[TowerTalk] Drilling Chrome-Moly Steel

[Mike]

About a year ago, I drilled and pinned a 2" chrome moly mast on the
tower (70') for the local club station. We used a Makita cordless 
drill and some brand new HSS bits. I was pleasantly surprised at 
how quickly we were able to penetrate the moly tubing (5 to 10 
minutes).If you use a cordless drill make sure you battery is fully
charged, or that you have a spare battery around. We drilled several
holes and had to change batteries in the middle of the job. 

73 de Mike, W4EF.......................

P.S. Make sure you buy good drill bits from a industrial supply house 
like MSC or McMaster Carr. The cheap import bits you find floating
around the home supply stores probably aren't up to the job. 

----- Original Message ----- 
From: <kk9a@arrl.net>
To: <w0yg@prolynx.com>; <towertalk@contesting.com>
Sent: Monday, June 18, 2001 5:47 PM
Subject: Fw: [TowerTalk] Drilling Chrome-Moly Steel w0yg@prolynx.com


> In a machine shop I used to drill 4140 Chrome-Moly with regular
> High Speed Steel drill bits.  This was in a drill press, I know that it's
> a lot tougher with a hand drill on a tower.  I still think a regular HSS
> drill should work for you.  Be careful not to run it too fast and work
> harden the surface and also use a cutting oil.
> 73,
> John
> 
> -----Original Message-----
> From: Charlie Summers
> To: towertalk@contesting.com
> Sent: 6/18/2001 4:28 PM
> Subject: [TowerTalk] Drilling Chrome-Moly Steel
> 
> Can someone please tell me what type of drill bit I need to drill out a
> 5/16" diameter hole in my existing 2" mast with 3/8" wall.  I want to go
> to
> 5/8 if possible but the mast may just be too hard.
> 
> I would rather stay away from the real expensive, like $150.00, drill
> bits,
> instead preferring to use several say cobalt tipped or titanium tipped
> or
> some kind of hardened steel bit.
> 
> I have looked at McMaster-Carr's catalog and see what they recommend in
> print but was hoping someone would be able to give me guidance based on
> experience.
> 
> The other hooker is I have to drill this on the top of a tower so
> staying
> there for hours will not be pleasant, especially with a heavy half inch
> drill.
> 
> This is a rather personal request on a Tower-Talk related subject so
> personal replies might be in order to:  w0yg@prolynx.com
> 
> Thanks and 73,
> 
> Charlie, W0YG..>>
> 
> 
> 
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> 
> List Sponsor: Are you thinking about installing a tower this summer? Call us
> for information on our fabulous Trylon Titan self-supporting towers - up to
> 96-feet for less than $2000! at 888-833-3104 <A HREF="http://www.ChampionRadio.com">
> www.ChampionRadio.com</A>
> 
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List Sponsor: Are you thinking about installing a tower this summer? Call us
for information on our fabulous Trylon Titan self-supporting towers - up to
96-feet for less than $2000! at 888-833-3104 <A HREF="http://www.ChampionRadio.com">
www.ChampionRadio.com</A>

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