Re: [CAD_CAM_EDM_DRO] Dumb question on the drilling of holes

Jon,
Thanks for your input. My spindle is tight, so are the bearings, and
the 1/4" end mill is held in a pretty new collet. When I tried plunging the
end mill through an 1/8" wall aluminum extrusion, I could feel resistance on
the quill. Then I realized that, as the cut started, the chips built up
between the end flutes, and caused some galling and hole distortion, since
the chips, unlike a fluted drill which gets rid of it's own chips, had no
place to go. I'll try to do some testing, and document my findings, to
arrive at the best solution.

Marv Frankel
Los Angeles

----- Original Message -----
From: "Jon Elson" <elson@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, October 22, 2002 10:25 PM
Subject: Re: [CAD_CAM_EDM_DRO] Dumb question on the drilling of holes


>
>
> Marv Frankel wrote:
>
> >Tim,
> > I'm pretty familiar with reaming holes for proper fit, but the
holes
> >I'm talking about, are sometimes so misshapen, they almost look
triangular.
> >They're 1/4" holes, and I've even tried cutting them through with an end
> >mill, and that wasn't great either.
> >
> >
> A properly sharpened drill bit will not do this except on very thin
> sheet. A dull drill bit can
> sure do things like this. End mills generally make VERY round and
> smooth holes, even when
> plunged. If you are trying to plunge an HSS end mill into tool steel,
> however, that could cause
> deflection. Are you sure your spindle is solid? A bad spindle bearing
> or loose quill could
> do this. I hope you aren't holding a 1/4" end mill in a Jacob's chuck.
> That really won't work,
> and isn't safe, either!
>
> Jon
>
>
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