Drilling a flat bottom hole

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PT Doc

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Dec 24, 2011
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Seem like many folks are regularly drilling holes so this might be a useful video. I had inquired about creating a flat bottom hole for a socket head screw and was going to get and end mill to do this. I was going to plunge cut the taper out of a counterbore that I was going to drill with another appropriate sized drill. I do not have a mill and was going to use the drill press. I would ONLY be plunge cutting since we all know that most drill presses cannot take lateral loads well. Seems like many folks did not like this idea and recommended the technique shown in the video labeled How to grind and use a flat bottom drill.

http://m.youtube.com/watch?v=qwuSBJFa5uM

Pretty cool and quick.

Thanks Tom for making the video for me.
 
I'm no machinist but that makes sense to me. Thank you! Here's the embedded video.

[video=youtube;qwuSBJFa5uM]http://www.youtube.com/watch?v=qwuSBJFa5uM&nomobile=1[/video]

I'm going to add this to the Youtube/Video Sticky Thread :thumbup:
 
For use in a drill press (which generally has some spindle slop) this is a better approach than a end mill because the sides of a drill are not grabby, so it won't tend to howl and wobble out your hole. Also, an endmill is not square, it leaves a shallow cone standing out of the bottom of the hole.
 
Very cool, I like the "make your own tools" threads! I've got an old gunsmithing book written during the great depression. It's just chock full of "make it yourself" techniques! Love it!!
 
To make a rough counterbore for , say ,handle materials is not that hard to do .Start with "drill rod " of the outer diameter and turn down the pilot diameter about 1/4" at the end .Then , using your dremel tool or whatever ,cut slots lengtwise in the drill rod and relieve the cutting surfaces a little bit , harden , temper and ...know what I mean?
 
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