Drilling Metal

15 Frequently asked questions

Q) What are cobalt drill bits?

A) Cobalt drill bits are drill bits comprising of different metals including a percentage of cobalt. The two most common cobalt percentages are

5% (M35)

8% (M42)

Q) When to use cobalt drill bits?

A) Cobalt drill bits should be used for drilling metal. They are particularly well suited to drilling harder metals such as stainless steel. This is due to the fact that the addition of cobalt enables the drill bit to perform at higher temperatures and also helps to reduce heat build up.

Q) What is the difference between M35 and M42 cobalt drill bits?

A) Cobalt drill bits are drill bits comprising of different metals including a percentage of cobalt.

M35 cobalt drill bits contain approximately 5% cobalt plus a mixture of other metals

M42 cobalt drill bits contain approximately 8% cobalt plus a mixture of other metals

Q) M35 V's M42 cobalt drill bits? Which should I buy?

A) An increasing % of cobalt has two main effects on a drill bit :-

  1. It enables the drill bit to drill harder metals
  2. It increases the brittleness of the drill bit

An M35 (5% cobalt) drill bit will drill the majority of metals most people will need to drill. The added advantage of M35 cobalt drill bits is that they can be used in a hand held drill without too much fear of breakage.

An M42 (8% cobalt) drill bit will drill harder metals however will also be more prone to breakage due to its inceased brittleness. M42 cobalt drill bits are best suited to use in a pedestal drill where direction of drilling is controlled better than a hand drill.

Q) Is it possible to resharpen cobalt drill bits?

A) Cobalt drill bits can be resharpened. They can be resharpened using a drill bit sharpener or if you are skilled you can use a grinding disc and resharper by hand.

Q) How long will a Cobalt drill bit last?

A) Unfortunately there are too many variables at play in drilling metal to accurately say how long any type of drill bit will last. These variable factors include :

  • Speed of drilling
  • How much pressure is used in drilling
  • Use of lubricant when drilling
  • Force of initial impact between drill bit and metal being drilled
  • Time between ‘rest’ periods during drilling 

Clearly a drill bit which is used with respect, at the correct speed and lubricated regularly will last longer than one which is not.

Read customer reviews for feedback on results for TTP HARD cobalt drill bits

Q) Why TTP HARD cobalt drill bits?

A) TTP HARD cobalt drill bits are M35 cobalt drill bits. This means that they contain approximately 5% cobalt. This will allow the drills to drill the majority of hard metals including stainless steel.

The remaining 95% is made up of a mixture of other metals including molybdenum which greatly increases the drill bits ability to withstand higher temperatures.

Because TTP HARD drills have 5% cobalt throughout the drill bit (not coated) it can be resharpened.

The majority* of TTP HARD drill bits have a 135 deg split point which means they will start drilling/cutting immediately. The 135 deg split point also greatly reduces the chance of the drill bit ‘walking’ or sliding. 

* Only the 4 smallest diameter drill bits do not have 135 degree split point. They instaed have 118 degree point, this is due to the difficulty of creating a 135 degree point on such a small diameter drill bit.  

See complete drill bit dimensions size charts here :

Imperial drill bit range dimensions size chart

Metric drill bit range dimensions size chart

Q) Have TTP HARD cobalt drill bits been tested for hardness?

A) Yes, TTP HARD cobalt drill bits were tested for hardness by the international testing house SGS Testing. A Rockwell C Harndess Rating of 66 was You can view the certified of hardness here.

You can watch the video of the hardness testing procedure here

Q) Do TTP HARD cobalt drill bits come with a guarantee?

A) TTP HARD Cobalt drill bits come with a 3 month money back guarantee.

If within 3 months of purchase you are not satisfied with the performance of our drill bits you can return them and we will refund your purcahse price in full.

Q) Has 'CUT-IT' metal cutting paste been tested?

A) Yes TTP CUT-IT metal cutting paste was tested by Subsea Fluid Services in accordance with ASTM D 3233-93 which is the Standard Test Methods for Measurement of Extreme Pressure Properties of Fluid Lubricants (Falex Pin and Vee Block Methods).

The lubricant properties of CUT-IT metal cutting paste was tested under 1300lbs of pressure for 30 minutes. The result was that CUT-IT lubricated well under theses conditions.

Read test report

Q) When should I use a metal cutting lubricant?

A) A metal cutting lubricant should be used when you are cutting or drilling any metal. Its purpose is to reduce friction which will make the cutting or drilling job easier and also reduce heat build up. Both these actions will result in inceasing the life of your drill bit or cutting tool.

Q) Cutting oil v's Cutting paste?

A) This often comes down to personal preference. Many will argue that a paste is more efficient as there is no wastage as is sometimes associated with spraying an oil.

If you are drilling overhead a paste will adhere to your drill bit and lubricate where an oil would run off.

If you are serious about protecting your drill bits it may be worth investing in a cutting paste or oil which contains quality high pressure additives and has a proven track record.

Q) Where can I buy TTP HARD cobalt drill bits ?

A) USA and Canadian customers can buy TTP HARD cobalt drill bits  either on www.ttp-hard-drills.net  or on Amazon USA.

Customers from the rest of the world can buy from www.ttp-hard-drills.com


Q) What advice can you give someone drilling metal ?

A) We would advise you firstly determine the metal you intend to drill which will in turn determine the type of drill bit you require. Cobalt drill bits are the best choice for the majority of metals people need to drill. After determining the drill bit type you should :-

  • Buy a good quality drill bit
  • Use appropriate safety protection
  • Drill at a suitable speed (if in doubt it is best to drill slowly) * See links to speed and feed sheets below
  • Use a metal drilling lubricant
  • Avoid using excessive pressure (allow the drill bit to do the work)
  • Take breaks to avoid the drill bit overheating

* Imperial sized cobalt drill bit speed and feed sheet

* Metric sized cobalt drill bit speed and feed sheet

Q) What type of drill bit for different metal types ?

A) There are many types of drill bits available for drilling different metal types. These include HSS, Titanium, Carbide, Cobalt and Tungston.

They vary not only in what they can drill but can also vary greatly in price, hardness and suitability for either use in a hand drill or a pedestal drill.

Your choice of drill bit therefore may not purely be decided on based on the type of metal you wish to drill but also 

  • How often you will drill that metal
  • How much you are willing to spend
  • Wheather you are drilling with a hand drill or a pedestal drill

For the majority of individuals cobalt drill bits will drill through most metals they will need to drill including stainless steel, hardened steel and high tensile bolts.  Read testimonials from TTP HARD cobalt drill bit customers to see what they have drilled.

Wayne Winton of Tri-County Locksmiths wrote an excellent piece for  Safe & Vault Technology entitled ‘The Ultimate Guide to Drill Bits‘ in which he highlights the capabilities of different types of metal drill bits.

Icon for Buy imperial TTP HARD metal drill bits  Icon for Buy metric TTP HARD metal drill bits                                   icon for customer reviews of TTP HARD metal cobalt drill bits  Drilling metal video icon  icon certificate of hardness for TTP HARD drills