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High temperature and friction

  1. Oct 25, 2016 #1
    if i heat up my drill bit before drilling, will that result in less coefficient of friction between the drill bit and wood material or metal material?
    and if so yes will it give me more time before the drill bit wears out because of high temperature as it will be harder to reach high temperature that will damage the bit or will it just wear out really quickly?
     
  2. jcsd
  3. Oct 25, 2016 #2

    DrClaude

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    Staff: Mentor

    This is really not my field of expertise, so I hope that someone else will chime in, but I would think that heating up the drill bit will hasten the wear.

    Also, by experience, drill bits heat up quite quickly when you use them, so pre-heating them would not change much.
     
  4. Oct 25, 2016 #3

    JBA

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    The short answer to your question is that heat from and while drilling is bad. For a longer answer to your question see the below.

    High temperatures are to be avoided when drilling because the drill point fluke sharp cutting edges are where the most friction and heating occurs and on hardened metal alloy drills these thin edges can easily be heated to a temperature at which they begin to lose hardness and become worn and damaged.

    With any cutting tool, it is necessary to either cut slowly enough to allow heat transfer away from the cutting edges to the base and cut materials and, in the case of drills, up the shaft to cool the cutting edges. For wood this also means reducing drilling speed to heat charring of the wood. For metals, it is best to also use a lubricant.to minimize the cutting edge friction and carry heat away from the drill tip cutting edges.

    When drilling plastics, and low melting temperature metals like aluminum, excessive drill heating must be avoided because excess heat will result in melting of the drilled material, which then hardens in the drill"s spirals so that cut material cannot be removed from the hole.

    When cutting nickel alloy metals like stainless steels, particularly 316 SST, using only very sharp drills and lubrication is particularly important because higher drill loads are required to insure that the drill tip edges cut without slipping on the SST material surface because slippage will result in surface hardening of the material which then requires added pressure to resume material cutting which increases friction heating that then results in wear and damage to the drills cutting edges. With hardened metal alloy drills the friction from trying to restart the drilling can damage the cutting edges enough to prevent resuming cutting of the material with that drill.
     
  5. Oct 26, 2016 #4
    thank you for the thorough info
     
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