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dkaustin
08-15-2007, 01:43 PM
I could use some advice from folks with more experience than I have.

I have sawed off the top of a propane tank (picture a metal cup about a foot in diameter and a foot high), and now I want to clean up the sawed edge.

As you might expect, the rim of this "cup" is pretty limber, even with the base firmly clamped to the table of the milling machine. It tends to shimmy and ring when the cutter bites in (scary AND deafening). Regular side-cutting end mills do NOT seem to be the tool for this job. A slitting saw does somewhat better, but it still doesn't seem to be what the job calls for.

I've tried clamping mass to the rim and cross-bracing the open end of the cup without much noticeable improvement in the situation. I've thought about filling the thing with sand to try and damp out some of the vibration.

Any ideas on how to approach this job? Thanks in advance.

gzig5
08-15-2007, 01:54 PM
Angle grinder/sander and a sharp file....

lynnl
08-15-2007, 02:16 PM
I'd opt for the file. Quieter and more peaceful, and therapeutic to boot.

gld
08-15-2007, 03:19 PM
How about sawing a hole in some plywood slightly smaller than the tank. Sand the hole until you can force it on tank. This should make the wall of tank rigid enough to use a hand grinder.

Alistair Hosie
08-15-2007, 05:03 PM
I had a friend do exactly this with angle grinder with grinding disc then angle grinder fitted with flap discs.Alistair

JCD
08-15-2007, 06:23 PM
Don't know what your tolerance or final application is, but the angle grinder will work with a sanding disk, or if you need greater accuracy the sand will work.

aboard_epsilon
08-15-2007, 06:38 PM
fill the thing full of wet sand

all the best..mark

dkaustin
08-17-2007, 07:16 PM
For the benefit of anyone else who tackles this same problem, packing the thing with sand really did the trick! The job ran so smoothly and quietly that you would have thought I knew what I was doing :-)

Thanks to all who replied. I'm sure the grinder would have worked too if I were less retentive (my problem, not yours).

Thanks again.

Dawai
08-17-2007, 08:51 PM
Aboard said the same thing I was going to say.. Dampen it with sand mass.