[NCARC] Grumble, Grumble

[Steve Henry]

Hi Kerry-

Hope you're doing well-- long time no chat!  Could indeed be an inexpensive
tool as Willis points out.   The other thing that can happen is that
aluminum can melt when being cut/machined.  Typically the fiber disks have a
grit mixed in with them and ones that do well at cutting aluminum are
designed to poke through the melted aluminum and continue to have a sharp
cutting surface.  Otherwise it's easy to press harder and harder on the
wheel to try and cut which only increases the melting and destroys the
grinding wheel (and your patience!).   Good article here that might help on
the technique side if the fiber disks you have are designed to cut aluminum:

http://www.thefabricator.com/article/finishing/gearing-up-to-grind-aluminum

I'm in the second semester of the precision machining credential program at
front range (quite an education!).  The first thing they teach us is to
never use the grinding machines to cut aluminum because it's so soft it
plugs up the wheels.  Someone invariably forgets (I almost did) and it
destroys wheels that otherwise normally do a very nice job grinding steel.

'73

Steve Henry, N7GN





-----Original Message-----
From: NCARC [mailto:ncarc-bounces at mailman.qth.net] On Behalf Of Willis
Whatley
Sent: Sunday, August 28, 2016 4:26 AM
To: 'Kerry Miller'; 'NCARC'
Subject: Re: [NCARC] Grumble, Grumble

Pure aluminum is significantly soft.  That is why it is almost always
alloyed with other materials to bring the hardness up to an acceptable level
on the Brinell, Vickers or Rockwell scales based on what it will be used
for.

The other problem may be that the tool you were using was obtained from
Harbor Freight...  Hi, Hi.


73,

WA5VRL
Willis


-----Original Message-----
From: NCARC [mailto:ncarc-bounces at mailman.qth.net] On Behalf Of Kerry Miller
Sent: Saturday, August 27, 2016 12:49 PM
To: NCARC
Subject: [NCARC] Grumble, Grumble

Hi People,

I was doing fine cutting the slits in an aluminum tub until the fiber blade
made for cutting metal wore down to small to continue.  This was a blade
that came with my RotoZip tool.  I thought Aluminum was supposed to be soft.
I had four of these slots to cut and I got maybe  1 and 1/3 slots cut.

-- 

Kerry N0WIQ

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