there are different angles of flat head screws - I know this from painful
experience on aircraft - and if you get them mixed up you will see exactly
what you are seeing - I don't remember the angles anymore - it could be 82
and 90 degrees, or it could be some other number - if you use one that is
too acute, it sits above the sheet metal, if you use one too obtuse it
doesn't have enough strength, and it's nearly impossible to tell them apart.


"Ned Simmons" wrote in message
...
In article 95M2c.215$yt3.104@newsfep3-
gui.server.ntli.net, says...
"Robin S." wrote in message
...

"Jim" wrote in message
...
For a #6 countersunk machine screw could some one please tell me, or
point
me somewhere I could find out:
a) The diameter of the screw-head
b) The angle of the countersink


Imperial countersunk screws (socket head) have an 82º head. A #6
should
has
a .307Ø theoretical sharp head. If you were to measure one, it could
be as
small as about .263 but your c-sink has to be .307Ø or the top of the
screw
will lie above the top of the work surface.

Regards,

Robin


Thank you Robin, and Errol, for taking the time to find the info and
reply.

I am still slightly confused (I might not have asked the right
questions).
My situation is that I'm using a Hammond aluminum enclosure - dimensions
shown he
http://www.hammondmfg.com/pdf/1455L1601.pdf (150KB)
The #6 machine screws supplied (Phillips) to attach the 1.5mm thick face
panels actually sit proud of the panel.

I'm having some custom panels made up and wanted to get the screws to
sit
flush with the panel. I've had a test panel made with 82deg countersink
angle (sorry, I found that I already had that info) and a maximum
diameter
of 0.240". Now I have the panel back, the maximum diameter seems too big
with the screws in place - there is an easily gap around the edge of the
screwhead. I must have given you the wrong information, as the 0.307Ø is
more than the 0.240Ø that I've tried.


As Robin said, .307 is the max head diameter for a #6 flat
head hex socket screw. For a standard #6 flat head Phillips
or slotted machine screw the max head dia is .279 . If the
head height is greater than the thickness of the panel
you'll have to either put a small contersink in the
threaded hole, or get hold of the flat head screws often
seen on electronic equipment panels where the head is
truncated at the intersection of the head and body. Clear
as mud?

Normal flat head:
________
\ /
\ __ /
| |
| |

Truncated flat head:
________
\______/
| |
| |

Does anyone one know what this head style is called?

Ned Simmons