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

Hi Marvin:
Aluminum extrusion is gummy, shitty material to try to cut.
You need excellent chip evacuation and flood cooling to have success.
Try a smaller drill to clear the center and then plunge with a boring tool.
Unless you have a pretty rigid mill, I wouldn't try plunging with an
endmill.
Cheers

Marcus

----- Original Message -----
From: "Marv Frankel" <dcdziner@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, October 22, 2002 11:15 PM
Subject: 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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> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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