Marking antenna booms for drilling

[Loren Moline WA7SKT]

Hello all,

When Jim K7ND refered to the article in August QST about building UHF yagis
it brought something to mind I learned about making a straight line
lengthwise on a round pipe.

If you have a piece of angle iron or aluminum like 1/8 by 3/4 or so you can
lay the pipe in the angle and secure it from turning and 1 edge of the angle
will provide an edge to draw a straight line. Then its just a matter of
rotating the pipe 180 deg, securing it and drawing the other line. This
should provide straight elements providing you have a good way to drill
accurately on the lines.

Loren

If I do not dream then it can't come true!
Loren Moline WA7SKT CN86cx
Member: ARRL, Pacific Northwest VHF Society #151

[Loren Moline WA7SKT]

Also when marking the element spacing..use a stainless hose clamp slid on
the pipe just loose enough to slide to make sure the holes on both sides of
the pipe are lined up. This will give you a marking edge.

Loren

[Loren Moline WA7SKT]

Further research shows that in the August QST article by W6PQL he used 1/2
inch aluminum tubing for the boom...In that case 1/8 X 1/2 inch angle would
be in order for the smaller tubing.

Loren

>From: "Loren Moline WA7SKT" <lmo...@hotmail.com>
>Reply-To: lmo...@hotmail.com
>To: pnw...@googlegroups.com
>Subject: [PNWVHFS] Marking antenna booms for drilling
>Date: Fri, 06 Oct 2006 20:54:28 -0700
>
>

[Paul Kiesel]

At first, I tried drawing lines on the tubing, but I
found that doing that really didn't help me; I couln't
get the holes drilled right, anyway. So, what I do is
drill holes for the first element and mount that
element. Now all I do is mount a guide in the proper
position on the drill press table and slide the boom
along the guide. When I come to an element position, I
make sure the mounted element is vertical and then I
will know that the holes I drill will be in their
proper positions.

Paul, K7CW

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[cn85be]

Simply lay a second piece of tubing together with it and run your pen down
them to draw your ultimate straightline. On this line mark your distances.
Drill your holes and bend your elements perpendicular to the boom again if
they are cocked. So simple.

Jeremy

[Eric Smith]

If a long enough flat surface can be prepared next to your
drill press table, one can hose clamp a stick of good ol'
unistrut to the boom. Mark and centerpunch on one side,
and as long as your boom diameters don't change over the
length of the antenna too radically, a stop can be clamped
to the drill press table to run the boom stock along to aid
in aligning the drill bit with the centerpunched hole.
Then you can pretty much drill the whole thing in one
sitting and the elements will be perpendicular to the boom,
and in the same plane. Just slide the unistrutted end away
from the drill press table on your long flat surface. If
the boom is too long for your flat surface, clamp the
'strut to the center of the boom and work out from the
middle, flip, step and repeat. At least that's how I have
built over a half dozen yagis...
Eric
KB7DQH

[Kevin Imel]

If you don't have a drill press, many of the wood working supply houses (Rockler, etc) sell a wonderful plastic jig with steel drill guides that are made just for drilling on non-flat objects.  Reallll handy when drilling booms, round balls, etc.  I think I paid $10 for mine several years ago and it has paid for itself many times over.

 

Of course with the very inexpensive drill presses that are available your excuses for not having a drill press are becoming rather more limited.  ;-)

 

[Cedar Ridge]

This is my preferred method also....and to line up the top and bottom holes
if you are just using a hand drill: Take a piece of masking tape, rap it a
full turn 'plus' around the boom, cut the tape going perpendicularly across
the two overlapped ends, now take the tape off and fold it in half and
crease it, now unfold the tape lay it on a flat surface sticky side down and
draw a straight line across its' length with a ruler. Put the tape on at the
desired element spot and with the pencil line pointing at your punch mark.
If you do it right when the tape is fully rapped around the boom the two
lines on the tape ends will come together at the punch mark and the crease
line and the pencil line will give the the cross hairs on the spot 180 deg
around the boom. Now drill both spots ...... and remember; 'the JA's will
never know if its' not perfectly straight' ;-)))

Hope that helps,

Jason
ve7ag, cn89

----- Original Message -----
From: "Paul Kiesel" <k7...@yahoo.com>
To: <lmo...@hotmail.com>; <pnw...@googlegroups.com>
Sent: Friday, October 06, 2006 9:23 PM
Subject: [PNWVHFS] Re: Marking antenna booms for drilling

>