Nice job on the MQL mister, much less mess than flood coolant.
Couple thoughts on this. As you're finding out, carbide drills don't like opening up existing holes, they much prefer drilling from solid. All carbide drills are not created equal and there are tools designed for high hardness steels. OSG Tap & Die has tools that will drill into the 60's HRC, and I've seen demos of their tools drilling and tapping files. Many other companies have similar tools, but I'm not familiar with distribution in Australia. Word of warning, as the technology increases, so does the price.
Maybe consider trying carbide reamers. They are designed to open existing holes and can take fairly large depth of cuts. Might take a couple of different diameters to arrive at your final dimension. Or, if your finished dimension matches that of an end mill, feeding a four flute end mill with a large corner radius would cut that pin all day.
Not trying to complicate your life here, just throwing out some ideas that might work. Good luck!
Thanks for that, they are great suggestions,
I have adjustable reamers but they would crap out with hardened steel, and I use them to only bore out the stock carbs to 14.6mm than reseat the slide base
Your spot on, they don’t like opening up holes, no drill bits do really
I will look into your suggestion though
First drill bit was $168 and got 7 holes
2nd two $68 and got 3 holes each, but that makes the pins rediculous price I feel
What we suspect is already mentioned and that’s that they loose there coating and just don’t perform and especially that I’m boring out holes
I’m not giving in easy, I will go speak to an experienced machinist and see if I can pinch some of his expert knowledge
How ever I manage to do it must be feasible to do for a reasonable price.