When drilling metal, should I start with a smaller bit before using a larger bit

drillmetal

From this site, it mentions

In other words, most professionals will start with smaller metal drill bits and work up using metal drill bits of various sizes until the hole is the desired diameter.

Is it necessary to start with the smaller metal drill bits? Are there scenarios whereby it is not recommended to start with the smaller drill bits?

Best Answer

Is it necessary to start with smaller metal drill bits? Sometimes

It all depends on the types of metal involved. It also depends on how much you are willing to cool the point of contact.

I have worked extensively with metal over the years. Here's what I do when working with an alloy metal with an unknown composition:

  1. Start with a smaller drill bit, but not so thin that it will quickly bend as it heats.
  2. Pour water over the contact area as I drill.
  3. Notice my progress.
  4. If progress is rapid, consider moving to a larger bit.
  5. If progress is extremely slow, consider moving to a smaller bit and use more cooling water.
  6. If progress is slow and steady, continue drilling, using the same amount of cooling water.

I have also found that using cooling water that is too cold can cause shattering of either the bit or the object being drilled into.

Always wear protective eyewear, and gloves if they won't get caught.

This technique has worked well for me.

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