling tougher steel alloys, stainless, or even just wanting your High Speed Steel bits to last longer.  It's so your bit doesn't take damage and be destroyed or worse yet damage the piece you're drilling (especially when you're using tapping fluid too to lubricate the cutting edges reducing that friction and subsequent damaging heat) and M42 is the highest grade of cobalt bits I have & that I know of / have used. You buy titanium bits from M7 (high molybdenum for toughness) to M35 (HSS with a 5% titanium component) or the king of titanium bits and heat dissipation (HSS with 8% titanium) so your bits won't be damaged to the point they're unable to be used again.  These high end bits you pay for ones made right. There are proper recipies the boundaries mix up molten of all the components from the iron and nickel of base steel, to adding molybdenum for toughness, cobalt for  thermal resilience, titanium coatings to reduce friction, and many many more components in a bakery for steel.  These bits are beyond poorly made and are NOT good moreless decent bits.
So I'll reiterate fro my own and others experience, THESE ARE JUNK AND YOU DONT "NEED" THEM.....well unless you need to drill holes in pure Gallium at ambient temperatures above 30°C.
And just a FYI I have 1/8" M42 aircraft legnth bits that'll drill through a 10" hardened steel block and a 1.0" M42 bit that could just about drill aluminum foil without tearing it.  Size has nothing to do with quality.  Small bits for small sheets and big bits for big sheets is a cop out answer to make the customer think they're the problem in how they're using the bits.  The bits are crap and the Seller sends different answers to different people.  They're garbage bits from cheap garbage metal (I hesitate to even call them true steel)

Question 2

Are these bits titanium or cobalt?  The product description shows both titanium & cobalt.

Accepted Answer

You don't "need" any of these bits. Both, my...another family member and I purchased these as the touting of cobalt, titanium, and High Speed Steel bits made us both believe they were a steal of a steel deal. Boy we couldn't have been more wrong! Destroyed 1st use at slow speed off the speed chart and using tapping fluid to lubricate.   These are absolute garbage. AGAIN THESE ARE ABSOLUTE GARBAGE BITS. I've got a free pocket knife from a gas station that drills better.
Shavings from the first time we used these bits were put in the MassSpec at his showed NO cobalt at all present. For those that don't know a mass spectrometer gives you a breakdown of the molecules and elements present in a sample. Upon my complaining to the seller, I was told well.... "They're only cobalt colored and aren't intended for use on steel or hard metal alloys." You buy a cobalt %containing bits to handle the higher frictional heats encounters when cutting/drilling tougher steel alloys, stainless, or even just wanting your High Speed Steel bits to last longer. It's so your bit doesn't take damage and be destroyed or worse yet damage the piece you're drilling (especially when you're using tapping fluid too to lubricate the cutting edges reducing that friction and subsequent damaging heat) and M42 is the highest grade of cobalt bits I have & that I know of / have used. You buy titanium bits from M7 (high molybdenum for toughness) to M35 (HSS with a 5% titanium component) or the king of titanium bits and heat dissipation (HSS with 8% titanium) so your bits won't be damaged to the point they're unable to be used again. These high end bits you pay for ones made right. There are proper recipies the boundaries mix up molten of all the components from the iron and nickel of base steel, to adding molybdenum for toughness, cobalt for thermal resilience, titanium coatings to reduce friction, and many many more components in a bakery for steel. These bits are beyond poorly made and are NOT good moreless decent bits.
So I'll reiterate fro my own and others experience, THESE ARE JUNK AND YOU DONT "NEED" THEM.....well unless you need to drill holes in pure Gallium at ambient temperatures above 30°C.
And just a FYI I have 1/8" M42 aircraft legnth bits that'll drill through a 10" hardened steel block and a 1.0" M42 bit that could just about drill aluminum foil without tearing it. Size has nothing to do with quality. Small bits for small sheets and big bits for big sheets is a cop out answer to make the customer think they're the problem in how they're using the bits. The bits are crap and the Seller sends different answers to different people. They're garbage bits from cheap garbage metal (I hesitate to even call them true steel) see less

Question 3

How good is the quality?

Accepted Answer

You don't "need" any of these bits. Both, my...another family member and I purchased these as the touting of cobalt, titanium, and High Speed Steel bits made us both believe they were a steal of a steel deal. Boy we couldn't have been more wrong!  They were destroyed the first time used.  Following the slow speed on the charts for the 2 steels and using tapping fluid to lubricate.  These are absolute garbage. AGAIN THESE ARE ABSOLUTE GARBAGE BITS. I've got a free pocket knife from a gas station that drills better.
Shavings from the first time we used these bits were put in the MassSpec at his showed NO cobalt at all present. For those that don't know a mass spectrometer gives you a breakdown of the molecules and elements present in a sample. Upon my complaining to the seller, I was told well.... "They're only cobalt colored and aren't intended for use on steel or hard metal alloys." You buy a cobalt %containing bits to handle the higher frictional heats encounters when cutting/drilling tougher steel alloys, stainless, or even just wanting your High Speed Steel bits to last longer. It's so your bit doesn't take damage and be destroyed or worse yet damage the piece you're drilling (especially when you're using tapping fluid too to lubricate the cutting edges reducing that friction and subsequent damaging heat) and M42 is the highest grade of cobalt bits I have & that I know of / have used. You buy titanium bits from M7 (high molybdenum for toughness) to M35 (HSS with a 5% titanium component) or the king of titanium bits and heat dissipation (HSS with 8% titanium) so your bits won't be damaged to the point they're unable to be used again. These high end bits you pay for ones made right. There are proper recipies the boundaries mix up molten of all the components from the iron and nickel of base steel, to adding molybdenum for toughness, cobalt for thermal resilience, titanium coatings to reduce friction, and many many more components in a bakery for steel. These bits are beyond poorly made and are NOT good moreless decent bits.
So I'll reiterate fro my own and others experience, THESE ARE JUNK AND YOU DONT "NEED" THEM.....well unless you need to drill holes in pure Gallium at ambient temperatures above 30°C.
And just a FYI I have 1/8" M42 aircraft legnth bits that'll drill through a 10" hardened steel block and a 1.0" M42 bit that could just about drill aluminum foil without tearing it. Size has nothing to do with quality. Small bits for small sheets and big bits for big sheets is a cop out answer to make the customer think they're the problem in how they're using the bits. The bits are crap and the Seller sends different answers to different people. They're garbage bits from cheap garbage metal (I hesitate to even call them true steel) see less

Question 4

Would this work on hardened steel?

Accepted Answer

You don't "need" any of these bits. Both, my...another family member and I purchased these as the touting of cobalt, titanium, and High Speed Steel bits made us both believe they were a steal of a steel deal. Boy we couldn't have been more wrong!  They were destroyed the first time we used them; at slow speed following the reccomend speed charts for the metal with a cobalt bit, and using tapping fluid to lubricate the whole time.  I returned my set and wish we hadn't thrown out the messed up ones.  We had to buy all new material with the damage these bits did not cutting correctly coming off center and edges disentigrating.  These are absolute garbage. AGAIN THESE ARE ABSOLUTE GARBAGE BITS. I've got a free pocket knife from a gas station that drills better.
Shavings from the first time we used these bits were put in the MassSpec at his showed NO cobalt at all present. For those that don't know a mass spectrometer gives you a breakdown of the molecules and elements present in a sample. Upon my complaining to the seller, I was told well.... "They're only cobalt colored and aren't intended for use on steel or hard metal alloys." You buy a cobalt %containing bits to handle the higher frictional heats encounters when cutting/drilling tougher steel alloys, stainless, or even just wanting your High Speed Steel bits to last longer. It's so your bit doesn't take damage and be destroyed or worse yet damage the piece you're drilling (especially when you're using tapping fluid too to lubricate the cutting edges reducing that friction and subsequent damaging heat) and M42 is the highest grade of cobalt bits I have & that I know of / have used. You buy titanium bits from M7 (high molybdenum for toughness) to M35 (HSS with a 5% titanium component) or the king of titanium bits and heat dissipation (HSS with 8% titanium) so your bits won't be damaged to the point they're unable to be used again. These high end bits you pay for ones made right. There are proper recipies the boundaries mix up molten of all the components from the iron and nickel of base steel, to adding molybdenum for toughness, cobalt for thermal resilience, titanium coatings to reduce friction, and many many more components in a bakery for steel. These bits are beyond poorly made and are NOT good moreless decent bits.
So I'll reiterate fro my own and others experience, THESE ARE JUNK AND YOU DONT "NEED" THEM.....well unless you need to drill holes in pure Gallium at ambient temperatures above 30°C.
And just a FYI I have 1/8" M42 aircraft legnth bits that'll drill through a 10" hardened steel block and a 1.0" M42 bit that could just about drill aluminum foil without tearing it. Size has nothing to do with quality. Small bits for small sheets and big bits for big sheets is a cop out answer to make the customer think they're the problem in how they're using the bits. The bits are crap and the Seller sends different answers to different people. They're garbage bits from cheap garbage metal (I hesitate to even call them true steel) see less

ASIN	B0177PN6SI
Best Sellers Rank	#5,486 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #12 in Step Drill Bits
Brand Name	ZELCAN
Customer Reviews	4.4 4.4 out of 5 stars (10,673)
Cutting Angle String	135 degrees
Cutting Diameter	0.38 inches
Finish Types	Aluminum, Smooth, Steel, Titanium
Global Trade Identification Number	00640674583197
Item Dimensions	4.33 x 1.57 x 6.1 inches
Item Highlight	5PCS 50 Sizes with Aluminum Case
Item Weight	575 g
Manufacturer	ZELCAN
Minimum Bore Diameter	0.25 inches
Model	SDB-2021-05-YKFBA-1
Number of Flutes	2
Number of Pieces	5
Part Number	CO-Z SDB-0000
Point Style	Step Point
Set Name	5 PC Set
Shank Type	Straight
Surface Recommendation	Aluminum
Tool Flute Type	Spiral
UPC	640674583197
Unit Count	1 Count

5PCS Titanium Step Drill Bit Set, 50 Sizes with Aluminum Case

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