[Amps] Workshop Danger

[Fuqua, Bill L]

   The more common fly cutters, purchased as Sears, Harbor Freight, etc. are not sturdy enough and
flex and chatter during use. They are no problem usually when  making holes in wood. But unless you
have an expensive sturdy fly cutter, and sturdy milling machine or drill press, the cutter will grab  the 
soft 1100 aluminum and then it is a matter of what gives first. It could be the clamps on holding
the aluminum, the belts slip on the drill press or in some cases the fly cutter will end up being
twisted out of shape. The instructions for these common fly cutters suggest that they can be used
in with a handheld drill. 
  I either use, when possible, Whitney Punches (expensive), Greenlee Punches, also expensive, or 
hole saws. And sometimes drilling many holes and file.
73
Bill wa4lav

________________________________________
From: Amps [amps-bounces at contesting.com] on behalf of Jim Thomson [jim.thom at telus.net]
Sent: Friday, September 13, 2013 10:47 AM
To: amps at contesting.com
Subject: [Amps]  Workshop Danger

Date: Fri, 13 Sep 2013 06:24:16 -0600
From: "Jim Garland" <4cx250b at miamioh.edu>
To: <amps at contesting.com>
Subject: [Amps] Workshop Danger

My least favorite part of homebrewing an amplifier is making the meter
cutouts and tube socket holes. Last evening I cut three 2.90 holes for
GU-74Bs and survived the experience. I have a set of hole saws, but not
metric ones for Russian tubes, and therefore had to use a fly-cutter. IMHO,
fly-cutters are the most dangerous tool in a workshop. I hate the things. I
securely clamped the sheet aluminum stockl to the bed of a large
(floor-mounted) drill press, set the drill press on its slowest speed, and
used aluminum cutting fluid. One has to advance the fly-cutter VERY slowly
to prevent the cutting tool from grabbing the aluminum. If that happens, the
sheet aluminum is likely to go flying around in a big circle like a sythe.
The other danger is absent-mindedness, which can lead the drill press
operator to reach in with his fingers to remove a piece of aluminum debris.
Fly-cutters should never be used with a hand drill, as I stupidly tried once
as a teen-ager. They absolutely require a large floor-mounted drill press
with a sizeable bed.

73,Jim Garland W8ZR

##  A W6 sent me a fly cutter so I could cut holes for my 2 x 4-1000 amp.   I used
a hand drill, since the huge STEEL chassis  would not fit into my drill press !
Also had to use it to cut  5 x meter holes..also in a  STEEL front panel.

##  after just about  killing my new wife and myself at the time... this was on the kicthen
floor too,   I took the entire mess to work, and borrowed the electricians  hydraulic
green lee punchs..wham bam..done.    Don’t EVER  use steel  for either a chassis or a front panel.

##  I have a huge set of green lee punchs..that do meter holes, socket holes etc...that came with the
big greenlee wrench.   Then bought a  similar set from harbor freight, which also include the 11 ton hydraulic
hand pump.  The chinese knock off was $99.00   The identical hydraulic punch and 7 x greenlee punchs is $1300.00  !!

##  The chinese knock off has not let me down yet....and the hydraulic punch also works  with my green lee punchs !
##  I now have a modified drill press that will handle huge sheets  of AL.   Also have the bench mount roper whitney 5 ton
punch with the 30 inch arm.   Why drill  hundreds of .187 holes..when you can punch em  20 times faster than
any drill press.   These new greenlee /chinese punchs are slick, they also split the slug clean in half too. making
its removal easier.

## dunno what happened to the fly cutter.  I did cringe one day though... I saw an even bigger version of the same fly cutter,
huge thing, that would cut a 16 inch  hole.   greenlee also now makes  hole saws that will cut clean holes in al plate.
Electricians at most places will use em.   My buddies at work had greenlee punchs  up to over 6 inchs !    Now those
are great things when doing  100 cfm fans that need a 4 inch hole etc.

##  My bosch jig saw looks like a sausage....and with the thin blades, will easily cut a 3 inch perfect hole, freehand,
into  .375 inch thick  AL plate.   those blades are good up to .75 inch thick AL plate.

##  fly cutters... forget it, toss em.   They really should be banned.

Jim  VE7RF


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