On Sat, 12 Nov 2016 13:23:22 -0800 (PST), robobass
wrote:

On Thursday, October 13, 2016 at 1:59:47 AM UTC+2, wrote:
On Wed, 12 Oct 2016 12:34:02 -0700 (PDT), SteamboatEd Haas
wrote:

Hey gang I'm making some parts out of delrin; they've got fins on 'em and when they're cut to length the fuzz is everywhere! I'm thinking of using my brass tumbler with walnut shells unless someone's got a better idea. Here's a link to the problem: https://www.flickr.com/photos/steamb...7673545442262/
Walnut shells might work. If they don't then tumbling with abrasive
media and water will. I have deburred acetal plastics, both Delrin and
Acetron, in one of my vibratory tumblers. I used trianglar and
cylindrical abrasive shapes. The only problem is that the plastic will
get a matt finish. For your eventual use I don't think that will
really be a problem. Even walnut shells, if they can remove the burrs,
will give you a matt finish. You can tumble the parts after deburring
with polish but it takes a very long time, in my experience, to polish
acetal plastics in a vibratory tumbler. You might want to try an
abrasive filled nylon brush first to remove the majority of the burrs
first. I have had good luck doing this. It is easy to melt the plastic
if a light touch isn't used though. Even brass wire brushes tend to be
too aggressive.
Eric

Eric, can you point me to a source for fine abrasive filled nylon brushes? I spend a lot of time cleaning 5/16-24 brass threads. I use .2mm bristle brass brush wheels and tripoli. It works, but I'm on the lookout for something better.
Does MSC sell to your part of the world? They sell Weiler brand nylon
wheel brushes that have a filament diameter that is nominally .018 but
can be as small as .010. I have used these brushes and the ends can
wear to a point which is what you need to get into the root of a 24
TPI thread. Weiler does make good brushes and with that name may be
made much closer to you than me here north of Seattle. Have you
considered fine steel brushes? They cut fast and can be too aggressive
on soft metals like annealed brass. But a light and quick touch could
result in a roughing op. that leaves the surface perfect for a fast
tripoli treatment. You could try a jewellry supply company for the
brush but they tend to carry ones that are too small. I have had the
occasion more than once to polish small brass threaded parts and found
that E5 emery on the right buff will cut fast, get to the root of the
thread, and leave a finish that is usually already good enough and if
not then either tripoli are rouge can be used. For REALLY nice color
on brass I like Fabuluster. But that's probably more work than you
need to do if you are stopping at the Tripoli stage. BTW, did any of
the sprayer suggestions here pan out?
Eric