Hah! Yes, that sounds familiar. The rattling and whipping around were the biggest surprises to me when I first saw gundrilling operations. Here was a high-precision machining operation and it sounded like a cross between a popcorn popper and a Caribbean steel band.
Well, I've spent some time with the Guehring people and I have the highest respect for their tools. I'm sure your experience with those setups can teach us a few things.
Hey Karl,
No expert here, but gun-drills and gundrilling require the high pressure "oil" . It is not there so much as a lubricant, but to remove the swarf as it is generated. If the swarf is not removed, it won't drill, or at least not straight. Just "lubricating" or coolant won't cut it !!
Assuming that you can get high-pressure through the drill, CNC should work fine, although if it is a long bore you will need some sort of shank support.
All the accuracy in a gun-drill is in the form of the tip. Look very closely at how it works.
Take care. Good luck.
Brian Lawson, Bothwell, Ontario.
Karl,
We gun drill in our CNC lathe some. We end up hooking up a pressure washer to the coolant lines and use that as a high pressure pump. It works pretty good. Also we gun drill on our horizontal mills, it goes a bit slower, but works for what we need.
Also, we normally either have a bushing help to start the hole, or we bore and/or ream a pilot hole. Once we have a straight hole to start the gun drill, it goes nice and straight.
Thanks, good to know this has been done. Just what i'm going to try. Could you give me some speeds and feeds for the size drills you've run?
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