Re: [CAD_CAM_EDM_DRO] more on broken taps

Hi Jon:
Sounds like you are using a very different drill from what I have been
buying.
The ciruit board drills I have bought look like regular right hand spiral
twist drills, but the flutes are cut really deep, so they're skinny and
really brittle.
I get them from KBC.
What is your source, and how are they described in the catalog?
Thanks Jon

Marcus
-----Original Message-----
From: Jon Anderson <janders@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Tuesday, January 16, 2001 11:19 PM
Subject: Re: [CAD_CAM_EDM_DRO] more on broken taps

>Marcus,
>
>Once I broke one when I didn't use the quill feed to control peck depth.
>These really aren't drills, like the half-round drills you see in tool
>catalogs, they look pretty much like a flat bottom single lip cutter
>with a real short flute length.
>
>BTW, once at a previous job in a sheetmetal shop, a custom square die
>for the Amada punch came in without the indexing pin in the side.
>Job needed to be run, no time to return for rework. I was asked to drill
>it, knowing if I messed up we'd have to eat it.
>Hand ground a carbide spade drill, setup the die, and peck drilled
>through the side with about .002 pecks using the CNC. Don't know what
>the rockwell was on those dies, but files would not cut them. Best part
>was when the 3/16 drill left a press-fit hole for a dowel pin.
>Here's a great example of the labor (and arm) saving benefits of CNC!
>
>Jon