Question for machine shops: drill bits

cody45

March 12, 2012 12:23

I am confused as to which is the best drill bits to invest in. Cobalt or Titanium??? Im going to get a new 29pc set an definitely going USA manuf. Any advice will be appreciated. Also what is meant by "jobbers legnth"??? thanx in advance

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  p3skyking

  March 12, 2012 13:24

  Both are good, but I personally perfer cobalt for hard to drill metals.

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  azpowerwagon

  March 12, 2012 13:26

  "jobbers length" is a shorter length drill bit than the standard size. Less flex.

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  Mobuck

  March 12, 2012 15:30

  I was drilling some holes in pipe last week and the cobalt bits outlasted titanium by an overwhelming margin. I can't say if the two types were of the same quality since I didn't buy them. The cobalt bits lasted over 50 holes while some of the titanium barely made 5.

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  beantownshootah

  March 13, 2012 15:10

  Cobalt is the best for drilling holes in metal.
  
  Carbide is good for concrete and such.
  
  I think both are probably better than titanium.

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  Riomouse911

  March 13, 2012 16:04

  The "titanium bits" I have seen are High Speed Steel bits coated with titanium nitride...which has a surface that is a lot harder than HSS bits, but wears off when used a lot or sharpened. They're good for steel, but not the best IMO.
  
  Cobalt bits are made of steel blended with Cobalt, which can be sharpened and used again without losing the "Cobalt bit" hardness. They're specifically made for abrasive drilling materials like cast iron.
  
  For my $$, I like the cobalt bits.

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  XXCross

  March 13, 2012 17:21

  The element "cobalt" is in the drill steel itself, "titanium nitride" is strictly a coating on the outer surface of the drill. Titanium works very well in stainless steels and certain other alloys. For general work the cobalt drill would be your best choice.

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  SP45

  March 13, 2012 18:09

  I had to order a drill for drilling mauser actions for scopes some of which are very hard. I called MSC and asked them and they recommended the cobalt. I figulre they deal in this stuff every day so I took their advise.

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  v35

  March 13, 2012 20:43

  Cobalt

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  Dokey

  March 14, 2012 07:27

  If you can afford them carbide is best, especially when drilling hardened metals

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  yonson

  March 17, 2012 17:29

  "Jobber length" is an old term for the most common length sold at retail. Depending on the manufacturer and drill diameter, flute length is generally 8-10 times the drill diameter. The other most common types are taper length (Morse taper shank) and screw machine length (the short drills used in automatic screw machines, generally left handed twist IIRC). There are numerous other types also but these are the most common. This info is from my old copy of Machinery's Handbook.

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