I tried to drill a 3/16" cross-hole in a small steel cylinder (0.3125" diameter,
0.400" length). I clamped the cylinder by the ends (faced-off and therefore parallel) in a fairly substantial drill press vise, lined up the center and center-drilled first. Then I tried drilling the hole with a new 135 degree split point drill. The whole assembly started shaking, squealing and in spite of much cutting oil a lot of smoke developed. The drill run at appx. 800 rpm ( a big floor drill).I made it through by gritting my teeth and closing my eyes. Afterward I examined the drill with a magnifying glass and found what I think are small pieces of steel welded on.
An identical drill from the same vendor has no difficulty drilling into steel otherwise.
This is not the first time I have had a problem cross-drilling holes. The clamping arrangements were different but the ensuing effects were pretty much the same.
I cannot understand why this is happening given the solid nature of clamping and all the other factors. I cannot see where flex would occur to produce the extreme form of chatter and subsequent rubbing (which is surely where the smoke and welding effects come from).
It was suggested to me that the part gets distorted as the drilling progresses. It is certainly possible however, the noise etc. starts almost as soon as the drill hits the piece.
I has occured to me that drilling round stock is essentially an interrupted cut until the drill has a chance to sink into the piece fully and engage the flutes 360 degrees. In that case, however, I would have expected the noise etc. to abate which did not happen. Perhaps by that time the drill is too damaged?
What is it about drilling cross holes in small parts that causes these things to happen?
I have tried different clamping arrangements in the past with essentially the same result. I could not really see any other way to clamp this piece differently considering its size and the size of the hole.
To solve this I can only think of drilling with progressively increasing drill sizes (for 3/16" !!!?) or clamping the piece in a 4-jaw chuck and drill it in a lathe.
Any other explanations or suggestions?