The Murphy Builders Site

Late last night as I smoothed all the edges of all flanges and lightening
holes of all the ribs and parts and pieces of my left wing readying them
for chromate I began to wonder just how much is enough and when does it
become too much?

I've been using a commercial triangular carbide deburring tool and a three
side machinists scraper for cleaning the edges of the stamped parts, on the
long heavy gauge parts I us a fine file for the edges, on the parts I
fabricate I polish the edges on 6" scotchbrite wheels as I finish shaping
them. Is polishing better or is simply removing the burr enough? There is
a significant difference in the end result of the varied techniques.

John...


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"Sometimes I wonder whether the world is being run by smart people who
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High John

If it has no burr that will catch your fingernail or skin then I think
it if fine. I think an ever so slightly rounded edge is better but I'm
fairly fussy. I'm talking a radius of one or three thou here such as you
get by wiping the edge with scotchbrite or a light touch of a powered
scotchbrite wheel.

If you have actually thinned the metal near the edge it is too much so
try a lighter touch in future. Thinning the metal near the edge would
make it a bit easier for a crack to start. I have no experience with a
triangular edge deburring tool.

Polishing is probably overkill in that you then have to roughen it again
if you want primer to stick
Of course even untouched sheet should probably be roughened a bit by
hand with scotchbrite before priming.

Ken

John Kramer wrote:

Late last night as I smoothed all the edges of all flanges and lightening
holes of all the ribs and parts and pieces of my left wing readying them
for chromate I began to wonder just how much is enough and when does it
become too much?

I've been using a commercial triangular carbide deburring tool and a three
side machinists scraper for cleaning the edges of the stamped parts, on the
long heavy gauge parts I us a fine file for the edges, on the parts I
fabricate I polish the edges on 6" scotchbrite wheels as I finish shaping
them. Is polishing better or is simply removing the burr enough? There is
a significant difference in the end result of the varied techniques.

John...

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