Originally Posted by air1
The drill bits are numbered drill bit sizes. They come in handy for verifying orifice size and cleaning out orifices. You can get very tiny sizes to clean pilot burner orifices.
Your link did not work, so I have taken the liberty of fixing it.
It is essntially the same as what I said in my post to a simular set of numbered drills , but mine are available in this side of the pond.
Great minds think alike
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