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Re: [TowerTalk] Drill bits

To: "Tower and HF antenna construction topics." <>
Subject: Re: [TowerTalk] Drill bits
From: "Roger (K8RI)" <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Thu, 25 Mar 2010 23:26:08 -0400
List-post: <">>

N2TK, Tony wrote:
> Many, many years ago when I needed to tap hundreds of holes at a time and do
> it manually. So I took a block of aluminum - 2" X 1.5" X 1"H. I drilled
> clearance holes for #2, 4, 6, 8, 10, 12 and 1/4". This way it is much easier
> to keep the tap at right angles to the hole being tapped. With Tapfree and
> this block I do not break taps.

There is a relatively inexpensive tool that consists of a flared base 
and a tap holder that fits into the machined base. Guarantees a 
straight/90 degree angle. There is also one with a notch that will 
straddle pipe, rod, or tube.


Roger (K8RI)
> 73,
> N2TK, Tony 
> -----Original Message-----
> From:
> [] On Behalf Of Charlie Gallo
> Sent: Thursday, March 25, 2010 1:46 PM
> To: Tower and HF antenna construction topics.
> Subject: Re: [TowerTalk] Drill bits
> On 3/25/2010 wrote:
>> After breaking too many 6-32 and 8-32 taps in vhf/uhf cavity amplifier
>> aluminum parts, I discovered a product named "Tap Magic for Aluminum".
> Tap Magic for Aluminum is excellent - it's my choice #2 after Alumtap
> original.  BTW Tap Magic (without the 'for aluminum') is my choice for most
> other metals
> A trivia for you - 6-32 taps are actually one of the easier taps to break.
> The issue is that of the standard thread series (UNC/UNF) they have the
> worst major/minor diameter ratio, which makes them VERY easy to break.  It's
> actually harder to break a 4-40 tap

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