[time-nuts] Machining some aluminum help!

Joseph Gwinn joegwinn at comcast.net
Sat Jul 29 18:41:08 EDT 2017

On Sat, 29 Jul 2017 12:00:02 -0400, time-nuts-request at febo.com wrote:
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> Date: Fri, 28 Jul 2017 14:11:09 -0700
> From: "Gary E. Miller" <gem at rellim.com>
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Subject: Re: [time-nuts] Machining some aluminum help!
> Message-ID: <20170728141109.71aad750 at spidey.rellim.com>
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> Yo cdelect at juno.com!
> On Fri, 28 Jul 2017 12:46:30 -0700
> <cdelect at juno.com> wrote:
>> After mounting the tap in the drill
>> press and putting a dab of Crisco on the tap I was able to tap each
>> hole to a depth of 7/16" as fast as I could turn the handwheel!
> Cool!
> I suggest you get some real cutting fluid.  The threads will be smoother.

I second that.  What I use is a lubricant wax made by Lenox, the saw 
maker.  It's intended for metal-cutting band saws, but works just 
splendid for form taps.  There are many equivalents.

By the way, when drilling aluminum, use denatured alcohol as the 
cutting fluid.  This will prevent aluminum gumming up the cutting edge 
of the drill.

And, as others have mentioned, one does not use the same size drill for 
forming taps as for cutting taps.  The diameter accuracy required can 
only be achieved by using the correct number (versus fractional) drill 
bit size.  Do not use Chinese drill bits - steel not good enough.  US, 
Japan, Germany et al are OK.

Joe Gwinn

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