Drilling Cross Holes

[kingmt01]

one thing to do when drilling a round surface in the mill is to hit it with a flat mill bit to give yourself a flat surface to drill so the bit won't wander...doesn't need to be a deep or wide cut just enough to give you a starting point for the drill tip

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Gives you a nice reference to help you feel better you are on center also. If I just need a hole & it doesn't have to be held to a really tight tolerance then I'll just spot the top to find center. You can get very close this way.

 

[RandyM]

one thing to do when drilling a round surface in the mill is to hit it with a flat mill bit to give yourself a flat surface to drill so the bit won't wander...doesn't need to be a deep or wide cut just enough to give you a starting point for the drill tip

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Yup, or you can use a center drill first. I center drill everything.

 

[Wreck™Wreck]

Yup, or you can use a center drill first. I center drill everything.

Try a spotting drill instead and you will prefer it to a center drill. Center drills are for producing centers for work holding purposes.

 

[EmilioG]

I'm making some steel cutter blocks from square and hex 1018 just for this type of work.
You can turn the part on the flats. Lautards BSR #1 shows this. A set screw holds the work and you can
make collets or ream diameters to suit.

 

[jamby]

I have aligned 90 deg holes by putting the part in a V-block and scribing a center line from 90 deg and 0 deg then eye ball the lines with a square when set up to drill.

Jim